Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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Article

11 pages, 1708 KiB  
Article
Ovicidal and Physiological Effects of Essential Oils Extracted from Six Medicinal Plants on the Elm Leaf Beetle, Xanthogaleruca luteola (Mull.)
by Bita Valizadeh, Jalal Jalali Sendi, Marziyeh Oftadeh, Asgar Ebadollahi and Patcharin Krutmuang
Agronomy 2021, 11(10), 2015; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102015 - 7 Oct 2021
Cited by 7 | Viewed by 2300
Abstract
Plant essential oils may serve as safe alternatives to detrimental synthetic pesticides due to relatively lower side effects on the environment and non-targeted organisms. The current study was conducted to investigate the ovicidal toxicity and physiological disruptions of six medicinal plant essential oils, [...] Read more.
Plant essential oils may serve as safe alternatives to detrimental synthetic pesticides due to relatively lower side effects on the environment and non-targeted organisms. The current study was conducted to investigate the ovicidal toxicity and physiological disruptions of six medicinal plant essential oils, including Artemisia annua L., Lavandula angustifolia Mill., Origanum vulgare L., Rosmarinus officinalis Spenn., Satureja hortensis L., and Thymus vulgaris L., on elm leaf beetle Xanthogaleruca luteola (Mull.). The LC50 (Lethal Concentration to kill 50% of tested insects) values of 122.8, 287.5, 152.8, 180.6, 315.9, and 1366.2 ppm were recorded for T. vulgaris, L. angustifolia, A. annua, S. hortensis, R. officinalis, and O. vulgare, respectively, 72 h after treatment of 3-day-old eggs of the pest. Significant decreases in the amounts of glucose, protein, and triglyceride macromolecules were also observed after treatment. The application of essential oils derived from T. vulgaris, A. annua, and S. hortensis at 400 ppm revealed 100% ovicidal activity. Accordingly, tested essential oils, particularly the essential oil of T. vulgaris, have been promising potential as biorational insecticides in the management of X. luteola. Full article
(This article belongs to the Special Issue Advances in Pesticide Discovery and Application)
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22 pages, 1493 KiB  
Article
Multi-Environment Yield Components in Advanced Common Bean (Phaseolus vulgaris L.) × Tepary Bean (P. acutifolius A. Gray) Interspecific Lines for Heat and Drought Tolerance
by Esteban Burbano-Erazo, Rommel Igor León-Pacheco, Carina Cecilia Cordero-Cordero, Felipe López-Hernández, Andrés J. Cortés and Adriana Patricia Tofiño-Rivera
Agronomy 2021, 11(10), 1978; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11101978 - 30 Sep 2021
Cited by 33 | Viewed by 3357
Abstract
Heat and drought are major stresses that significantly reduce seed yield of the common bean (Phaseolus vulgaris L.). In turn, this affects the profitability of the crop in climatic-vulnerable tropical arid regions, which happen to be the poorest and in most need [...] Read more.
Heat and drought are major stresses that significantly reduce seed yield of the common bean (Phaseolus vulgaris L.). In turn, this affects the profitability of the crop in climatic-vulnerable tropical arid regions, which happen to be the poorest and in most need of legume proteins. Therefore, it is imperative to broaden the sources of heat and drought resistance in the common bean by examining closely related species from warmer and drier environments (i.e., Tepary bean, P. acutifolius A. Gray), while harnessing such variation, typically polygenic, throughout advanced interspecific crossing schemes. As part of this study, interspecific congruity backcrosses for high temperature and drought tolerance conditions were characterized across four localities in coastal Colombia. Genotypes with high values of CO2 assimilation (>24 µmol CO2 m−2 s−1), promising yield scores (>19 g/plant), and high seed mineral content (Fe > 100 mg/kg) were identified at the warmest locality, Motilonia. At the driest locality, Caribia, one intercrossed genotype (i.e., 85) and the P. acutifolius G40001 control exhibited sufficient yield for commercial production (17.76 g/plant and 12.76 g/plant, respectively). Meanwhile, at southernmost Turipaná and Carmen de Bolívar localities, two clusters of genotypes exhibited high mean yield scores with 33.31 g/plant and 17.89 g/plant, respectively, and one genotype had an increased Fe content (109.7 mg/kg). Overall, a multi-environment AMMI analysis revealed that genotypes 13, 27, 82, and 84 were environmentally stable with higher yield scores compared to the Tepary control G40001. Ultimately, this study allows us to conclude that advanced common bean × Tepary bean interspecific congruity backcrosses are capable of pyramiding sufficient polygenic tolerance responses for the extreme weather conditions of coastal Colombia, which are likely to worsen due to climate change. Furthermore, some particular recombination events (i.e., genotype 68) show that there may be potential to couple breeding for heat and drought tolerance with Fe mineral biofortification, despite a prevalent trade-off, as a way to fight malnutrition of marginalized communities in tropical regions. Full article
(This article belongs to the Special Issue Omics Approaches for Crop Improvement)
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19 pages, 534 KiB  
Article
Does Digital Financial Inclusion Affect Agricultural Eco-Efficiency? A Case Study on China
by Jiehua Ma and Zhenghui Li
Agronomy 2021, 11(10), 1949; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11101949 - 28 Sep 2021
Cited by 23 | Viewed by 2816
Abstract
Agricultural eco-efficiency can effectively reflect the coordinated green and balanced development of rural resources, and digital financial inclusion provides a strong financial power in the process of long-term balanced development of rural areas. There may be a complex relationship between the two. Therefore, [...] Read more.
Agricultural eco-efficiency can effectively reflect the coordinated green and balanced development of rural resources, and digital financial inclusion provides a strong financial power in the process of long-term balanced development of rural areas. There may be a complex relationship between the two. Therefore, based on the panel data of 30 provinces, autonomous regions, and municipalities in mainland China from 2011 to 2018, this paper explores the impact of digital financial inclusion on agricultural eco-efficiency through the differential GMM method. Further, the paper analyzes how digital financial inclusion influences agricultural eco-efficiency by influencing the agricultural scientific and technological investment. The following conclusions are drawn. First, there is a positive U-shaped nonlinear relationship between digital financial inclusion and agricultural eco-efficiency. Second, the impact of digital financial inclusion on agricultural eco-efficiency is of regional heterogeneity. Digital financial inclusion has a significant positive U-shaped impact on agricultural eco-efficiency in central China but has no significant impact on Eastern and Western China. Third, agricultural R&D investment will intensify the promotion effect of digital financial inclusion on agricultural eco-efficiency. Full article
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20 pages, 3790 KiB  
Article
Evaluating the Spectral and Physiological Responses of Grapevines (Vitis vinifera L.) to Heat and Water Stresses under Different Vineyard Cooling and Irrigation Strategies
by Alessia Cogato, Lihua Wu, Shaikh Yassir Yousouf Jewan, Franco Meggio, Francesco Marinello, Marco Sozzi and Vinay Pagay
Agronomy 2021, 11(10), 1940; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11101940 - 27 Sep 2021
Cited by 19 | Viewed by 3248
Abstract
Heat stress (HS) and water stress (WS) pose severe threats to viticulture, and effective management solutions to counter their effects on grapevine performance must be examined. In this study, we evaluated the physiological and spectral responses of Vitis vinifera L. cv. Sauvignon blanc [...] Read more.
Heat stress (HS) and water stress (WS) pose severe threats to viticulture, and effective management solutions to counter their effects on grapevine performance must be examined. In this study, we evaluated the physiological and spectral responses of Vitis vinifera L. cv. Sauvignon blanc to individual (HS) and combined (HS + WS) stress under four different cooling and irrigation strategies. The treatments were: standard drip irrigation (SI), extra drip irrigation (SI+), extra sprinklers irrigation (SPRI), and sustained deficit irrigation (SDI; 50% of SI). Compared to the other treatments, in the early stages after the occurrence of HS, the vine water status of SPRI and SI+ improved, with high stomatal conductance (gs) (SPRI) and stem water potential (Ψstem; SPRI and SI+). All the physiological indicators measured were significantly lower after the end of HS in the SDI treatment. We also identified the spectral response of grapevine to HS and combined HS and WS (resulting from SDI). Consistent with the physiological analysis, the proximal spectral responses of leaves identified SPRI and SI+ as putative cooling strategies to minimize vine HS. The vines undergoing combined stress (SDI) showed greenness amelioration 10 days after stress, as revealed by the greenness vegetation indices (VIs), i.e., Green Index (GI), Normalized Difference Greenness Vegetation Index (NDGI), and Visible Atmospherically Resistant Index (VARI). However, their physiological recovery was not achieved within this time, as shown by the Simple Ratio Index (SRI), Transformed Chlorophyll Absorption Ratio Index (TCARI), and TCARI/Optimized Soil-Adjusted Vegetation Index (TCARI/OSAVI). A three-step band selection process allowed the identification of the spectral traits’ responsive to HS and combined stress, i.e., 1336–1340 nm, 1967–1971 nm, and 600–604 nm. Full article
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22 pages, 4458 KiB  
Article
Economic Feasibility of Agrivoltaic Systems in Food-Energy Nexus Context: Modelling and a Case Study in Niger
by Srijana Neupane Bhandari, Sabine Schlüter, Wilhelm Kuckshinrichs, Holger Schlör, Rabani Adamou and Ramchandra Bhandari
Agronomy 2021, 11(10), 1906; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11101906 - 23 Sep 2021
Cited by 24 | Viewed by 6036
Abstract
In the literature, many studies outline the advantages of agrivoltaic (APV) systems from different viewpoints: optimized land use, productivity gain in both the energy and water sector, economic benefits, etc. A holistic analysis of an APV system is needed to understand its full [...] Read more.
In the literature, many studies outline the advantages of agrivoltaic (APV) systems from different viewpoints: optimized land use, productivity gain in both the energy and water sector, economic benefits, etc. A holistic analysis of an APV system is needed to understand its full advantages. For this purpose, a case study farm size of 0.15 ha has been chosen as a reference farm at a village in Niger, West Africa. Altogether four farming cases are considered. They are traditional rain-fed, irrigated with diesel-powered pumps, irrigated with solar pumps, and the APV system. The APV system is further analyzed under two scenarios: benefits to investors and combined benefits to investors and farmers. An economic feasibility analysis model is developed. Different economic indicators are used to present the results: gross margin, farm profit, benefit-cost ratio, and net present value (NPV). All the economic indicators obtained for the solar-powered irrigation system were positive, whereas all those for the diesel-powered system were negative. Additionally, the diesel system will emit annually about 4005 kg CO2 to irrigate the chosen reference farm. The land equivalent ratio (LER) was obtained at 1.33 and 1.13 for two cases of shading-induced yield loss excluded and included, respectively. Full article
(This article belongs to the Special Issue Photovoltaics and Electrification in Agriculture)
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17 pages, 2504 KiB  
Article
Halotolerant-Koccuria rhizophila (14asp)-Induced Amendment of Salt Stress in Pea Plants by Limiting Na+ Uptake and Elevating Production of Antioxidants
by Amir Abdullah Khan, Tongtong Wang, Tayyaba Hussain, Amna, Fayaz Ali, Fuchen Shi, Arafat Abdel Hamed Abdel Latef, Omar M. Ali, Kashif Hayat, Shehzad Mehmood, Nida Zainab, Muhammad Atif Muneer, Muhammad Farooq Hussain Munis, Mona H. Soliman and Hassan Javed Chaudhary
Agronomy 2021, 11(10), 1907; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11101907 - 23 Sep 2021
Cited by 15 | Viewed by 2692
Abstract
Endophytic bacteria are useful for their safe services in plant growth improvement and for ameliorating abiotic and biotic stresses. Salt-tolerant plant-growth-promoting Kocuria rhizophila 14asp (accession number KF 875448) was investigated for its role in pea plants under a saline environment. Salt stress (75 [...] Read more.
Endophytic bacteria are useful for their safe services in plant growth improvement and for ameliorating abiotic and biotic stresses. Salt-tolerant plant-growth-promoting Kocuria rhizophila 14asp (accession number KF 875448) was investigated for its role in pea plants under a saline environment. Salt stress (75 mM and 150 mM NaCl) was subjected to two pea varieties, peas2009 and 9800-10, in a greenhouse under a complete randomized design. Different parameters such as plant growth promotion, relative water content, chlorophyll, antioxidants, and mineral contents were analyzed to elucidate the extent of tolerance persuaded by PGPB (plant-growth-promoting bacteria). Exhibition of adverse effects was noticed in uninoculated varieties. However, inoculation of K. rhizophila improved the morphological parameters, antioxidant enzymes, and minimized the uptake of Na+ in plants under various saline regimes. Pea variety 9800-10 exhibited more tolerance than peas2009 in all traits, such as root and shoot length, fresh and dry biomass, chlorophyll contents, and antioxidant enzymes. Our results showed that halotolerant K. rhizophila inoculation plays a vital role in enhancing plant growth by interacting ingeniously with plants through antioxidant systems, enduring saline conditions. Full article
(This article belongs to the Special Issue Crop Physiological Responses to Abiotic Stress Factors)
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23 pages, 16545 KiB  
Article
Grape Bunch Detection at Different Growth Stages Using Deep Learning Quantized Models
by André Silva Aguiar, Sandro Augusto Magalhães, Filipe Neves dos Santos, Luis Castro, Tatiana Pinho, João Valente, Rui Martins and José Boaventura-Cunha
Agronomy 2021, 11(9), 1890; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091890 - 21 Sep 2021
Cited by 38 | Viewed by 4340
Abstract
The agricultural sector plays a fundamental role in our society, where it is increasingly important to automate processes, which can generate beneficial impacts in the productivity and quality of products. Perception and computer vision approaches can be fundamental in the implementation of robotics [...] Read more.
The agricultural sector plays a fundamental role in our society, where it is increasingly important to automate processes, which can generate beneficial impacts in the productivity and quality of products. Perception and computer vision approaches can be fundamental in the implementation of robotics in agriculture. In particular, deep learning can be used for image classification or object detection, endowing machines with the capability to perform operations in the agriculture context. In this work, deep learning was used for the detection of grape bunches in vineyards considering different growth stages: the early stage just after the bloom and the medium stage where the grape bunches present an intermediate development. Two state-of-the-art single-shot multibox models were trained, quantized, and deployed in a low-cost and low-power hardware device, a Tensor Processing Unit. The training input was a novel and publicly available dataset proposed in this work. This dataset contains 1929 images and respective annotations of grape bunches at two different growth stages, captured by different cameras in several illumination conditions. The models were benchmarked and characterized considering the variation of two different parameters: the confidence score and the intersection over union threshold. The results showed that the deployed models could detect grape bunches in images with a medium average precision up to 66.96%. Since this approach uses low resources, a low-cost and low-power hardware device that requires simplified models with 8 bit quantization, the obtained performance was satisfactory. Experiments also demonstrated that the models performed better in identifying grape bunches at the medium growth stage, in comparison with grape bunches present in the vineyard after the bloom, since the second class represents smaller grape bunches, with a color and texture more similar to the surrounding foliage, which complicates their detection. Full article
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30 pages, 3936 KiB  
Article
Organic Matter and Mineral Composition of Silicate Soils: FTIR Comparison Study by Photoacoustic, Diffuse Reflectance, and Attenuated Total Reflection Modalities
by Dmitry S. Volkov, Olga B. Rogova and Mikhail A. Proskurnin
Agronomy 2021, 11(9), 1879; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091879 - 19 Sep 2021
Cited by 44 | Viewed by 5276
Abstract
This study aims to compare photoacoustic (FTIR–PAS), diffuse reflectance (DRIFT), and attenuated total reflection (ATR) FTIR modalities in the wide wavenumber range from NIR (7500 cm−1) to FIR (150 cm−1) for the same silicate soil samples under the same [...] Read more.
This study aims to compare photoacoustic (FTIR–PAS), diffuse reflectance (DRIFT), and attenuated total reflection (ATR) FTIR modalities in the wide wavenumber range from NIR (7500 cm−1) to FIR (150 cm−1) for the same silicate soil samples under the same conditions. The possibilities of non-destructive rapid qualitative analysis of soils by these modalities without comprehensive data treatment were compared. The assignment of more than 100 bands for the chernozem and sod-podzolic as common types of silicate types of soil was made. The following groups of bands of organic matter and inorganic matrix were reliably found in spectra of all or at least two modalities: 3690–3680 cm−1 (hydrogen-bonded SiO–H…H2O stretch, not ATR), 2930–2910 cm−1 and 2860–2850 cm−1 (methylene stretch), 1390–1380 cm−1, (symmetric stretch carboxylate, DRIFT and FTIR–PAS); 2000–1990 cm−1, 1885 cm−1, and 1790–1783 cm−1 (SiO2 overtones, DRIFT and FTIR–PAS), 1163–1153 cm−1, SiO2 lattice (not FTIR–PAS), 1037 cm−1 (Si–O or Al–O stretch), 796 cm−1 (lattice symmetrical Si–O–Si stretch); 697 cm−1, SiO2; and 256 cm−1 (not FTIR–PAS). Amide I, II, and III bands appear in DRIFT and FTIR–PAS spectra while not in ATR. Except for methylene and carboxylate groups, CH vibrations (3100–2900 cm−1) are not seen in ATR. Bands at 1640–1630 cm−1, 1620–1610 cm−1, 1600–1598 cm−1 (primary water bands and probably carboxylate) appear in the spectra of all three modalities but are unresolved and require data treatment. It is preferable to use all three modalities to characterize both soil organic matter and mineral composition. DRIFT provides the maximum number of bands in all three modalities and should be selected as a primary technique in the NIR and 4000–2000 cm−1 regions for hydrogen-bonding bands, CHX groups, and the silicate matrix. ATR–FTIR complements DRIFT and provides a good sensitivity for soil water and the matrix in 2000–400 cm−1. FTIR–PAS in 4000–1500 cm−1 reveals more bands than DRIFT and shows the highest sensitivity for absorption bands that do not appear in DRIFT or ATR-IR spectra. Thus, FTIR–PAS is expedient for supporting either DRIFT or ATR–FTIR. This modality comparison can be a basis for methodological support of IR spectroscopy of soils and similar organomineral complexes. Full article
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14 pages, 649 KiB  
Article
Seed Priming with Sulfhydral Thiourea Enhances the Performance of Camelina sativa L. under Heat Stress Conditions
by Ejaz Ahmad Waraich, Muhammad Ahmad, Walid Soufan, Muhammad Taimoor Manzoor, Zahoor Ahmad, Muhammad Habib-Ur-Rahman and Ayman EL Sabagh
Agronomy 2021, 11(9), 1875; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091875 - 17 Sep 2021
Cited by 12 | Viewed by 2971
Abstract
Temperature is a key factor influencing plant growth and productivity; however, temperature fluctuations can cause detrimental effects on crop growth. This study aimed to assess the effect of seed priming on Camelina sativa L. under heat stress. Experimental treatments were comprised of; seed [...] Read more.
Temperature is a key factor influencing plant growth and productivity; however, temperature fluctuations can cause detrimental effects on crop growth. This study aimed to assess the effect of seed priming on Camelina sativa L. under heat stress. Experimental treatments were comprised of; seed priming including, no-priming, hydropriming (distilled water priming), and osmopriming (thiourea applications at 500 ppm), heat stress (control = 20 °C and heat stress = 32 °C), and camelina varieties (7126 and 8046). Heat stress hammered crop growth as relative water content and photosynthetic rate were reduced by 35.9% and 49.05% in 7126, respectively, and 25.6% and 41.2% in 8046 as compared with control-no thiourea applied. However, osmopriming with thiourea improved the root and shoot length, and biomass production compared to control–no application under heat stress, with more improvement in variety 8046 as compared with 7126. Moreover, the maximum values of gas exchange and water relations were recorded at thiourea priming and no stress as compared with no-priming under heat stress that helped to improve seed yield by 12% in 7126 and 15% in 8046, respectively. Among the varieties, camelina variety 8046 showed better performance than 7126 by producing higher seed yield especially when subjected to thiourea priming. In conclusion, thiourea seed priming helped the plants to mitigate the adverse effects of heat stress by upregulating plant physiological attributes that lead to maintain camelina seed yield. Full article
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14 pages, 2798 KiB  
Article
GGE Biplot Analysis of Genotype × Environment Interaction and Yield Stability in Bambara Groundnut
by Oluwaseyi Samuel Olanrewaju, Olaniyi Oyatomi, Olubukola Oluranti Babalola and Michael Abberton
Agronomy 2021, 11(9), 1839; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091839 - 14 Sep 2021
Cited by 24 | Viewed by 5129
Abstract
In plant breeding and agricultural research, biplot analysis has become an important statistical technique. The goal of this study was to find the winning genotype(s) for the test settings in a part of the Southwest region of Nigeria, as well as to investigate [...] Read more.
In plant breeding and agricultural research, biplot analysis has become an important statistical technique. The goal of this study was to find the winning genotype(s) for the test settings in a part of the Southwest region of Nigeria, as well as to investigate the nature and extent of genotype × environment interaction (GEI) effects on Bambara groundnut (BGN) production. The experiment was carried out in four environments (two separate sites, Ibadan and Ikenne, for two consecutive years, 2018 and 2019) with ninety-five BGN accessions. According to the combined analysis of variance over environments, genotypes and GEI both had a substantial (p < 0.001) impact on BGN yield. The results revealed that BGN accessions performed differently in different test conditions, indicating that the interaction was crossover in nature. The results revealed that BGN accessions performed differently in different test conditions, indicating that the interaction was crossover in nature. To examine and show the pattern of the interaction components, biplots with the genotype main effect and genotype × environment interaction (GEI) were used. The first two PCs explained 80% of the total variation of the GGE model (i.e., G + GE) (PC1 = 48.59%, PC2 = 31.41%). The accessions that performed best in each environment based on the “which-won-where” polygon were TVSu-2031, TVSu-1724, TVSu-1742, TVSu-2022, TVSu-1943, TVSu-1892, TVSu-1557, TVSu-2060, and TVSu-2017. Among these accessions, TVSu-2017, TVSu-1557, TVSu-2060, TVSu-1892, and TVSu-1943 were among the highest-yielding accessions on the field. The adaptable accessions were TVSu-1763, TVSu-1899, TVSu-2019, TVSu-1898, TVSu-1957, TVSu-2021, and TVSu-1850, and the stable accessions were TVSu-1589, TVSu-1905, and TVSu-2048. In terms of discriminating and representativeness for the environments, Ibadan 2019 is deemed to be a superior environment. The selected accessions are recommended as parental lines in breeding programs for grain yield improvement in Ibadan or Ikenne or similar agro-ecological zones. Full article
(This article belongs to the Special Issue Analysis of the Genetic Diversity of Crops and Associated Microbiota)
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22 pages, 1616 KiB  
Article
Determinants and Mechanisms of Digital Financial Inclusion Development: Based on Urban-Rural Differences
by Guang Liu, Yunying Huang and Zhehao Huang
Agronomy 2021, 11(9), 1833; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091833 - 13 Sep 2021
Cited by 30 | Viewed by 4970
Abstract
The combination of digital finance and financial inclusion can better meet the needs of those who have little access to financial services. This paper investigated the differences in the determinants and mechanisms of digital financial inclusion development between urban and rural areas. The [...] Read more.
The combination of digital finance and financial inclusion can better meet the needs of those who have little access to financial services. This paper investigated the differences in the determinants and mechanisms of digital financial inclusion development between urban and rural areas. The sample consists of 1607 counties in China from 2014 to 2019, and uses the fixed-effect model and panel threshold technique. The empirical results indicate that: (1) The industrial economy and governmental intervention are the common determinants of urban and rural digital financial inclusion development, in which the degree is different. At the same time, secondary education is only a determinant in rural areas. (2) Industrial upgrading and indirect finance play a mediating role in the determinants of digital financial inclusion, but indirect finance is only significant for urban areas. (3) There is a threshold effect in the financial development-digital financial inclusion relationship. Under different financial development levels, the determinants of urban and rural digital financial inclusion show the discrepancy. With the development of digital financial inclusion under the trend of promoting innovative digital finance in China, these findings are expected to enhance access to financial services in urban and rural areas for more inclusive and sustainable futures. Full article
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16 pages, 3999 KiB  
Article
Genome-Wide Identification, Expression Profile, and Alternative Splicing Analysis of CAMTA Family Genes in Cucumber (Cucumis sativus L.)
by Rong Gao, Yanyan Luo, Fahong Yun, Xuetong Wu, Peng Wang and Weibiao Liao
Agronomy 2021, 11(9), 1827; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091827 - 12 Sep 2021
Cited by 15 | Viewed by 2150
Abstract
The calmodulin-binding transcription activator (CAMTA), as one of the most distinctive families of transcription factors, plays an important role in plant growth and development and in the stress response. However, it is currently unknown whether CAMTA exists in cucumbers and what [...] Read more.
The calmodulin-binding transcription activator (CAMTA), as one of the most distinctive families of transcription factors, plays an important role in plant growth and development and in the stress response. However, it is currently unknown whether CAMTA exists in cucumbers and what its function is. In this study, we first identified four CAMTA genes in the cucumber genome using a genome-wide search method. Subsequently, we analyzed their physical and chemical properties, gene structure, protein domains, and phylogenetic relationships. The results show that the structure of CsCAMTAs is similar to that of other plants, and a phylogenetic analysis divides them into three groups. The analysis of cis-acting elements shows that most CsCAMTAs contain a variety of hormones and stress-related elements. The RT-PCR analysis shows that CsCAMTAs have different expression levels in different tissues and can be induced by IAA, ABA, MeJA, NaCl, and PEG. Finally, we analyzed the expression pattern of CsCAMTAs’ alternative spliceosomes under salt and drought stress. The results show that the expression levels of the different spliceosomes are affected by the type of stress and the duration of stress. These data indicate that CsCAMTAs participate in growth and development and in the stress response in cucumbers, a finding which lays the foundation for future CsCAMTAs’ functional research. Full article
(This article belongs to the Special Issue Breeding, Genetics, and Genomic of the Genus Cucumis)
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26 pages, 7539 KiB  
Article
Temperature Dependences of IR Spectra of Humic Substances of Brown Coal
by Dmitry S. Volkov, Olga B. Rogova and Mikhail A. Proskurnin
Agronomy 2021, 11(9), 1822; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091822 - 11 Sep 2021
Cited by 21 | Viewed by 3343
Abstract
The capabilities of temperature-monitored IR spectroscopy for studying the organic matter and mineral composition of humic substances (HS) were tested. Temperature dependences of the mid-IR spectra of humic substances heated in the air in the range 25–215 °C (298–488 K, with a step [...] Read more.
The capabilities of temperature-monitored IR spectroscopy for studying the organic matter and mineral composition of humic substances (HS) were tested. Temperature dependences of the mid-IR spectra of humic substances heated in the air in the range 25–215 °C (298–488 K, with a step of 2.5 °C)—for three commercially available samples isolated from brown coal (leonardite)—were performed. The characteristic bands were identified, and their changes in band maxima positions and intensities were compared. From the viewpoint of interpretation of HS components, the spectra were divided into regions of quartz lattice region (800–260 cm−1), quartz overtone region (1270–800 cm−1), humic substance organic matter region (1780–1270 cm−1), quartz combination region (2800–1780 cm−1), CH-speciation region (3100–2800 cm−1), and hydrogen-speciation region (4000–3100 cm−1) thus selected to contain the dominating type of bands. For the first time, a reversible change in the frequencies of the band maxima in IR spectra upon heating was observed, which can be interpreted as forming structures with a particular order in the studied humic substances in the dry state. For a single sample, both the band-shift scale and the functional dependence of the various bands on temperature differ significantly. The approach differentiates crystalline quartz bands, amorphous silica, and HSOM/surface groups experiencing a different temperature behavior of the band maxima and their intensities. Band-maximum temperature dependence can be considered more stable to changes in experimental conditions than band maxima at a single temperature, thus providing a more detailed HS structure analysis without HS decomposition or destruction. Full article
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20 pages, 2929 KiB  
Article
PGPR-Mediated Plant Growth Attributes and Metal Extraction Ability of Sesbania sesban L. in Industrially Contaminated Soils
by Nida Zainab, Amna, Amir Abdullah Khan, Muhammad Atif Azeem, Baber Ali, Tongtong Wang, Fuchen Shi, Suliman Mohammed Alghanem, Muhammad Farooq Hussain Munis, Mohamed Hashem, Saad Alamri, Arafat Abdel Hamed Abdel Latef, Omar M. Ali, Mona H. Soliman and Hassan Javed Chaudhary
Agronomy 2021, 11(9), 1820; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091820 - 10 Sep 2021
Cited by 87 | Viewed by 5615
Abstract
The release of harmful wastes via different industrial activities is the main cause of heavy metal toxicity. The present study was conducted to assess the effects of heavy metal stress on the plant growth traits, antioxidant enzyme activities, chlorophyll content and proline content [...] Read more.
The release of harmful wastes via different industrial activities is the main cause of heavy metal toxicity. The present study was conducted to assess the effects of heavy metal stress on the plant growth traits, antioxidant enzyme activities, chlorophyll content and proline content of Sesbania sesban with/without the inoculation of heavy-metal-tolerant Bacillus gibsonii and B. xiamenensis. Both PGP strains showed prominent ACC-deaminase, indole acetic acid, exopolysaccharides production and tolerance at different heavy metal concentrations (50–1000 mg/L). Further, in a pot experiment, S. sesban seeds were grown in contaminated and noncontaminated soils. After harvesting, plants were used for the further analysis of growth parameters. The experiment comprised of six different treatments. The effects of heavy metal stress and bacterial inoculation on the plant root length; shoot length; fresh and dry weight; photosynthetic pigments; proline content; antioxidant activity; and absorption of metals were observed at the end of the experiment. The results revealed that industrially contaminated soils distinctly reduced the growth of plants. However, both PGPR strains enhanced the root length up to 105% and 80%. The shoot length was increased by 133% and 75%, and the fresh weight was increased by 121% and 129%. The proline content and antioxidant enzymes posed dual effects on the plants growing in industrially contaminated soil, allowing them to cope with the metal stress, which enhanced the plant growth. The proline content was increased up to 190% and 179% by the inoculation of bacterial strains. Antioxidant enzymes, such as SOD, increased to about 216% and 245%, while POD increased up to 48% and 49%, respectively. The results clearly show that the utilized PGPR strains might be strong candidates to assist S. sesban growth under heavy metal stress conditions. We highly suggest these PGPR strains for further implementation in field experiments. Full article
(This article belongs to the Special Issue Crop Physiological Responses to Abiotic Stress Factors)
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18 pages, 2087 KiB  
Article
Smart Farm Irrigation: Model Predictive Control for Economic Optimal Irrigation in Agriculture
by Gabriela Cáceres, Pablo Millán, Mario Pereira and David Lozano
Agronomy 2021, 11(9), 1810; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091810 - 9 Sep 2021
Cited by 20 | Viewed by 4789
Abstract
The growth of the global population, together with climate change and water scarcity, has made the shift towards efficient and sustainable agriculture increasingly important. Undoubtedly, the recent development of low-cost IoT-based sensors and actuators offers great opportunities in this direction since these devices [...] Read more.
The growth of the global population, together with climate change and water scarcity, has made the shift towards efficient and sustainable agriculture increasingly important. Undoubtedly, the recent development of low-cost IoT-based sensors and actuators offers great opportunities in this direction since these devices can be easily deployed to implement advanced monitoring and irrigation control techniques at a farm scale, saving energy and water and decreasing costs. This paper proposes an economic and periodic predictive controller taking advantage of the irrigation periodicity. The goal of the controller is to find an irrigation technique that optimizes water and energy consumption while ensuring adequate levels of soil moisture for crops, achieving the maximum crop yield. For this purpose, the developed predictive controller makes use of soil moisture data at different depths, and it formulates a constrained optimization problem that considers energy and water costs, crop transpiration, and an accurate dynamical nonlinear model of the water dynamics in the soil, reflecting the reality. This controller strategy is compared with a classical irrigation strategy adopted by a human expert in a specific case study, demonstrating that it is possible to obtain significant reductions in water and energy consumption without compromising crop yields. Full article
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20 pages, 484 KiB  
Article
Evaluation of Drought Tolerance of Some Wheat (Triticum aestivum L.) Genotypes through Phenology, Growth, and Physiological Indices
by M. Kaium Chowdhury, M. A. Hasan, M. M. Bahadur, Md. Rafiqul Islam, Md. Abdul Hakim, Muhammad Aamir Iqbal, Talha Javed, Ali Raza, Rubab Shabbir, Sobhy Sorour, Norhan E. M. Elsanafawy, Sultana Anwar, Saud Alamri, Ayman EL Sabagh and Mohammad Sohidul Islam
Agronomy 2021, 11(9), 1792; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091792 - 7 Sep 2021
Cited by 58 | Viewed by 7514
Abstract
Increasing human population and changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high yielding drought tolerant genotypes remains a proficient approach to cope with these challenges. To offer a methodology [...] Read more.
Increasing human population and changing climate, which have given rise to frequent drought spells, pose a serious threat to global food security, while identification of high yielding drought tolerant genotypes remains a proficient approach to cope with these challenges. To offer a methodology for the evaluation of the drought-tolerant wheat genotypes based on the pheno-physiological traits, a field experiment was executed, entailing four wheat genotypes viz. BARI Gom 26, BAW 1158, BAW 1167, and BAW 1169 and two water conditions viz. control treatment (three times irrigation at 20, 50, and 70 DAS, i.e., 100% field capacity) and stressed treatment (no irrigation during the entire growing season). The results revealed that drought stress drastically reduced the days to booting, heading, anthesis and physiological maturity, relative water content (RWC), chlorophyll content, canopy temperature depression (CTD), and photo-assimilates-spike dry matter (SDM), grains spike−1 and grain yield of all wheat genotypes. In addition, the genotypes BAW 1167 and BARI Gom 26 remained more prone to adverse effects of drought as compared to BAW 1169 and BAW 1158. Furthermore, DS induced biosynthesis of compatible solutes such as proline, especially in BAW 1169, which enabled plants to defend against oxidative stress. It was inferred that BAW 1169 remained superior by exhibiting the best adaptation as indicated by the maximum relative values of RWC, total chlorophyll, CTD, proline content, SDM, grains spike−1, and grain yield of wheat. Thus, based on our findings, BAW 1169 may be recommended for general adoption and utilization in future wheat breeding programs aimed at developing potent drought-tolerant wheat genotypes to ensure food security on a sustainable basis. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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17 pages, 1481 KiB  
Article
Soil Test Based Fertilizer Application Improves Productivity, Profitability and Nutrient Use Efficiency of Rice (Oryza sativa L.) under Direct Seeded Condition
by Vijay Kant Singh, Poonam Gautam, Gangadhar Nanda, Salwinder Singh Dhaliwal, Biswajit Pramanick, Shiv Singh Meena, Walaa F. Alsanie, Ahmed Gaber, Samy Sayed and Akbar Hossain
Agronomy 2021, 11(9), 1756; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091756 - 31 Aug 2021
Cited by 32 | Viewed by 5590
Abstract
A field investigation on direct seeded rice (DSR) was carried out in the two consecutive rice growing seasons of 2017 and 2018 at Pantnagar, Uttarakhand, India for the development and validation of soil test crop response (STCR) to fertilizer and for assessing the [...] Read more.
A field investigation on direct seeded rice (DSR) was carried out in the two consecutive rice growing seasons of 2017 and 2018 at Pantnagar, Uttarakhand, India for the development and validation of soil test crop response (STCR) to fertilizer and for assessing the performance of STCR-treatments as compared to the general recommended dose (GRD) in terms of yield, nutrient uptake and use efficiency, and the economics of DSR. For producing 1 Mg of rice-grain, the required nutrients (N, P, and K) were 2.01 kg, 0.44 kg, and 3.06 kg; the contribution from the soil was 22.05%, 37.34%, and 41.48%; from applied farmyard manure 23.25%, 28.34%, and 16.80%, from fertilizer 38.08%, 49.93%, and 252.98%; and from fertilizer with FYM 44.83%, 60.57%, and 278.70%; for N, P, and K, respectively. The STCR approach, with or without FYM, at both the target yields (4.5 Mg ha−1 and 5.0 Mg ha−1) markedly enhanced the grain yield (20.2% to 32.3%) and production efficiency over the GRD. It also exhibited a higher NPK uptake and use efficiency, along with better profitability, than the GRD. Therefore, the STCR-targeted yield approach could improve the yield, economics, and efficiency of nutrient use for direct seeded rice. Full article
(This article belongs to the Special Issue Cropping Systems and Agronomic Management Practices of Field Crops)
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18 pages, 1631 KiB  
Article
Utilization Efficiency of Growth Regulators in Wheat under Drought Stress and Sandy Soil Conditions
by Fathy M. A. El-Saadony, Yasser S. A. Mazrou, Ahmed E. A. Khalaf, Ahmed M. A. El-Sherif, Hany S. Osman, Emad M. Hafez and Mohamed A. M. Eid
Agronomy 2021, 11(9), 1760; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091760 - 31 Aug 2021
Cited by 9 | Viewed by 2966
Abstract
Drought stress and nutrient status are highly important for plant growth and productivity. Two field experiments were conducted during two consecutive seasons (2017–2018 and 2018–2019) at El-Molak, Abo-Hammad, Sharkia, Egypt. This work was conducted under sandy soil conditions to evaluate the effects of [...] Read more.
Drought stress and nutrient status are highly important for plant growth and productivity. Two field experiments were conducted during two consecutive seasons (2017–2018 and 2018–2019) at El-Molak, Abo-Hammad, Sharkia, Egypt. This work was conducted under sandy soil conditions to evaluate the effects of foliar application with growth regulators (PGRs) such as cycocel (CCC), applied at 0, 500, or 1000 mg L−1, and/or salicylic acid (SA), applied at 0, 0.05, or 0.1 mM on the productivity as well as improving drought tolerance of three wheat cultivars, i.e., Gemmeiza 11, Misr 1, and Giza 171 under three irrigation intervals, i.e., 10, 15, and 20 days. Foliar spray was given at 35 and 50 days after planting (DAP). The obtained results showed that mean squares as a result of the main effect and first- and second-order interactions were significant (p ≤ 0.01) for all studied traits. The application of SA increased total chlorophyll content and flag leaf area (cm2) while the number of days to 50% heading was decreased; however, the number of spikes m−2, protein and proline contents were increased with the application of CCC. The cultivar Misr 1 outperformed the other cultivars in the most studied traits. Estimates of heritability in the broad sense (h2b) were, on average, higher in five physiological traits than other agronomic traits, and the highest estimate of h2b (95.1%) was shown by the number of days to 50% heading followed by protein content (91.90%). Among the interactions between irrigation and growth regulators, the I(10) × SA(0.1) recorded the highest flag leaf area (cm2), SPAD value, number of grains spike−1, 1000-grain weight (g), and grain yield (t ha−1). Among the interactions between irrigation and cultivars, the I(10) × Misr 1 recorded the highest flag leaf area (cm2), SPAD value, number of grains spike−1, and grain yield (t ha−1). Among the interactions among irrigation, growth regulators and cultivars, the I(10) × SA(0.1) × Misr 1 recorded the highest flag leaf area (cm2), number of grains spike−1, 1000-grain weight (g), and grain yield (t ha−1). Correlation coefficient between grain yield (t ha−1) and each of the number of days to 50% heading, flag leaf area, total chlorophyll content, number of spikes m−2, number of grains spike−1, and 1000-grain weight was positive and significant. Three main factors for the studied variables were created from the application of the factor analysis technique. Grain yield ha−1 (Y) can be predicted by the method of forwarding stepwise through applying the automatic linear regression analysis. Besides, the best prediction equation of grain yield ha−1 (Y) was formulated as: Ỷ = −14.36 + 0.11 number of grains spike−1 (NGS) + 0.09 1000-grain weight (THW) + 0.04 number of spike m−2 (NSm) + 0.03 days to 50% heading (DF) + 0.02 total chlorophyll content (TC) with adjusted-R2 (87.33%). Full article
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12 pages, 3153 KiB  
Article
The Effect of Treating String Bean Pods with Modified Atmosphere Packaging and UV-C Irradiation on Their Storage Life
by Jolanta Franczuk, Robert Rosa, Anna Zaniewicz-Bajkowska and Agnieszka Ginter
Agronomy 2021, 11(9), 1747; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091747 - 30 Aug 2021
Cited by 1 | Viewed by 2240
Abstract
The aim of the experiment was to determine the optimal treatment of string bean pods, prolonging their storage life. To this end, the effect of modified atmosphere packaging in Xtend® bags (CH-49) and UV-C radiation on the quality of string beans ‘Unidor’ [...] Read more.
The aim of the experiment was to determine the optimal treatment of string bean pods, prolonging their storage life. To this end, the effect of modified atmosphere packaging in Xtend® bags (CH-49) and UV-C radiation on the quality of string beans ‘Unidor’ in cold storage was studied. Observations of the pods and their measurements were made after 14 and 28 days and chemical analyses 14 days after irradiation exposure and storage at 2–4 °C. The tests were conducted in laboratory conditions in a completely randomized design. Storing bean pods in Xtend® bags significantly increased the weight and umber of pods fit for consumption, compared to those stored in bulk. However, the content of dry matter, total sugars, and protein in pods stored in Xtend® bags decreased. Irradiation, regardless of the exposure time and the distance of lamps from the surface, contributed to an increase in the weight and number of pods suitable for consumption after 14 and 28 days. After 14 days irradiated pods contained more dry matter, L-ascorbic acid, polyphenols and flavonoids. After UV-C irradiation for 600 s with lamps at a height of 40 cm pods in Xtend® bags responded with the most favorable protein content. Full article
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18 pages, 10934 KiB  
Article
Dihydroisocoumarin Content and Phenotyping of Hydrangea macrophylla subsp. serrata Cultivars under Different Shading Regimes
by Marcel Dieter Moll, Alena Sophia Vieregge, Charis Wiesbaum, Maria Blings, Frederik Vana, Silke Hillebrand, Jakob Ley, Thorsten Kraska and Ralf Pude
Agronomy 2021, 11(9), 1743; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091743 - 30 Aug 2021
Cited by 5 | Viewed by 3059
Abstract
Hortensias (Hydrangea macrophylla L.) are well known as ornamental plants with their impressive flowers. Besides being an ornamental plant, some hortensia species contain constituents of nutritional and pharmaceutical interest. In this context, H. macrophylla subsp. serrata contains dihydroisocoumarins (DHCs), in particular hydrangenol [...] Read more.
Hortensias (Hydrangea macrophylla L.) are well known as ornamental plants with their impressive flowers. Besides being an ornamental plant, some hortensia species contain constituents of nutritional and pharmaceutical interest. In this context, H. macrophylla subsp. serrata contains dihydroisocoumarins (DHCs), in particular hydrangenol (HG) and phyllodulcin (PD), which determine produce quality. For the successful cultivation of H. macrophylla subsp. serrata, shading may be required. The response of H. macrophylla subsp. serrata as a source for DHCs was investigated in two growing seasons using three different cultivars (‘Amagi Amacha’, ‘Oamacha’ and ‘Odoriko Amacha’) under three different light conditions: no shade (100% photosynthetic active radiation, PAR), partial (72% PAR) and full shading (36% PAR). The shading regimes had no significant effect on dihydroisocoumarin content in leaf dry matter in each single cultivar. However, ‘Amagi Amacha’ and ‘Oamacha’ yielded significantly higher PD content in comparison to ‘Odoriko Amacha’, which showed, in contrast, the significantly highest HG content. The total biomass was not significantly affected by the shading regime, but slightly higher biomass was observed under partially shaded and full-shade conditions. Hyperspectral vegetation indices (VIs) and color measurements indicate less vital plants under no shade conditions. While lighting is an important growth factor for hortensia production, DHC is cultivar dependent. Full article
(This article belongs to the Special Issue A New Decade of Horticultural and Medicinal Plants Cultivation)
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13 pages, 904 KiB  
Article
Adoption of Conservation Agriculture in Rwanda: A Case Study of Gicumbi District Region
by Yves Theoneste Murindangabo, Marek Kopecký and Petr Konvalina
Agronomy 2021, 11(9), 1732; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091732 - 29 Aug 2021
Cited by 7 | Viewed by 6862
Abstract
Conservation agriculture (CA) is described as a farming system that is founded around three principles: minimum soil disturbance (reduced or no tillage), keeping a permanent soil cover (with crop residues, cover crops or both) and plant species diversification (plant associations and sequences). Little [...] Read more.
Conservation agriculture (CA) is described as a farming system that is founded around three principles: minimum soil disturbance (reduced or no tillage), keeping a permanent soil cover (with crop residues, cover crops or both) and plant species diversification (plant associations and sequences). Little to no information has been documented about conservation agriculture adoption in developing countries, such as Rwanda, with especially no information about its hilly and climate-varying part to which the Gicumbi district belongs. This study is targeted towards ascertaining the level of CA adoption in the Gicumbi district in relation to the socioeconomic status of the farming population, to suggest the relevant strategies for accelerating CA adoption specific to this region. The sampling technique used was a non-discriminative, snowball-sampling one, eventually gathering data from 500 households in three sectors. Semi-structured interviews were conducted using household questionnaires. Adoption of CA was related to the knowledge acquired during training and hands-on work on demonstration plots. Some farm-level constraints found were little to no material, few extension services and market problems. The impacts attributed to the use of CA were soil and productivity improvement. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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20 pages, 17048 KiB  
Article
Estimation of Fruit Load in Australian Mango Orchards Using Machine Vision
by Nicholas Todd Anderson, Kerry Brian Walsh, Anand Koirala, Zhenglin Wang, Marcelo Henrique Amaral, Geoff Robert Dickinson, Priyakant Sinha and Andrew James Robson
Agronomy 2021, 11(9), 1711; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091711 - 27 Aug 2021
Cited by 18 | Viewed by 3931
Abstract
The performance of a multi-view machine vision method was documented at an orchard level, relative to packhouse count. High repeatability was achieved in night-time imaging, with an absolute percentage error of 2% or less. Canopy architecture impacted performance, with reasonable estimates achieved on [...] Read more.
The performance of a multi-view machine vision method was documented at an orchard level, relative to packhouse count. High repeatability was achieved in night-time imaging, with an absolute percentage error of 2% or less. Canopy architecture impacted performance, with reasonable estimates achieved on hedge, single leader and conventional systems (3.4, 5.0, and 8.2 average percentage error, respectively) while fruit load of trellised orchards was over-estimated (at 25.2 average percentage error). Yield estimations were made for multiple orchards via: (i) human count of fruit load on ~5% of trees (FARM), (ii) human count of 18 trees randomly selected within three NDVI stratifications (CAL), (iii) multi-view counts (MV-Raw) and (iv) multi-view corrected for occluded fruit using manual counts of CAL trees (MV-CAL). Across the nine orchards for which results for all methods were available, the FARM, CAL, MV-Raw and MV-CAL methods achieved an average percentage error on packhouse counts of 26, 13, 11 and 17%, with SD of 11, 8, 11 and 9%, respectively, in the 2019–2020 season. The absolute percentage error of the MV-Raw estimates was 10% or less in 15 of the 20 orchards assessed. Greater error in load estimation occurred in the 2020–2021 season due to the time-spread of flowering. Use cases for the tree level data on fruit load was explored in context of fruit load density maps to inform early harvesting and to interpret crop damage, and tree frequency distributions based on fruit load per tree. Full article
(This article belongs to the Special Issue In-Field Estimation of Fruit Quality and Quantity)
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28 pages, 4206 KiB  
Article
Spatio-Temporal Analysis of Drought Variability in Myanmar Based on the Standardized Precipitation Evapotranspiration Index (SPEI) and Its Impact on Crop Production
by Zin Mie Mie Sein, Xiefei Zhi, Faustin Katchele Ogou, Isaac Kwesi Nooni, Kenny T. C. Lim Kam Sian and Gnim Tchalim Gnitou
Agronomy 2021, 11(9), 1691; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091691 - 25 Aug 2021
Cited by 19 | Viewed by 4235
Abstract
Drought research is an important aspect of drought disaster mitigation and adaptation. For this purpose, we used the Standardized Precipitation Evapotranspiration Index (SPEI) to investigate the spatial-temporal pattern of drought and its impact on crop production. Using monthly precipitation (Precip) and temperature (Temp) [...] Read more.
Drought research is an important aspect of drought disaster mitigation and adaptation. For this purpose, we used the Standardized Precipitation Evapotranspiration Index (SPEI) to investigate the spatial-temporal pattern of drought and its impact on crop production. Using monthly precipitation (Precip) and temperature (Temp) data from 1986–2015 for 39 weather stations, the drought index was obtained for the time scale of 3, 6, and 12 months. The Mann–Kendall test was used to determine trends and rates of change. Precip and Temp anomalies were investigated using the regression analysis and compared with the drought index. The link between drought with large-scale atmospheric circulation anomalies using the Pearson correlation coefficient (R) was explored. Results showed a non-uniform spatial pattern of dryness and wetness which varied across Myanmar agro-ecological zones and under different time scales. Generally, results showed an increasing trend for the SPEI in the three-time scales, signifying a high tendency of decreased drought from 1986–2015. The fluctuations in dryness/wetness might linked to reduction crop production between 1986–1999 and 2005, 2008, 2010, 2013 cropping years. Results show relationship between main crops production and climate (teleconnection) factors. However, the low correlation values (i.e., <0.49) indicate the extent of the relationship within the natural variability. However, readers are urged to interpret this result cautiously as reductions in crop production may also be affected by other factors. We have demonstrated droughts evolution and trends using weather stations, thus providing useful information to aid policymakers in developing spatially relevant climate change adaptation and mitigation management plans for Myanmar. Full article
(This article belongs to the Special Issue Drought and Heat Stress Regulation on Crop Development and Yield)
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24 pages, 6435 KiB  
Article
Climate Variability and Change Affect Crops Yield under Rainfed Conditions: A Case Study in Gedaref State, Sudan
by Maysoon A. A. Osman, Joshua Orungo Onono, Lydia A. Olaka, Muna M. Elhag and Elfatih M. Abdel-Rahman
Agronomy 2021, 11(9), 1680; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091680 - 24 Aug 2021
Cited by 9 | Viewed by 5518
Abstract
It is projected that, on average, annual temperature will increase between 2 °C to 6 °C under high emission scenarios by the end of the 21st century, with serious consequences in food and nutrition security, especially within semi-arid regions of sub-Saharan Africa. This [...] Read more.
It is projected that, on average, annual temperature will increase between 2 °C to 6 °C under high emission scenarios by the end of the 21st century, with serious consequences in food and nutrition security, especially within semi-arid regions of sub-Saharan Africa. This study aimed to investigate the impact of historical long-term climate (temperature and rainfall) variables on the yield of five major crops viz., sorghum, sesame, cotton, sunflower, and millet in Gedaref state, Sudan over the last 35 years. Mann–Kendall trend analysis was used to determine the existing positive or negative trends in temperature and rainfall, while simple linear regression was used to assess trends in crop yield over time. The first difference approach was used to remove the effect of non-climatic factors on crop yield. On the other hand, the standardized anomaly index was calculated to assess the variability in both rainfall and temperature over the study period (i.e., 35 years). Correlation and multiple linear regression (MLR) analyses were employed to determine the relationships between climatic variables and crops yield. Similarly, a simple linear regression was used to determine the relationship between the length of the rainy season and crop yield. The results showed that the annual maximum temperature (Tmax) increased by 0.03 °C per year between the years 1984 and 2018, while the minimum temperature (Tmin) increased by 0.05 °C per year, leading to a narrow range in diurnal temperature (DTR). In contrast, annual rainfall fluctuated with no evidence of a significant (p > 0.05) increasing or decreasing trend. The yields for all selected crops were negatively correlated with Tmin, Tmax (r ranged between −0.09 and −0.76), and DTR (r ranged between −0.10 and −0.70). However, the annual rainfall had a strong positive correlation with yield of sorghum (r = 0.64), sesame (r = 0.58), and sunflower (r = 0.75). Furthermore, the results showed that a longer rainy season had significant (p < 0.05) direct relationships with the yield of most crops, while Tmax, Tmin, DTR, and amount of rainfall explained more than 50% of the variability in the yield of sorghum (R2 = 0.70), sunflower (R2 = 0.61), and millet (R2 = 0.54). Our results call for increased awareness among different stakeholders and policymakers on the impact of climate change on crop yield, and the need to upscale adaptation measures to mitigate the negative impacts of climate variability and change. Full article
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13 pages, 3507 KiB  
Article
Effects of Nitrification Inhibitors on Soil Nitrification and Ammonia Volatilization in Three Soils with Different pH
by Lei Cui, Dongpo Li, Zhijie Wu, Yan Xue, Furong Xiao, Lili Zhang, Yuchao Song, Yonghua Li, Ye Zheng, Jinming Zhang and Yongkun Cui
Agronomy 2021, 11(8), 1674; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081674 - 23 Aug 2021
Cited by 28 | Viewed by 4514
Abstract
The application of nitrification inhibitors (NIs) is considered to be an efficient way to delay nitrification, but the effect of NIs combinations on soil nitrification and ammonia (NH3) volatilization are not clear in soils with different pH values. In this study, [...] Read more.
The application of nitrification inhibitors (NIs) is considered to be an efficient way to delay nitrification, but the effect of NIs combinations on soil nitrification and ammonia (NH3) volatilization are not clear in soils with different pH values. In this study, we explored the effect of nitrapyrin (CP) and its combinations with 3, 4-dimethylepyrazole phosphate (DMPP), dicyandiamide (DCD) on the transformation of nitrogen, potential nitrification rate (PNR), and ammonia (NH3) volatilization in a 120-day incubation experiment with three different pH values of black soil. Treatments included no fertilizer (Control), ammonium sulfate (AS), AS+CP (CP), AS+CP+DMPP (CP+DMPP), and AS+CP+DCD (CP+DCD). The application of NIs significantly decreased NO3-N contents and potential nitrification rate (p < 0.05), while significantly increased NH4+-N contents (p < 0.05), especially CP+DCD and CP+DMPP were the most effective in the neutral and alkaline soils, respectively. In the acid soil, CP significantly increased total NH3 volatilization by 31%, while CP+DCD significantly reduced by 28% compared with AS. However, no significant difference was found in NH3 volatilization with and without NIs treatments (p > 0.05) in the neutral and alkaline soils. In conclusion, the combined nitrification inhibitors had the better efficiency in all three tested soils. CP+DCD and CP+DMPP are the most effective in inhibiting soil nitrification in the clay soils with higher pH value and lower organic matter, while CP+DCD had the potential in mitigating environment pollution by reducing N loss of NH3 volatilization in the loam soil with lower pH value and higher organic matter. It provided a theoretical basis for the application of high efficiency fertilizer in different soils. Further studies under field conditions are required to assess the effects of these nitrification inhibitors. Full article
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18 pages, 542 KiB  
Article
Alfalfa Established Successfully in Intercropping with Corn in the Midwest US
by Marisol T. Berti, Andrea Cecchin, Dulan P. Samarappuli, Swetabh Patel, Andrew W. Lenssen, Ken J. Moore, Samantha S. Wells and Maciej J. Kazula
Agronomy 2021, 11(8), 1676; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081676 - 23 Aug 2021
Cited by 13 | Viewed by 3383
Abstract
Integrating alfalfa (Medicago sativa L.) with corn (Zea mays L.) for grain will increase biodiversity, reduce the negative environmental impact of corn monoculture and increase farm profitability. The objectives of this research were to evaluate forage productivity and nutritive value, along [...] Read more.
Integrating alfalfa (Medicago sativa L.) with corn (Zea mays L.) for grain will increase biodiversity, reduce the negative environmental impact of corn monoculture and increase farm profitability. The objectives of this research were to evaluate forage productivity and nutritive value, along with stand establishment of alfalfa in a corn grain system in Iowa, Minnesota, and North Dakota. The experimental design was a randomized complete block with four replicates at each site. Treatments included were: sole corn (i.e., check; T1), sole alfalfa (T2), alfalfa intercropped into corn (T3), a prohexadione-treated alfalfa intercropped with corn (T4), and a spring-seeded alfalfa in the year after intercropping (T5), which was planted in plots with T1 the previous year. All sites had below normal rainfall in 2016 and 2017. Corn grain yield was significantly lower when intercropped with alfalfa (T3 and T4) compared with the check corn crop (no alfalfa, T1). Corn grain yield reduction ranged from 14.0% to 18.8% compared with the check (T1). Corn biomass yield was reduced by intercropped alfalfa (T3 and T4) by 15.9% to 25.8%. In the seeding year, alfalfa seasonal forage yield was significantly greater when corn competition was absent in all environments. The intercropped alfalfa from the previous season (T3 and T4) had almost double the forage yield than the alfalfa in the seeding year (spring-seeded alfalfa; T5). In the second production year, there were no meaningful forage yield differences (p > 0.05) across all treatments, indicating alfalfa in intercropping systems does not affect forage yield past the first production year. Prohexadione-calcium, a growth regulator, did not affect alfalfa stand density, forage yield and nutritive value. The forage nutritive value was dependent on harvest date not the alfalfa intercropping treatments. Results of our study suggest that establishing alfalfa with corn is feasible and can be a potential alternative for the upper Midwest region. However, when under drought conditions, this system might be less resilient since competition between alfalfa and corn for soil moisture will be intensified under drought or moisture-limited conditions, and this will likely depress corn grain yield. Research targeted to reintroduce perennial crops into the current dominant corn–soybean systems in the US Corn Belt is urgently needed to improve stability and resiliency of production systems. Full article
(This article belongs to the Special Issue Advances in Forages, Cover Crops, and Biomass Crops Production)
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18 pages, 9575 KiB  
Article
Magnesium transporter Gene Family: Genome-Wide Identification and Characterization in Theobroma cacao, Corchorus capsularis, and Gossypium hirsutum of Family Malvaceae
by Parviz Heidari, Abdullah, Sahar Faraji and Peter Poczai
Agronomy 2021, 11(8), 1651; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081651 - 19 Aug 2021
Cited by 41 | Viewed by 3366
Abstract
Magnesium (Mg) is an element involved in various key cellular processes in plants. Mg transporter (MGT) genes play an important role in magnesium distribution and ionic balance maintenance. Here, MGT family members were identified and characterized in three species of the plant family [...] Read more.
Magnesium (Mg) is an element involved in various key cellular processes in plants. Mg transporter (MGT) genes play an important role in magnesium distribution and ionic balance maintenance. Here, MGT family members were identified and characterized in three species of the plant family Malvaceae, Theobroma cacao, Corchorus capsularis, and Gossypium hirsutum, to improve our understanding of their structure, regulatory systems, functions, and possible interactions. We identified 18, 41, and 16 putative non-redundant MGT genes from the genome of T. cacao, G. hirsutum, and C. capsularis, respectively, which clustered into three groups the maximum likelihood tree. Several segmental/tandem duplication events were determined between MGT genes. MGTs appear to have evolved slowly under a purifying selection. Analysis of gene promoter regions showed that MGTs have a high potential to respond to biotic/abiotic stresses and hormones. The expression patterns of MGT genes revealed a possible role in response to P. megakarya fungi in T. cacao, whereas MGT genes showed differential expression in various tissues and response to several abiotic stresses, including cold, salt, drought, and heat stress in G. hirsutum. The co-expression network of MGTs indicated that genes involved in auxin-responsive lipid metabolism, cell wall organization, and photoprotection can interact with MGTs. Full article
(This article belongs to the Special Issue Omics Approaches for Crop Improvement)
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11 pages, 2850 KiB  
Article
Strawberry Living Mulch in an Organic Vineyard
by Davide Neri, Serena Polverigiani, Matteo Zucchini, Veronica Giorgi, Fabio Marchionni and Md Jebu Mia
Agronomy 2021, 11(8), 1643; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081643 - 18 Aug 2021
Cited by 17 | Viewed by 3570
Abstract
A living mulch system can provide beneficial biodiversified phytocoenoses and spatial competition against weeds; however, it may also compete for water with the main cultivated crop under Mediterranean climate conditions. Strawberries employed as living mulch in a rain-fed hill vineyard of central Italy [...] Read more.
A living mulch system can provide beneficial biodiversified phytocoenoses and spatial competition against weeds; however, it may also compete for water with the main cultivated crop under Mediterranean climate conditions. Strawberries employed as living mulch in a rain-fed hill vineyard of central Italy were evaluated for two years through a participative approach involving the farmer. A local wild strawberry was propagated by stolons to obtain small plantlets easily uprooted after the summer and then transplanted to a one-year-old vineyard. The densities of two and four strawberry plants per grapevine were compared with no living mulch in a randomized complete block design. A horizontal blade weeder was used once a year in all treatments. The results showed that strawberries as living mulch plus application of a blade weeder avoided the need for further soil tillage and assured a full soil cover during winter for both initial planting densities. The strawberry living mulch did not alter the grapevine transpiration during an incident of water stress in summer. Moreover, the yield per vine and the grape quality were comparable with those of the soil without living mulch. The growth of strawberry mulch was relevant in the area surrounding the vines. Furthermore, the living mulch guaranteed a constant soil cover reducing the risk for soil erosion while increasing the vineyard’s biological diversity. This may imply a higher resilience. Full article
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10 pages, 244 KiB  
Article
The Impact of Ensiling at Different Moisture Contents on Germinability and Viability of Selected Weed Species’ Seeds
by John W. Piltz, Kristy L. Bailes, Suzanne P. Boschma and Leslie A. Weston
Agronomy 2021, 11(8), 1639; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081639 - 17 Aug 2021
Cited by 3 | Viewed by 1860
Abstract
Weeds are an increasingly significant issue inhibiting agricultural production worldwide. Forage conservation could form part of an integrated weed management program if ensiling killed weed seeds. In Experiment 1, seeds of five grass (Hordeum spp., Bromus diandrus, Bromus hordeaceum, Lolium [...] Read more.
Weeds are an increasingly significant issue inhibiting agricultural production worldwide. Forage conservation could form part of an integrated weed management program if ensiling killed weed seeds. In Experiment 1, seeds of five grass (Hordeum spp., Bromus diandrus, Bromus hordeaceum, Lolium rigidum and Vulpia spp.) and two broad-leaved temperate weed species (Echium spp. and Raphanus raphanistrum), that were either untreated, ensiled in pasture (Trifolium subterranean/Lolium rigidum mixture) forage for a minimum of three months, underwent 48 h in sacco digestion in steers or ensiled prior to digestion were tested for germinability and viability. In Experiment 2, seeds of eight tropical weed species (Cenchrus ciliaris, Rumex spp., Bidens pilosa, Sorghum halepense, Urochloa panicaoides, Paspalum dilatatum, Brachiara eruciformis and Choris truncata) were ensiled in Sorghum bicolor forage. In Experiment 3, L. rigidum and R. raphanistrum seeds were ensiled in either Medicago sativa forage wilted to 336.9, 506.5 or 610.7 g/kg dry matter; or in chaff to which water or water plus acid was added at rates to achieve 350, 450 or 550 g/kg dry matter content with lactic plus acetic acid added in the ratio of 3:2 at 80, 45 or 10 g/kg DM, respectively. In Experiment 4, L. rigidum and R. raphanistrum seeds were ensiled in cotton wool to which water or water plus acid was added at the same rates as in Experiment 3. Germinability of all seeds following ensiling was substantially reduced or nil. The extent of the reduction varied with species and experiment. In sacco digestion reduced germinability in Experiment 1, but to a lesser extent than ensiling; while ensiling plus digestion reduced germination rates to 0%. Full article
(This article belongs to the Special Issue Integrated Weed Management Approaches and Decision Support Systems)
18 pages, 1529 KiB  
Article
Improvement of Soil Health and System Productivity through Crop Diversification and Residue Incorporation under Jute-Based Different Cropping Systems
by Mukesh Kumar, Sabyasachi Mitra, Sonali Paul Mazumdar, Bijan Majumdar, Amit Ranjan Saha, Shiv Ram Singh, Biswajit Pramanick, Ahmed Gaber, Walaa F. Alsanie and Akbar Hossain
Agronomy 2021, 11(8), 1622; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081622 - 16 Aug 2021
Cited by 29 | Viewed by 3030
Abstract
Crop diversity through residue incorporation is the most important method for sustaining soil health. A field study was conducted over five consecutive years (2012–2017) to see the impact of residue incorporartions in Inceptisol of eastern India. The main plot treatments had five cropping [...] Read more.
Crop diversity through residue incorporation is the most important method for sustaining soil health. A field study was conducted over five consecutive years (2012–2017) to see the impact of residue incorporartions in Inceptisol of eastern India. The main plot treatments had five cropping systems (CS), namely, fallow−rice−rice (FRR), jute−rice−wheat (JRW), jute−rice−baby corn (JRBc), jute−rice−vegetable pea (JRGp), jute−rice−mustard−mungbean/green gram (JRMMu), which cinsisted of four sub-plots with varied nutrient and crop residue management (NCRM) levels, namely crops with no residue +75% of the recommended dose of fertilizers (RDF) (F1R0), crops with the residue of the previous crops +75% RDF (F1R1), crops with no resiude +100% RDF (F2R0), and crops with residue +100% RDF (F2R1). The highest system productivity was obtained for JRBc (15.3 Mg·ha−1), followed by JRGp (8.81 Mg·ha−1) and JRMMu (7.61 Mg·ha−1); however, the highest sustainability index was found with the JRGp cropping system (0.88), followed by JRMMu (0.82). Among the NCRMs, the highest productivity (8.78 Mg·ha−1) and sustainability index (0.83) were recorded in F2R1. Five soil parameters, namely, bulk density, available K, urease activity, dehydrogenase activity, and soil microbial biomass carbon (SMBC), were used in the minimum data-set (MDS) for the calculation of the soil quality index (SQI). The best attainment of SQI was found in the JRGp system (0.63), closely followed by the JRMMu (0.61) cropping system. Full article
(This article belongs to the Special Issue Cropping Systems and Agronomic Management Practices of Field Crops)
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14 pages, 1870 KiB  
Article
Consortia of Plant-Growth-Promoting Rhizobacteria Isolated from Halophytes Improve Response of Eight Crops to Soil Salinization and Climate Change Conditions
by Susana Redondo-Gómez, Jennifer Mesa-Marín, Jesús A. Pérez-Romero, Javier López-Jurado, Jesús V. García-López, Vicente Mariscal, Fernando P. Molina-Heredia, Eloisa Pajuelo, Ignacio D. Rodríguez-Llorente, Timothy J. Flowers and Enrique Mateos-Naranjo
Agronomy 2021, 11(8), 1609; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081609 - 13 Aug 2021
Cited by 27 | Viewed by 3742
Abstract
Soil salinization is an environmental problem that adversely affects plant growth and crop productivity worldwide. As an alternative to the conventional approach of breeding salt-tolerant plant cultivars, we explored the use of plant-growth-promoting rhizobacteria (PGPR) from halophytic plants to enhance crop growth under [...] Read more.
Soil salinization is an environmental problem that adversely affects plant growth and crop productivity worldwide. As an alternative to the conventional approach of breeding salt-tolerant plant cultivars, we explored the use of plant-growth-promoting rhizobacteria (PGPR) from halophytic plants to enhance crop growth under saline conditions. Here, we report the effect of five PGPR consortia from halophytes on the growth of eight (alfalfa, flax, maize, millet, rice, strawberry, sunflower, and wheat) of the crops most commonly produced on salinized soils worldwide. To test the efficiency of halotolerant consortia, we designed a complex environmental matrix simulating future climate-change scenarios, including increased CO2 levels and temperature. Overall, biofertilizers enhanced growth of most crops with respect to non-inoculated control plants under different CO2 concentrations (400/700 ppm), temperatures (25/+4 °C), and salinity conditions (0 and 85 mM NaCl). Biofertilizers counteracted the detrimental effect of salinity on crop growth. Specifically, strawberry and rice showed the greatest positive additive response to inoculation in the presence of salt; above-ground biomasses were 35% and 3% greater, respectively, than their respective control grown without salt. Furthermore, depending on the interaction of environmental factors (salinity × CO2 × temperature) analyzed, the results varied—influencing the most effective biofertilizer determined for each crop now, or in the future. Our findings highlight the importance of conducting studies that consider stress interaction for realistic assessments of the potential of biofertilizers in a climate-changed world. Full article
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14 pages, 609 KiB  
Article
Combined Influence of Grafting and Type of Protected Environment Structure on Agronomic and Physiological Traits of Single- and Cluster-Fruit-Bearing Cucumber Hybrids
by Pratapsingh Suresh Khapte, Pradeep Kumar, Nav Raten Panwar, Uday Burman, Youssef Rouphael and Praveen Kumar
Agronomy 2021, 11(8), 1604; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081604 - 12 Aug 2021
Cited by 6 | Viewed by 2130
Abstract
Protected vegetable cultivation is a fast-growing sector in which grafting plays a crucial role for success. Cucumber is predominantly grown under protected conditions. The popular slicing (mini) cucumber comprises two segments, single- and cluster-fruit-bearing. In the present study, the performance of select fruit-bearing [...] Read more.
Protected vegetable cultivation is a fast-growing sector in which grafting plays a crucial role for success. Cucumber is predominantly grown under protected conditions. The popular slicing (mini) cucumber comprises two segments, single- and cluster-fruit-bearing. In the present study, the performance of select fruit-bearing hybrids grafted as scions onto commercial Cucurbita hybrid rootstock ‘NS-55’ was evaluated under three different low-cost protected structures in arid regions. With respect to type of protected structure, cucumber performance was superior under a naturally ventilated polyhouse (NVP) than an insect net house (INH) or a shade net house (SNH). Micro-climate parameters inside NVP (air temperature, RH and PAR) were more congenial for cucumber than those in net houses, thereby facilitating improved physiology (chlorophyll fluorescence, chlorophyll and plant water potential) and leaf mineral status. Grafting invariably improved growth and yield parameters under all protected structures. Overall plant performance was better in the grafted cluster-fruit-bearing hybrid ‘Terminator’ than the single-fruit-bearing hybrid ‘Nefer’ or their non-grafted counterparts. Furthermore, NVP was found to be superior to net houses for water productivity, and grafted plants were more water use efficient than their counterpart non-grafted plants. Thus, NVP can be considered a suitable low-cost protected structure in conjunction with grafting to boost cucumber crop and water productivity in arid regions. Full article
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15 pages, 501 KiB  
Article
Lime and Organic Manure Amendment Enhances Crop Productivity of Wheat–Mungbean–T. Aman Cropping Pattern in Acidic Piedmont Soils
by Mohammad Rafiqul Islam, Rounok Jahan, Shihab Uddin, Israt Jahan Harine, Mohammad Anamul Hoque, Sabry Hassan, Mohamed M. Hassan and Mohammad Anwar Hossain
Agronomy 2021, 11(8), 1595; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081595 - 11 Aug 2021
Cited by 14 | Viewed by 3663
Abstract
Soil acidity is a major problem when it comes to improving crop productivity and nutrient uptake. This experiment was therefore conducted at a farmer’s field—Nalitabari Upazila under AEZ 22 (northern and eastern Piedmont plains) to evaluate the effects of lime and organic manure [...] Read more.
Soil acidity is a major problem when it comes to improving crop productivity and nutrient uptake. This experiment was therefore conducted at a farmer’s field—Nalitabari Upazila under AEZ 22 (northern and eastern Piedmont plains) to evaluate the effects of lime and organic manure (OM) amendment on crop productivity and nutrient uptake of the wheat–mungbean–T. Aman cropping pattern in acidic soils of northern and eastern Piedmont plains. The experiment was laid out in a randomized complete block design with three replications. There were nine treatments applied, varying doses of lime (dololime at the rate of 1 and 2 t ha−1), OM (cow dung at the rate of 5 t ha−1, poultry manure at the rate of 3 t ha−1) and a lime–OM combination to the first crop; T. Aman and its residual effects were evaluated in the succeeding second crop, wheat, and the third crop, mungbean. Results demonstrate that application of lime and organic manure to soil had significant effects on the first crop. However, the effects of lime and organic manure were more pronounced in the second and third crops. The increase in grain yield over control ranged from 0.24 to 13.44% in BINA dhan7. However, it varied from 10.14 to 54.38% in BARI Gom30 and 40 to 161.67% in BARI Mung6. The straw yields of the crops also followed a similar trend. The N, P, K, and S uptake by grain and straw of T. Aman, wheat, and mungbean were influenced significantly by the combined application of lime and organic manure. Sole or combined application of lime and manure amendment significantly improved nutrient availability and soil quality. Therefore, application of lime in combination with manure can be practiced for uplifting the crop productivity and improving soil quality in acidic Piedmont soils of northern and eastern Piedmont plains. Full article
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18 pages, 2847 KiB  
Article
The Effect of Trichoderma citrinoviride Treatment under Salinity Combined to Rhizoctonia solani Infection in Strawberry (Fragaria x ananassa Duch.)
by Askim Hediye Sekmen Cetinel, Azime Gokce, Erhan Erdik, Barbaros Cetinel and Nedim Cetinkaya
Agronomy 2021, 11(8), 1589; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081589 - 10 Aug 2021
Cited by 15 | Viewed by 3274
Abstract
Trihoderma citrinoviride protects plants from diseases by functioning as antagonists of many pathogenic fungi or by triggering the antioxidant defense system in plants. In the present study, to uncover the possible alleviative role of Trichoderma against salinity and Rhizoctonia solani infection, strawberry plants [...] Read more.
Trihoderma citrinoviride protects plants from diseases by functioning as antagonists of many pathogenic fungi or by triggering the antioxidant defense system in plants. In the present study, to uncover the possible alleviative role of Trichoderma against salinity and Rhizoctonia solani infection, strawberry plants were pretreated Trichoderma citrinoviride and then subjected to salinity, R. solani and combined salinity and R. solani. The effect of T. citrinoviride on the alleviation of the effects of salt stress and Rhizoctonia solani infection was investigated by analysing leaf dry weight, PSII efficiency, and the activity of some antioxidant enzymes in the leaves of strawberry plants. T. citrinoviride improved competitive capability against salinity and R. solani infection. It showed 79% inhibition of the growth of pathogen R. solani. T. citrinoviride reduced 63% of the severity of disease in the leaves. Trichoderma pretreatment maximized plant dry weight. The T. citrinoviride-pretreated plants showed higher levels of PSII efficiency (Fv/Fm). Decreased lipid peroxidation and H2O2 accumulation compared to untreated seedlings under salt stress and R. solani infection was observed. Trichoderma-pretreated and –untreated plants respond differently to salt stress and R. solani infection by means of antioxidant defense. As compared to untreated seedlings, treated seedlings showed significantly lower activities of antioxidant enzymes, superoxide dismutase (SOD), peroxidase (POX), cell wall peroxidase (CWPOX) under salt stress and R. solani infection, indicating that treated seedlings might sense lower stress as compared to untreated seedlings. The study reports the effective adaptive strategy and potential of T. citrinoviride in alleviating the negative impact of salt stress and R. solani infection in strawberry. Full article
(This article belongs to the Special Issue Role of Biological Amendments in Abiotic Stress Tolerance of Crops)
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12 pages, 14420 KiB  
Article
An Efficient Structure of an Agrophotovoltaic System in a Temperate Climate Region
by Sojung Kim, Sumin Kim and Chang-Yong Yoon
Agronomy 2021, 11(8), 1584; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081584 - 9 Aug 2021
Cited by 28 | Viewed by 4706
Abstract
The aim of this study was to identify an efficient agrophotovoltaic (APV) system structure for generating electricity from solar radiation without causing an adverse impact on crop growth. In a temperate climate region, it is critical to design an APV system with appropriate [...] Read more.
The aim of this study was to identify an efficient agrophotovoltaic (APV) system structure for generating electricity from solar radiation without causing an adverse impact on crop growth. In a temperate climate region, it is critical to design an APV system with appropriate structure with the maximum amount of electricity generation because, unlike in desert areas, strong solar radiation is only available for a few hours a day. In this study, APV systems with three different shading ratios (i.e., 32%, 25.6%, and 21.3%) were considered, and the optimum structure in terms of electricity efficiency and profitability was investigated via nonlinear programming. Moreover, an estimation model of electricity generation was developed via a polynomial regression model based on remote sensing data given by the APV system located at Jeollanamdo Agricultural Research and Extension Services in South Korea. To evaluate the impact of the APV on crop production, five different grain crops—sesame (Sesamum indicum), mung bean (Vigna radiata), red bean (Vigna angularis), corn (Zea mays), and soybean (Glycine max)—were cultivated in the system. As a result, the proposed optimization model successfully identified the best APV system structure without reducing existing crop production. Full article
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12 pages, 682 KiB  
Article
Efficiency of Basil Essential Oil Antimicrobial Agents under Different Shading Treatments and Harvest Times
by Zoran S. Ilić, Lidija Milenković, Ljubomir Šunić, Nadica Tmušić, Jasna Mastilović, Žarko Kevrešan, Ljiljana Stanojević, Bojana Danilović and Jelena Stanojević
Agronomy 2021, 11(8), 1574; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081574 - 6 Aug 2021
Cited by 16 | Viewed by 4221
Abstract
The aim of this study was to determine the antimicrobial activity of essential oils obtained from sweet basil (Ocimum basilicum L. cv. ‘Genovese’) cultivated in the open field under different shading conditions (red, blue, and pearl nets with a shade index of [...] Read more.
The aim of this study was to determine the antimicrobial activity of essential oils obtained from sweet basil (Ocimum basilicum L. cv. ‘Genovese’) cultivated in the open field under different shading conditions (red, blue, and pearl nets with a shade index of 50% and full sunlight exposure (control plants)), harvested at different times. The antimicrobial activity of basil essential oils (BEOs) obtained from all samples was determined for four microorganisms, while determinations for an additional five microorganisms included samples from non-shaded plants, plants grown under red and pearl nets, and second harvest of plants grown under blue net. Basil essential oil exhibited antimicrobial activity surpassing the activity of relevant commercial antibiotics regardless of growing conditions in the case of B. cereus, K. pneumoniae and C. albicans, while superior antimicrobial activity was exhibited in the case of essential oils from plants grown under blue nets in the case of S. aureus, E. coli and P. vulgaris. The influence of the application of colored shading nets was highly significant (p < 0.01) in the cases of all analyzed microorganisms except C. albicans and P. aeruginosa, while the influence of harvest time was proven in the cases of all microorganisms except K. pneumoniae. ANOVA proved that antimicrobial activities are highly dependent on the methods of plant production, shading treatment, and harvest time. Obtained results are discussed in relation to previously determined composition and yield of essential oils from basil grown under shade nets and harvested in different periods. Full article
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14 pages, 995 KiB  
Article
Comprehensive Evaluation of Salt Tolerance in Rice (Oryza sativa L.) Germplasm at the Germination Stage
by Rui Zhang, Shahid Hussain, Yang Wang, Yonghao Liu, Qing Li, Yinglong Chen, Huanhe Wei, Pinglei Gao and Qigen Dai
Agronomy 2021, 11(8), 1569; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081569 - 5 Aug 2021
Cited by 22 | Viewed by 4004
Abstract
Salt stress reduces the yield and quality of rice. It is of great significance to screen out salt-tolerant varieties for the development and utilization of saline land. The study was carried out on 114 rice varieties; first, seven varieties were selected and treated [...] Read more.
Salt stress reduces the yield and quality of rice. It is of great significance to screen out salt-tolerant varieties for the development and utilization of saline land. The study was carried out on 114 rice varieties; first, seven varieties were selected and treated with different salt concentrations (0, 50, 85, 120, 155, 190, 225 mM), and seven traits, including germination energy, germination capacity, shoot length, root length, root number, plant fresh weight, and seedling vigor index, were measured. The salt concentration at which the sodium chloride injury index was 50% of the control was considered the optimal salt concentration. Second, 114 rice germplasms were carried out under an optimal salt concentration (120 mM). Then, principal component analysis, fuzzy function analysis, stepwise regression analysis, correlation analysis, and systematic cluster analysis were carried out on each parameter. There was a significant correlation between each parameter and the D-value, and the correlation coefficient between the seedling vigor index and D-value was the highest. D-value = − 0.272 + 1.335 × STI − SVI + 0.549 × STI − RN − 0.617 × STI-RL + 0.073 × STI − GE, R2 = 0.986. Using this equation, the sodium chloride tolerance of rice in the germination experiment could be quickly identified. This study showed that the seedling vigor index was a reliable parameter to identify the salinity tolerance of rice varieties. Five groups were obtained by classification at a Euclidean distance of 5. There were 8 highly salt-tolerant cultivars, 23 salt-tolerant cultivars, 42 cultivars with moderate salt tolerance, 33 salt-sensitive cultivars, and 8 highly salt-sensitive cultivars. In this study, we found that Riguang was the most salt-tolerant rice variety, and Xiangxuejing15 was the most salt-sensitive variety. Full article
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18 pages, 3004 KiB  
Article
Deep Learning-Based Growth Prediction System: A Use Case of China Agriculture
by Tamoor Khan, Hafiz Husnain Raza Sherazi, Mubashir Ali, Sukumar Letchmunan and Umair Muneer Butt
Agronomy 2021, 11(8), 1551; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081551 - 3 Aug 2021
Cited by 19 | Viewed by 4431
Abstract
Agricultural advancements have significantly impacted people’s lives and their surroundings in recent years. The insufficient knowledge of the whole agricultural production system and conventional ways of irrigation have limited agricultural yields in the past. The remote sensing innovations recently implemented in agriculture have [...] Read more.
Agricultural advancements have significantly impacted people’s lives and their surroundings in recent years. The insufficient knowledge of the whole agricultural production system and conventional ways of irrigation have limited agricultural yields in the past. The remote sensing innovations recently implemented in agriculture have dramatically revolutionized production efficiency by offering unparalleled opportunities for convenient, versatile, and quick collection of land images to collect critical details on the crop’s conditions. These innovations have enabled automated data collection, simulation, and interpretation based on crop analytics facilitated by deep learning techniques. This paper aims to reveal the transformative patterns of old Chinese agrarian development and fruit production by focusing on the major crop production (from 1980 to 2050) taking into account various forms of data from fruit production (e.g., apples, bananas, citrus fruits, pears, and grapes). In this study, we used production data for different fruits grown in China to predict the future production of these fruits. The study employs deep neural networks to project future fruit production based on the statistics issued by China’s National Bureau of Statistics on the total fruit growth output for this period. The proposed method exhibits encouraging results with an accuracy of 95.56% calculating by accuracy formula based on fruit production variation. Authors further provide recommendations on the AGR-DL (agricultural deep learning) method being helpful for developing countries. The results suggest that the agricultural development in China is acceptable but demands more improvement and government needs to prioritize expanding the fruit production by establishing new strategies for cultivators to boost their performance. Full article
(This article belongs to the Special Issue Applications of Deep Learning in Smart Agriculture)
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13 pages, 1428 KiB  
Article
Efficacy of Fungicides against Fusarium Head Blight Depends on the Timing Relative to Infection Rather than on Wheat Growth Stage
by Elisa González-Domínguez, Pierluigi Meriggi, Matteo Ruggeri and Vittorio Rossi
Agronomy 2021, 11(8), 1549; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081549 - 1 Aug 2021
Cited by 11 | Viewed by 3743
Abstract
Fungicides used to control Fusarium head blight (FHB) are commonly applied at the wheat growth stage considered to be most susceptible, i.e., anthesis. We compared the efficacy of the most commonly used fungicide groups that were applied following two strategies: (i) at pre-defined [...] Read more.
Fungicides used to control Fusarium head blight (FHB) are commonly applied at the wheat growth stage considered to be most susceptible, i.e., anthesis. We compared the efficacy of the most commonly used fungicide groups that were applied following two strategies: (i) at pre-defined growth stages, from the first half of heading to the end of flowering (experiment 1, in 2013 to 2015), or (ii) based on timing of infection by F. graminearum, specifically at 10, 7, 4, or 1 day before, or 3 or 5 days after artificial inoculation of the fungus (experiment 2, in 2017 and 2018). Fungicide efficacy was evaluated in terms of FHB incidence, FHB severity, and DON contamination by using generalised mixed models. In experiment 1, all fungicide groups reduced FHB severity and DON but only by <50% compared to an untreated control, with no differences among fungicides or growth stages at time of application. In experiment 2, the efficacy of fungicides was higher for applications at 1 or 4 days before inoculation than at 7 or 10 days before or 3 or 5 days after inoculation, with differences among fungicide groups. Based on our results, the timing of fungicide application for FHB control should be based on the time of F. graminearum infection rather than on wheat phenology. Full article
(This article belongs to the Special Issue Strategies for the Control of Fusarium Head Blight in Cereals)
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11 pages, 1198 KiB  
Article
Optimization of the Microwave-Assisted Extraction of Simple Phenolic Compounds from Grape Skins and Seeds
by Latifa Azaroual, Ali Liazid, Fouad El Mansouri, Jamal Brigui, Ana Ruíz-Rodriguez, Gerardo F. Barbero and Miguel Palma
Agronomy 2021, 11(8), 1527; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081527 - 30 Jul 2021
Cited by 16 | Viewed by 2292
Abstract
A method for the extraction of phenolic compounds from grape seeds and skins using microwave-assisted extraction (MAE) was developed. Optimization of the effects of the extraction parameters in terms of the results of extraction was obtained using the response surface methodology. The parameters [...] Read more.
A method for the extraction of phenolic compounds from grape seeds and skins using microwave-assisted extraction (MAE) was developed. Optimization of the effects of the extraction parameters in terms of the results of extraction was obtained using the response surface methodology. The parameters studied were extraction solvent (methanol, ethanol, acetone, and water), percentage of methanol in water, quantity of sample in relation to volume of extraction solvent (solid:liquid, 10–50 mg mL−1), power (100–500 W), magnetic stirring speed (0–100%), and extraction time (5–20 min). Finally, the repeatability and the intermediate precision of the method were determined. The best conditions proved to be: 65% methanol in water as an optimum extraction solvent; 0.5 g of grape skin or seed in a volume of 25 mL; a power of 500 W with the maximum stirring speed (100%); and an extraction time of 5 min. The phenolic compounds proved to be stable in the optimized extraction conditions. The resulting repeatability and the intermediate precision of the optimized method showed a relative standard deviation below 7%. The new method applied on Napoleon grape allowed for the determination of catechin (453.2 (mg kg−1)), epicatechin (306.3 mg kg−1), caftaric acid (22.37 mg caffeic acid equivalents kg−1), dihydrokaempferol-glycoside (11.13 mg kaempferol equivalents kg−1), quercetin (18.28 mg kg−1), quercetin-3-glucoside (20.09 mg quercetin equivalents kg−1), and kaempferol-3-glucoside (11.10 mg kaempferol equivalents kg−1). Full article
(This article belongs to the Special Issue Extraction and Analysis of Bioactive Compounds in Crops)
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21 pages, 1022 KiB  
Article
Impact of Organic Amendment with Alternate Wetting and Drying Irrigation on Rice Yield, Water Use Efficiency and Physicochemical Properties of Soil
by Ahmad Numery Ashfaqul Haque, Md Kamal Uddin, Muhammad Firdaus Sulaiman, Adibah Mohd Amin, Mahmud Hossain, Azharuddin Abd Aziz and Mehnaz Mosharrof
Agronomy 2021, 11(8), 1529; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081529 - 30 Jul 2021
Cited by 22 | Viewed by 4570
Abstract
A pot experiment was executed to investigate the impact of biochar and compost with water-saving irrigation on the rice yield, water use efficiency, and physicochemical properties of soil. Two irrigation regimes—namely alternate wetting and drying (AWD) and continuous flooding (CF)—and four types of [...] Read more.
A pot experiment was executed to investigate the impact of biochar and compost with water-saving irrigation on the rice yield, water use efficiency, and physicochemical properties of soil. Two irrigation regimes—namely alternate wetting and drying (AWD) and continuous flooding (CF)—and four types of organic amendments (OA)—namely rice husk biochar (RHB), oil palm empty fruit bunch biochar (EFBB), compost and a control—were applied to evaluate their effects. Under the AWD irrigation regime, the maximum grain was produced by RHB (241.12 g), whereas under the same organic amendments, both AWD and CF produced a similar grain yield. Under the same organic amendment, a significantly higher water use efficiency (WUE) was observed from the AWD irrigation with RHB (6.30 g L−1) and EFBB (5.80 g L−1). Within the same irrigation regime, soil pH, cation exchange capacity, total carbon, total nitrogen and available phosphorus were enhanced due to the incorporation of biochar and compost, while higher soil exchangeable potassium was observed under CF irrigation for all treatments. RHB and EFBB significantly reduced the soil bulk density (up to 20.70%) and increased porosity (up to 16.70%) under both irrigation regimes. The results imply that the use of biochar with AWD irrigation could enhance the nutrient uptake and physicochemical properties of soil and allow rice to produce a greater yield with less water consumption. Full article
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17 pages, 27321 KiB  
Article
Sensor-Based Intrarow Mechanical Weed Control in Sugar Beets with Motorized Finger Weeders
by Jannis Machleb, Gerassimos G. Peteinatos, Markus Sökefeld and Roland Gerhards
Agronomy 2021, 11(8), 1517; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081517 - 29 Jul 2021
Cited by 24 | Viewed by 3258
Abstract
The need for herbicide usage reduction and the increased interest in mechanical weed control has prompted greater attention to the development of agricultural robots for autonomous weeding in the past years. This also requires the development of suitable mechanical weeding tools. Therefore, we [...] Read more.
The need for herbicide usage reduction and the increased interest in mechanical weed control has prompted greater attention to the development of agricultural robots for autonomous weeding in the past years. This also requires the development of suitable mechanical weeding tools. Therefore, we devised a new weeding tool for agricultural robots to perform intrarow mechanical weed control in sugar beets. A conventional finger weeder was modified and equipped with an electric motor. This allowed the rotational movement of the finger weeders independent of the forward travel speed of the tool carrier. The new tool was tested in combination with a bi-spectral camera in a two-year field trial. The camera was used to identify crop plants in the intrarow area. A controller regulated the speed of the motorized finger weeders, realizing two different setups. At the location of a sugar beet plant, the rotational speed was equal to the driving speed of the tractor. Between two sugar beet plants, the rotational speed was either increased by 40% or decreased by 40%. The intrarow weed control efficacy of this new system ranged from 87 to 91% in 2017 and from 91 to 94% in 2018. The sugar beet yields were not adversely affected by the mechanical treatments compared to the conventional herbicide application. The motorized finger weeders present an effective system for selective intrarow mechanical weeding. Certainly, mechanical weeding involves the risk of high weed infestations if the treatments are not applied properly and in a timely manner regardless of whether sensor technology is used or not. However, due to the increasing herbicide resistances and the continuing bans on herbicides, mechanical weeding strategies must be investigated further. The mechanical weeding system of the present study can contribute to the reduction of herbicide use in sugar beets and other wide row crops. Full article
(This article belongs to the Special Issue Application of Sensors for Mechanical Weed Control)
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17 pages, 5042 KiB  
Article
Lychee Surface Defect Detection Based on Deep Convolutional Neural Networks with GAN-Based Data Augmentation
by Chenglong Wang and Zhifeng Xiao
Agronomy 2021, 11(8), 1500; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081500 - 28 Jul 2021
Cited by 35 | Viewed by 4032
Abstract
The performance of fruit surface defect detection is easily affected by factors such as noisy background and foliage occlusion. In this study, we choose lychee as a fruit type to investigate its surface quality. Lychees are hard to preserve and have to be [...] Read more.
The performance of fruit surface defect detection is easily affected by factors such as noisy background and foliage occlusion. In this study, we choose lychee as a fruit type to investigate its surface quality. Lychees are hard to preserve and have to be stored at low temperatures to keep fresh. Additionally, the surface of lychees is subject to scratches and cracks during harvesting/processing. To explore the feasibility of the automation of defective surface detection for lychees, we build a dataset with 3743 samples divided into three categories, namely, mature, defects, and rot. The original dataset suffers an imbalanced distribution issue. To address it, we adopt a transformer-based generative adversarial network (GAN) as a means of data augmentation that can effectively enhance the original training set with more and diverse samples to rebalance the three categories. In addition, we investigate three deep convolutional neural network (DCNN) models, including SSD-MobileNet V2, Faster RCNN-ResNet50, and Faster RCNN-Inception-ResNet V2, trained under different settings for an extensive comparison study. The results show that all three models demonstrate consistent performance gains in mean average precision (mAP), with the application of GAN-based augmentation. The rebalanced dataset also reduces the inter-category discrepancy, allowing a DCNN model to be trained equally across categories. In addition, the qualitative results show that models trained under the augmented setting can better identify the critical regions and the object boundary, leading to gains in mAP. Lastly, we conclude that the most cost-effective model, SSD-MobileNet V2, presents a comparable mAP (91.81%) and a superior inference speed (102 FPS), suitable for real-time detection in industrial-level applications. Full article
(This article belongs to the Special Issue Applications of Deep Learning in Smart Agriculture)
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18 pages, 6545 KiB  
Article
Modeling of Durum Wheat Yield Based on Sentinel-2 Imagery
by Chris Cavalaris, Sofia Megoudi, Maria Maxouri, Konstantinos Anatolitis, Marios Sifakis, Efi Levizou and Aris Kyparissis
Agronomy 2021, 11(8), 1486; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081486 - 27 Jul 2021
Cited by 20 | Viewed by 2464
Abstract
In this study, a modelling approach for the estimation/prediction of wheat yield based on Sentinel-2 data is presented. Model development was accomplished through a two-step process: firstly, the capacity of Sentinel-2 vegetation indices (VIs) to follow plant ecophysiological parameters was established through measurements [...] Read more.
In this study, a modelling approach for the estimation/prediction of wheat yield based on Sentinel-2 data is presented. Model development was accomplished through a two-step process: firstly, the capacity of Sentinel-2 vegetation indices (VIs) to follow plant ecophysiological parameters was established through measurements in a pilot field and secondly, the results of the first step were extended/evaluated in 31 fields, during two growing periods, to increase the applicability range and robustness of the models. Modelling results were examined against yield data collected by a combine harvester equipped with a yield-monitoring system. Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) were examined as plant signals and combined with Normalized Difference Water Index (NDWI) and/or Normalized Multiband Drought Index (NMDI) during the growth period or before sowing, as water and soil signals, respectively. The best performing model involved the EVI integral for the 20 April–31 May period as a plant signal and NMDI on 29 April and before sowing as water and soil signals, respectively (R2 = 0.629, RMSE = 538). However, model versions with a single date and maximum seasonal VIs values as a plant signal, performed almost equally well. Since the maximum seasonal VIs values occurred during the last ten days of April, these model versions are suitable for yield prediction. Full article
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15 pages, 939 KiB  
Article
Nutrient Solution Deprivation as a Tool to Improve Hydroponics Sustainability: Yield, Physiological, and Qualitative Response of Lettuce
by Michele Ciriello, Luigi Formisano, Antonio Pannico, Christophe El-Nakhel, Giancarlo Fascella, Luigi Giuseppe Duri, Francesco Cristofano, Beniamino Riccardo Gentile, Maria Giordano, Youssef Rouphael, Giovanna Marta Fusco, Pasqualina Woodrow and Petronia Carillo
Agronomy 2021, 11(8), 1469; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081469 - 23 Jul 2021
Cited by 17 | Viewed by 5145
Abstract
Hydroponics growing systems often contain excessive nutrients (especially nitrates), which could lead to a quality loss in ready-to-eat leafy vegetables and posing a health risk to consumers, if managed inadequately. A floating raft system was adopted to assay the production and quality performance [...] Read more.
Hydroponics growing systems often contain excessive nutrients (especially nitrates), which could lead to a quality loss in ready-to-eat leafy vegetables and posing a health risk to consumers, if managed inadequately. A floating raft system was adopted to assay the production and quality performance of lettuce (Lactuca sativa L. cv ‘Maravilla De Verano Canasta’) deprived of the nutrient solution by replacement with only water, three and six days before harvest. Yield and quality parameters, mineral composition, pigments, organic acids, amino acids profile, soluble proteins, and carbohydrate content were determined. Nutrient solution deprivation six days before harvest resulted in a significant reduction in leaf nitrate (−53.3%) concomitant with 13.8% of yield loss, while plants deprived of nutrient solution three days before harvest increased total phenols content (32.5%) and total ascorbic acid (102.1%), antioxidant activity (82.7%), anthocyanins (7.9%), sucrose (38.9%), starch (19.5%), and γ-aminobutyric acid (GABA; 28.2%), with a yield reduction of 4.7%, compared to the control. Our results suggest that nutrient solution deprivation three days before harvest is a successful strategy to reduce nitrate content and increase the nutritional quality of lettuce grown in floating raft systems with negligible impact on yield. These promising results warrant further investigation of the potential effect of nutrient solution deprivation on the quality attributes of other leafy vegetables cultivated in floating raft systems and in a “cascade” growing system. Full article
(This article belongs to the Collection Nutrition Management of Hydroponic Vegetable Crops)
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20 pages, 1334 KiB  
Article
Insecticidal Effect of Zinc Oxide and Titanium Dioxide Nanoparticles against Bactericera cockerelli Sulc. (Hemiptera: Triozidae) on Tomato Solanum lycopersicum
by José A. Gutiérrez-Ramírez, Rebeca Betancourt-Galindo, Luis A. Aguirre-Uribe, Ernesto Cerna-Chávez, Alberto Sandoval-Rangel, Epifanio Castro-del Ángel, Julio C. Chacón-Hernández, Josué I. García-López and Agustín Hernández-Juárez
Agronomy 2021, 11(8), 1460; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081460 - 22 Jul 2021
Cited by 30 | Viewed by 4399
Abstract
The use of nanoparticles (NPs) has generated an alternative pest control. The objective was to evaluate the insecticidal effect of zinc oxide nanoparticles (ZnO NPs), titanium dioxide nanoparticles (TiO2 NPs), and their combination on Bactericera cockerelli (Hemiptera: Triozidae) second-stage nymphs under [...] Read more.
The use of nanoparticles (NPs) has generated an alternative pest control. The objective was to evaluate the insecticidal effect of zinc oxide nanoparticles (ZnO NPs), titanium dioxide nanoparticles (TiO2 NPs), and their combination on Bactericera cockerelli (Hemiptera: Triozidae) second-stage nymphs under laboratory and greenhouse conditions in tomato. The laboratory research was carried out with the leaf immersion bioassay method under a complete randomized design, and in the greenhouse by direct plant spraying under a randomized block design; in both designs, a control without NPs was added. Mortality was recorded every 24 h for 4 days. Both NPs in the laboratory and greenhouse showed toxicity to B. cockerelli nymphs. Results in the laboratory showed that NPs significantly caused increased mortality of 88, 99, and 100% 96 h after treatment of ZnO NPs, TiO2 NPs, and their combinations, at 1000, 100, and 250 ppm, respectively. Direct spray of plants in the greenhouse showed low mortality with 27, 32, and 23% after 96 h of ZnO NPs, TiO2 NPs, and their combinations, at 3000, 500, and 250 ppm, respectively. These results on B. cockerelli control seem promising. Nanoparticles as insecticides are a novel strategy, however, further investigation is required in field tests to obtain suitable efficacy for use in a pest management system. Full article
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24 pages, 12016 KiB  
Article
Deep-Learning-Based Automated Palm Tree Counting and Geolocation in Large Farms from Aerial Geotagged Images
by Adel Ammar, Anis Koubaa and Bilel Benjdira
Agronomy 2021, 11(8), 1458; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081458 - 22 Jul 2021
Cited by 34 | Viewed by 5927
Abstract
In this paper, we propose an original deep learning framework for the automated counting and geolocation of palm trees from aerial images using convolutional neural networks. For this purpose, we collected aerial images from two different regions in Saudi Arabia, using two DJI [...] Read more.
In this paper, we propose an original deep learning framework for the automated counting and geolocation of palm trees from aerial images using convolutional neural networks. For this purpose, we collected aerial images from two different regions in Saudi Arabia, using two DJI drones, and we built a dataset of around 11,000 instances of palm trees. Then, we applied several recent convolutional neural network models (Faster R-CNN, YOLOv3, YOLOv4, and EfficientDet) to detect palms and other trees, and we conducted a complete comparative evaluation in terms of average precision and inference speed. YOLOv4 and EfficientDet-D5 yielded the best trade-off between accuracy and speed (up to 99% mean average precision and 7.4 FPS). Furthermore, using the geotagged metadata of aerial images, we used photogrammetry concepts and distance corrections to automatically detect the geographical location of detected palm trees. This geolocation technique was tested on two different types of drones (DJI Mavic Pro and Phantom 4 pro) and was assessed to provide an average geolocation accuracy that attains 1.6 m. This GPS tagging allows us to uniquely identify palm trees and count their number from a series of drone images, while correctly dealing with the issue of image overlapping. Moreover, this innovative combination between deep learning object detection and geolocalization can be generalized to any other objects in UAV images. Full article
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27 pages, 11149 KiB  
Article
Combining Ability and Gene Action Controlling Grain Yield and Its Related Traits in Bread Wheat under Heat Stress and Normal Conditions
by Mohamed M. Kamara, Khaled M. Ibrahim, Elsayed Mansour, Ahmed M. S. Kheir, Mousa O. Germoush, Diaa Abd El-Moneim, Mohamed I. Motawei, Ahmed Y. Alhusays, Mona Ali Farid and Medhat Rehan
Agronomy 2021, 11(8), 1450; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11081450 - 21 Jul 2021
Cited by 33 | Viewed by 3711
Abstract
High temperature is a major environmental stress that devastatingly affects wheat production. Thenceforth, developing heat-tolerant and high-yielding wheat genotypes has become more critical to sustaining wheat production particularly under abrupt climate change and fast-growing global population. The present study aimed to evaluate parental [...] Read more.
High temperature is a major environmental stress that devastatingly affects wheat production. Thenceforth, developing heat-tolerant and high-yielding wheat genotypes has become more critical to sustaining wheat production particularly under abrupt climate change and fast-growing global population. The present study aimed to evaluate parental genotypes and their cross combinations under normal and heat stress conditions, exploring their diversity based on dehydration-responsive element-binding 2 gene (DREB, stress tolerance gene in response to abiotic stress) in parental genotypes, and determining gene action controlling yield traits through half-diallel analysis. Six diverse bread wheat genotypes (local and exotic) and their 15 F1 hybrids were evaluated at two different locations under timely and late sowing dates. Sowing date, location, genotype, and their interactions significantly impacted the studied traits; days to heading, chlorophyll content, plant height, grain yield, and its attributes. Cluster analysis classified the parents and their crosses into four groups varying from heat-tolerant to heat-sensitive based on heat tolerance indices. The parental genotypes P2 and P4 were identified as an excellent source of beneficial alleles for earliness and high yielding under heat stress. This was corroborated by DNA sequence analysis of DREB transcription factors. They were the highest homologies for dehydrin gene sequence with heat-tolerant wheat species. The hybrid combinations of P1 × P5, P1 × P6, P2 × P4, and P3 × P5 were detected to be good specific combiners for grain yield and its attributes under heat stress conditions. These designated genotypes could be used in wheat breeding for developing heat-tolerant and climate-resilient cultivars. The non-additive genetic variances were preponderant over additive genetic variances for grain yield and most traits under both sowing dates. The narrow-sense heritability ranged from low to moderate for most traits. Strong positive associations were detected between grain yield and each of chlorophyll content, plant height, number of grains/spike, and thousand-grain weights, which suggest their importance for indirect selection under heat stress, especially in early generations, due to the effortlessness of their measurement. Full article
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21 pages, 15756 KiB  
Article
Rebalance the Nutritional Status and the Productivity of High CaCO3-Stressed Sweet Potato Plants by Foliar Nourishment with Zinc Oxide Nanoparticles and Ascorbic Acid
by Ahmed A. M. Awad, Atef A. A. Sweed, Mostafa M. Rady, Ali Majrashi and Esmat F. Ali
Agronomy 2021, 11(7), 1443; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11071443 - 20 Jul 2021
Cited by 19 | Viewed by 2431
Abstract
The use of nano-fertilizers and antioxidants for specific crops to minimize the negative effect of abiotic stresses is imperative. Two field experiments were fulfilled during two summer seasons (2019 and 2020) to study the response of sweet potato (Beauregard cv.) plants grown in [...] Read more.
The use of nano-fertilizers and antioxidants for specific crops to minimize the negative effect of abiotic stresses is imperative. Two field experiments were fulfilled during two summer seasons (2019 and 2020) to study the response of sweet potato (Beauregard cv.) plants grown in calcareous soil (CaCO3 = 10.8–11.3%) to foliar nourishment with zinc oxide nanoparticles (ZnONPs) and ascorbic acid (ASA) applied individually or in a mixture. Both ZnONPs and ASA were applied in three doses: 0, 1000, or 1500 mg L−1 for ZnONPs, and 0, 250 and 500 mg L−1 for ASA. The highest values of iron (Fe) and manganese (Mn) contents were recorded in both seasons, while those of phosphorus (P) and copper (Cu) were recorded in the 2020 season with ZnONPs applied at 1500 mg L−1. Furthermore, in both seasons, the maximum values of nutrient contents, excluding Mn content, were obtained with ASA applied at 500 mg L−1. However, applying both ZnONPs and ASA in a mixture bypassed each applied alone, with the highest overall nutrient contents being recorded, with few exceptions, with the highest dose of the mixture. The trend of the tuber root nutrient contents was correlated with the corresponding values in the leaves. Maximum tuber root yield was obtained with foliar feeding with 1000 mg ZnONP and 250 mg ASA L−1 in both seasons. The resulting data recommend the use of foliar nourishment with fertilizer nanoparticles and antioxidants to enable stressed plants to collect appropriate nutrient contents from the defective soils. Full article
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16 pages, 3589 KiB  
Article
Assessment of Weed Classification Using Hyperspectral Reflectance and Optimal Multispectral UAV Imagery
by Nik Norasma Che’Ya, Ernest Dunwoody and Madan Gupta
Agronomy 2021, 11(7), 1435; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11071435 - 19 Jul 2021
Cited by 28 | Viewed by 4302
Abstract
Weeds compete with crops and are hard to differentiate and identify due to their similarities in color, shape, and size. In this study, the weed species present in sorghum (sorghum bicolor (L.) Moench) fields, such as amaranth (Amaranthus macrocarpus), pigweed [...] Read more.
Weeds compete with crops and are hard to differentiate and identify due to their similarities in color, shape, and size. In this study, the weed species present in sorghum (sorghum bicolor (L.) Moench) fields, such as amaranth (Amaranthus macrocarpus), pigweed (Portulaca oleracea), mallow weed (Malva sp.), nutgrass (Cyperus rotundus), liver seed grass (Urochoa panicoides), and Bellive (Ipomea plebeian), were discriminated using hyperspectral data and were detected and analyzed using multispectral images. Discriminant analysis (DA) was used to identify the most significant spectral bands in order to discriminate weeds from sorghum using hyperspectral data. The results demonstrated good separation accuracy for Amaranthus macrocarpus, Urochoa panicoides, Malva sp., Cyperus rotundus, and Sorghum bicolor (L.) Moench at 440, 560, 680, 710, 720, and 850 nm. Later, the multispectral images of these six bands were collected to detect weeds in the sorghum crop fields using object-based image analysis (OBIA). The results showed that the differences between sorghum and weed species were detectable using the six selected bands, with data collected using an unmanned aerial vehicle. Here, the highest spatial resolution had the highest accuracy for weed detection. It was concluded that each weed was successfully discriminated using hyperspectral data and was detectable using multispectral data with higher spatial resolution. Full article
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