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Agronomy, Volume 11, Issue 5 (May 2021) – 207 articles

Cover Story (view full-size image): European regulation promotes the use of formulations based on natural products for Integrated Pest Management. In this work, the physicochemical characteristics of the biomass of two halophytes from the Asturian coast (Spain)—namely, rock samphire and sea carrot—were studied. In view of the phytochemicals present in their hydromethanolic extracts, their valorization as sources of antimicrobial agents for crop protection was explored, finding a remarkable inhibition against Erwinia amylovora, Xylophilus ampelinus and Diplodia seriata phytopathogens in in vitro tests. The conjugate complexes of these wild plants with chitosan oligomers may be put forward as promising antimicrobial treatments, either in organic agriculture or as a substitute for treatments based on chemical synthesis fungicides in conventional management. View this paper.
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Article
Yield Comparisons between Cotton Variety Xin Nong Mian 1 and Its Transgenic ScALDH21 Lines under Different Water Deficiencies in a Desert-Oasis Ecotone
Agronomy 2021, 11(5), 1019; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051019 - 20 May 2021
Viewed by 559
Abstract
Water scarcity is the major limiting factor for oasis-desert agricultural production of cotton. It is necessary to improve cotton for drought tolerance and minimize drought-related crop losses, and the transgenic approach is efficient for cotton improvement. In order to evaluate the value of [...] Read more.
Water scarcity is the major limiting factor for oasis-desert agricultural production of cotton. It is necessary to improve cotton for drought tolerance and minimize drought-related crop losses, and the transgenic approach is efficient for cotton improvement. In order to evaluate the value of ScALDH21 transgenic cotton (G. hirsutum L.), it was tested in the main cotton region of south Xinjiang, in an environment of extreme drought around the desert. Transgenic cotton, overexpressing aldehyde dehydrogenase gene (ScALDH21) from the desiccation-tolerant moss Syntrichia caninervis in cotton variety Xin Nong Mian 1, was field-tested under six treatments based on three irrigation schedules and two irrigation levels (full (FI) and deficit (DI) irrigation) as follows: root zone model-simulated forecast irrigation (F) (FFI and FDI), soil moisture sensor-based irrigation (S) (SFI and SDI), and flood irrigation based on experience estimates (E) (EFI and EDI) to evaluate growth and yield performances. The results revealed that plant height and leaf area increased significantly in ScALDH21-transgenic cotton genotypes under all treatments. Physiological parameters such as chlorophyll content, net photosynthesis rate, and instantaneous water use efficiency were not significantly highly in transgenic lines compared to non-transgenic plants (NT). However, transgenic lines showed significantly improved yield and superior fiber quality than NT plants regardless of irrigation. The results demonstrate that ScALDH21-transgenic lines were excellent compared to NT plants under different water deficiency conditions. The study also provides guidelines for optimal irrigation protocol and minimum water requirements for the use of the ScALDH21-transgenic cotton lines in arid zones. Full article
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Article
Understanding the Dynamic of Rice Farming Systems in Southern Mozambique to Improve Production and Benefits to Smallholders
Agronomy 2021, 11(5), 1018; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051018 - 20 May 2021
Viewed by 500
Abstract
Rice farming systems (RFSs) in southern Mozambique are very heterogeneous and diversified, which has implications for smallholders’ adoption of each RFS, as well as on rice production and productivity in the region. In this regard, it is important to understand: (i) which RFS [...] Read more.
Rice farming systems (RFSs) in southern Mozambique are very heterogeneous and diversified, which has implications for smallholders’ adoption of each RFS, as well as on rice production and productivity in the region. In this regard, it is important to understand: (i) which RFS typologies can be leveraged to improve rice production and productivity; (ii) the drivers for smallholder farmers’ decisions to adopt an RFS; and (iii) which policies/incentives could enhance existing RFSs. The present study was based on surveys of 341 smallholder rice farmers in the Chókwè Irrigation Scheme (CIS), southern Mozambique. Data on the productivity of rice, size of the herd, and total other crop types were used to frame the RFS typologies. A multinomial logit model (MLM) and multiple linear regression (MLR) were applied to determine the driver for each RFS, and predict the constraints for production and yield. Based on cluster analysis, four typologies of RFSs were identified: the subsistence farming system (FS), specialised rice FS, mixed crops FS, and rice–livestock FS. Farms with longer experience reported applying more fertiliser and seedlings per unit hectare. The availability of labour increased the likelihood of adopting the mixed crops FS and rice–livestock FS. Older households were more likely to adopt the subsistence FS, and live closer to the farming fields. Yield of rice was positively associated with inputs such as fertilisers, pesticides, and seedlings, as well as years of experience of the household. Our results suggest that smallholder farmers need more assistance and technical support to identify and adopt more productive and less costly RFSs in this region. Full article
(This article belongs to the Special Issue Cropping Systems and Agronomic Management Practices of Field Crops)
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Article
Effects of Manure and Chemical Fertilizer on Bacterial Community Structure and Soil Enzyme Activities in North China
Agronomy 2021, 11(5), 1017; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051017 - 20 May 2021
Viewed by 480
Abstract
The application of organic fertilizer affects soil microbes and enzyme activities. In this study, we explored the effects of various long-term different fertilization treatments (manure, M; chemical fertilizer, NP; manure + chemical fertilizer, MNP; and no fertilizer, CK) on bacterial community structure and [...] Read more.
The application of organic fertilizer affects soil microbes and enzyme activities. In this study, we explored the effects of various long-term different fertilization treatments (manure, M; chemical fertilizer, NP; manure + chemical fertilizer, MNP; and no fertilizer, CK) on bacterial community structure and soil sucrase, urease, and alkaline phosphatase activities in Shaping, Hequ, China. High-throughput sequencing was used to amplify the third to the fourth hypervariable region of the 16S ribosomal RNA for analysis of the bacterial community structure. Enzyme activities were determined by colorimetry. Soil treated with MNP had the highest bacterial Abundance-based Coverage Estimator index and enzyme activities. The principal coordinates analysis results showed significant differences among the various fertilization treatments (p < 0.001). Proteobacteria, Actinobacteria, Acidobacteria, Gemmatimonadetes, and Chloroflexi were consistently dominant in all soil samples. The redundancy analysis and Monte Carlo permutation tests showed that the soil bacterial communities were significantly correlated with alkali-hydrolyzable nitrogen, organic matter, urease, and alkaline phosphatase. Our results reveal the fundamentally different effects that organic and inorganic fertilizers have on soil bacterial communities and their functions. Full article
(This article belongs to the Special Issue Soil Microbes and Nutrient Recycling in Agroecosystems)
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Article
Sulfonamides in Tomato from Commercial Greenhouses Irrigated with Reclaimed Wastewater: Uptake, Translocation and Food Safety
Agronomy 2021, 11(5), 1016; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051016 - 20 May 2021
Viewed by 454
Abstract
The presence of antibiotics in crops is mainly caused by their irrigation with reclaimed wastewater and by the use of organic amendments of animal origin. During this work, the fate of sulfonamide antibiotics in tomato crop has been assessed in two commercial greenhouses [...] Read more.
The presence of antibiotics in crops is mainly caused by their irrigation with reclaimed wastewater and by the use of organic amendments of animal origin. During this work, the fate of sulfonamide antibiotics in tomato crop has been assessed in two commercial greenhouses located in Almería (Spain) irrigated with reclaimed wastewater. Samplings were made annually for two years. Sulfonamides in several parts of the plant (roots, leaves and fruits) as well as reclaimed wastewater, amendments and soils were analyzed by UHPLC-MS/MS. The results showed that sulfonamides accumulated in soils (sulfamethoxazole between 2 and 14 µg kg−1; sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine and sulfadimethoxine in concentrations below 1 µg kg−1) were in the reclaimed wastewater at concentrations in the ng L−1 range. Their distribution in plants depended on the sulfonamide. The sulfonamides detected in tomato were sulfadiazine, sulfapyridine, sulfamethazole, sulfamethoxazole and sulfadimethoxine. Sulfamethoxazole was the antibiotic with highest concentration in tomato fruit, exceeding 30 µg kg−1. All sulfonamides were below the Acceptable Daily Intake, however, further studies and legislation are needed to assure food safety. Full article
(This article belongs to the Special Issue Air and Soil Pollution Effects on Agroecosystems)
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Review
Agronomic Biofortification of Significant Cereal Crops with Selenium—A Review
Agronomy 2021, 11(5), 1015; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051015 - 20 May 2021
Cited by 1 | Viewed by 616
Abstract
Selenium (Se) is an important micronutrient which is essential for most living organisms and occurs in both organic and inorganic forms in the water system, soils, biomass, and the atmosphere. In addition to being essential for humans and animals, Se is beneficial for [...] Read more.
Selenium (Se) is an important micronutrient which is essential for most living organisms and occurs in both organic and inorganic forms in the water system, soils, biomass, and the atmosphere. In addition to being essential for humans and animals, Se is beneficial for plants and is mostly involved in antioxidant activity/response, as well as a growth promoter. Se deficiency in the diet is a global problem, and Se levels in soils generally reflect its presence in food and, thus, availability to humans. Se participates in the antioxidant response mechanisms of the organism, heavy-metal detoxification, and regulation of the reproductive and immune system, as well as ensures the proper function of the thyroid gland. Plants are the main dietary source of Se for humans. Biofortification is a key strategy to increase Se in edible parts of plants. Agronomic biofortification provides an effective route to increase Se content in edible crop products via application of Se-enriched fertilizers to soil or by foliar application. The most common cereals in the human diet are wheat, rice, maize, and barley, making them the most suitable targets for agronomic biofortification. This review focuses on summarizing the most efficient form and method of Se application via agronomic biofortification corroborated by a meta-analysis of the literature reports. In the assessed literature, foliar application showed better results compared to application in soil. The selenate form appears to be the more efficient form of Se for biofortification than selenite in the most common cereals in human diet: wheat, rice, maize, and barley. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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Review
Nocturnal Bees as Crop Pollinators
Agronomy 2021, 11(5), 1014; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051014 - 20 May 2021
Cited by 1 | Viewed by 670
Abstract
Bees are typically diurnal but around 1% of described species have nocturnal activity. Nocturnal bees are still poorly studied due to bias towards studying diurnal insects. However, knowledge concerning their biology and role as crop pollinators has increased. We review the literature on [...] Read more.
Bees are typically diurnal but around 1% of described species have nocturnal activity. Nocturnal bees are still poorly studied due to bias towards studying diurnal insects. However, knowledge concerning their biology and role as crop pollinators has increased. We review the literature on nocturnal bees’ traits and their host plants, and assess the crop pollination effectiveness of this neglected group. Nocturnal bees have visual adaptations to cope with low light intensities, and floral scents are a key sensory cue used to find their host flowers. Nocturnal bees generally show high flower constancy, the ability to vibrate flowers, and high transfer rates of pollen grains to stigmas. The flowers visited by nocturnal bees range from small radial and zygomorphic flowers to large brush blossoms; moreover, they visit plants with different flowering strategies. Nocturnal bees are effective pollinators of regional fruit crops in Brazil, such as cambuci (Campomanesia phaea), guaraná (Paullinia cupana), cajá (Spondias mombin), and in North America of cultivated pumpkins (Cucurbita species). However, they most likely are pollinators of several other crops. Strategies to host high numbers of nocturnal bees around cropping areas should be taken, such as preserving adjacent native forests, restricting soil management, providing food resources beyond crop flowers, and avoiding light pollution. Full article
(This article belongs to the Special Issue Pollinator Diversity and Pollination in Agricultural Systems)
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Article
VNT4, a Derived Formulation of Glutacetine® Biostimulant, Improved Yield and N-Related Traits of Bread Wheat When Mixed with Urea-Ammonium-Nitrate Solution
Agronomy 2021, 11(5), 1013; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051013 - 20 May 2021
Viewed by 471
Abstract
Optimizing nitrogen use efficiency (NUE) could mitigate the adverse effects of nitrogen (N) fertilizers by limiting their environmental risks and raising agronomic performance. We studied the effects of VNT4, a derived formulation of Glutacetine® biostimulant, mixed with urea-ammonium-nitrate solution (UAN) on the [...] Read more.
Optimizing nitrogen use efficiency (NUE) could mitigate the adverse effects of nitrogen (N) fertilizers by limiting their environmental risks and raising agronomic performance. We studied the effects of VNT4, a derived formulation of Glutacetine® biostimulant, mixed with urea-ammonium-nitrate solution (UAN) on the growth, N-related traits and agronomic performance of winter wheat (Triticum aestivum L.). The experiment was performed under six contrasting field conditions over two years in Normandy (France), including a site where 15N labelling was undertaken. Taking into account all the sites, we report that VNT4 significantly improved grain yield (+359 kg ha−1), total grain N and NUE. VNT4 application improved growth during tillering and stem elongation (+10.7%), and N and 15N uptake between tillering and maturity (+7.3% N and +16.9% 15N) leading to a higher N accumulation at maturity (+9.3% N). This N mainly originated from fertilizer (+19.4% 15N) and was assimilated after the flag leaf stage in particular (+47.6% 15N). These effects could be related to maintenance of physiological functions of flag leaves as suggested by the enhancement of their nutrient status (especially S, Zn and Mo). The adoption of VNT4 as a UAN additive is an efficient agronomic practice to enhance wheat productivity under an oceanic temperate climate. Full article
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Article
Effect of Soil Water Availability on Physiological Parameters, Yield, and Seed Quality in Four Quinoa Genotypes (Chenopodium quinoa Willd.)
Agronomy 2021, 11(5), 1012; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051012 - 20 May 2021
Viewed by 546
Abstract
Drought represents significant environmental stress, and improving agriculture water management and yield is a priority goal. The effect of diminishing soil water content in the grain filling (GF) stage, throughout physiological maturity (GM), on the yield and grain quality, leaf water potential (LWP), [...] Read more.
Drought represents significant environmental stress, and improving agriculture water management and yield is a priority goal. The effect of diminishing soil water content in the grain filling (GF) stage, throughout physiological maturity (GM), on the yield and grain quality, leaf water potential (LWP), and maximum quantum yield (Fv/Fm) in four long photoperiod quinoa genotypes was evaluated in the South-Central zone of Chile, during the 2014–2015 and 2015–2016 seasons. Five irrigation treatments (T) were established. Irrigation was carried out when the available water (AW) of the root zone reached values of 100%, 70%, 40%, 20%, and 0%. The lowest LWP values were obtained by T20 and T0 (−1.95 MPa). The ‘Morado’ genotype reached the lowest LWP at both seasons, while the highest average LWP was achieved by the ‘AG 2010’ (2014–2015) and ‘Cahuil’ genotypes (2015–2016). A global trend of Fv/Fm values was observed from GF to GM: 0.74 toward 0.79 (2014/2015), and 0.74 toward 0.82 (2015/2016). Only during the second season, Fv/Fm showed differences among irrigation treatments. Total average grain yields in the second season (2.97 t ha−1) were greater than those in the first season (1.43 t ha−1). In both seasons, the ‘Cahuil’ genotype and T100 reached the highest yields. A significative decrease in yield was observed when AW diminished. A direct relationship between seed yield and leaf water potential (ΔY/ΔLWP) was found in all genotypes, varying between 5.53 (‘Cahuil’) and 2.86 t ha−1 MPa−1 (‘AG 2010’). Total proteins, albumins, and globulins varied between seasons, with almost no differences among irrigation treatments. Only the ‘Morado’ genotype showed a slight trend to obtain a higher content of total protein in both seasons. It is possible to grow quinoa under irrigation deficit conditions between GF throughout GM, maintaining yield parameters and nutritional quality. Full article
(This article belongs to the Section Water Use and Irrigation)
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Article
Determination of the Elemental Composition of Aromatic Plants Cultivated Industrially in the Republic of Moldova Using Neutron Activation Analysis
Agronomy 2021, 11(5), 1011; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051011 - 20 May 2021
Viewed by 374
Abstract
The mineral contents of roots, leaves, stalks, and inflorescences of the aromatic plant species Anethum graveolens L., Coriandrum sativum L., Lavandula angustifolia Mill., Levisticum officinale W.D.J. Koch, and Salvia sclarea L. were studied by means of neutron activation analysis. The contents of 36 [...] Read more.
The mineral contents of roots, leaves, stalks, and inflorescences of the aromatic plant species Anethum graveolens L., Coriandrum sativum L., Lavandula angustifolia Mill., Levisticum officinale W.D.J. Koch, and Salvia sclarea L. were studied by means of neutron activation analysis. The contents of 36 major and trace elements were determined and biological transfer coefficients were calculated. Among major and minor elements, K with a content in the range of 9230–59,600 mg/kg and Fe in the range of 69–3420 mg/kg were the most abundant elements in the studied plants. The content of the toxicant As ranged between 0.14–0.79 mg/kg; however, in the leaves (1.3 mg/kg) and inflorescences (1.0 mg/kg) of L. angustifolia there was found to be about 1 mg/kg, equal to the guideline maximal level recommended for food by the WHO. By comparing the data to Markert’s Reference Plant, “chemical fingerprints” were identified for each species. High contents of the elements Al, Hf, Se, Sc, Na, Ta, Th were determined in all studied plants. Collocated soil samples from the cultivation field were analyzed to calculate the biological accumulation coefficients for 35 of the elements determined in the plants. Considering the levels of chemical elements, the medicinal herb samples investigated are considered as relatively safe for human consumption. Full article
(This article belongs to the Special Issue Air and Soil Pollution Effects on Agroecosystems)
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Article
Intercropping in Rice Farming under the System of Rice Intensification—An Agroecological Strategy for Weed Control, Better Yield, Increased Returns, and Social–Ecological Sustainability
Agronomy 2021, 11(5), 1010; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051010 - 20 May 2021
Viewed by 671
Abstract
Rice is the staple food for more than half of the world’s population. In South Asia, rice farming systems provide food to the majority of the population, and agriculture is a primary source of livelihood. With the demand for nutritious food increasing, introducing [...] Read more.
Rice is the staple food for more than half of the world’s population. In South Asia, rice farming systems provide food to the majority of the population, and agriculture is a primary source of livelihood. With the demand for nutritious food increasing, introducing innovative strategies in farming systems is imperative. In this regard, intensification of rice farming is intricately linked with the challenges of water scarcity, soil degradation, and the vagaries of climate change. Agroecological farming systems like the System of Rice Intensification (SRI) have been proposed as water-saving and sustainable ways of food production. This study examines the effect of intercropping beans with rice under SRI management on the growth of weeds and on the different plant growth parameters. Intercropping led to a 65% decrease in weed infestation on average, which is important given that weed infestation is stated as a criticism of SRI in some circles and is a major factor in limiting yield in rice-producing regions. In addition to the water savings of about 40% due to the SRI methodology, the innovation led to an increase in rice yield by 33% and an increase in the net income of farmers by 57% compared to the conventional rice farming method. The results indicate that intercropping can be a positive addition to the rice farming system, hence contributing to social–ecological sustainability. Full article
(This article belongs to the Special Issue Social-Ecologically More Sustainable Agricultural Production)
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Article
Polyvinylpyrrolidone (PVP) and Na-Alginate Addition Enhances the Survival and Agronomic Performances of a Liquid Inoculant of Bradyrhizobium japonicum for Soybean (Glycine max (L.) Merr.)
Agronomy 2021, 11(5), 1009; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051009 - 20 May 2021
Viewed by 757
Abstract
Nontoxic polymers PVP and Na-alginate may provide a favorable environment for the survival of bacteria. Therefore, PVP and Na-alginate were added to a growth medium to develop a liquid inoculant of Bradyrhizobium japonicum strain. The strain was identified by 16S rDNA sequencing. The [...] Read more.
Nontoxic polymers PVP and Na-alginate may provide a favorable environment for the survival of bacteria. Therefore, PVP and Na-alginate were added to a growth medium to develop a liquid inoculant of Bradyrhizobium japonicum strain. The strain was identified by 16S rDNA sequencing. The addition of PVP (1.8%) and Na-alginate (0.2%) in the medium promoted a better survival (1.93 × 109 cells mL−1) of B. japonicum strain compared to the control (3.50 × 102 cells mL−1) after 6 months of storage. The combination of PVP and Na-alginate ensured 1.53 × 107 cells mL−1 up to 12 months of storage under ambient temperature (28 ± 2 °C), whereas PVP (1.8%) or Na-alginate (0.2%) alone produced similar cell counts only up to 8 months and 6 months, respectively. Consecutive field experiments proved the efficacy of the liquid inoculant on nodulation and yield of soybean. The combination of PVP and Na-alginate-based inoculation of B. japonicum strain significantly increased the nodule number per plant, number of pods per plant, number of seeds per pod, seed yield, and yield per hectare (p ≤ 0.05). Thus, the combination of PVP- and Na-alginate-based inoculation of B. japonicum has great potential to popularize the organic cultivation of soybean. Full article
(This article belongs to the Special Issue Recent Advances in Biological Nitrogen Fixation)
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Article
Morphophysiological, Enzymatic, and Elemental Activity in Greenhouse Tomato Saladette Seedlings from the Effect of Plant Growth-Promoting Rhizobacteria
Agronomy 2021, 11(5), 1008; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051008 - 20 May 2021
Viewed by 559
Abstract
The tomato is a widely cultivated and consumed vegetable globally. Comarca Lagunera is an important tomato-exporting region of Mexico. Salinity is an abiotic factor that reduces productivity and increases production costs. To advance growing period, there is high demand for the sustainable production [...] Read more.
The tomato is a widely cultivated and consumed vegetable globally. Comarca Lagunera is an important tomato-exporting region of Mexico. Salinity is an abiotic factor that reduces productivity and increases production costs. To advance growing period, there is high demand for the sustainable production of seedlings. Plant-growth-promoting rhizobacteria (PGPR) are characterized by improving plant growth through different mechanisms and can be an option for reducing the misuse of chemical fertilizers. The importance of the application of strains, evaluating various inoculation methods (in seed, soil, foliar spraying, and root immersion), should be evaluated to propose biofertilization packages in a specific crop. Thus, the study aimed to determine the effect of PGPR (Bacillus paralicheniformis, Acinetobacter guillouiae, Aeromonas caviae, and Pseudomonas lini) vs. nutrient solution and distilled water in the seedlings stage of saladette-type tomato on morphophysiological variables, nitrate reductase (NR) enzyme activity, and plant minerals via tissue analysis under greenhouse conditions. The four PGPR were inoculated by different methods (inoculation in seed, sprinkling, and both) in saladette-type tomato seedlings under greenhouse conditions and evaluated in vivo 40 days after sowing for morphophysiological variables, such as seedling height; stem diameter; root displaced volume; fresh and dry weight matter of the leaves, stems, and roots; leaf area; and nitrate reductase enzyme activity. The effect of the inoculation of PGPR showed significant results for Pseudomonas lini vs. the control, with 40% higher values, on average, for plant height, stem diameter, displaced root volume, and fresh weight of root, leaf, and stem. The response of enzymatic and mineral content in seedlings was variable with nutrient solution and significant with distilled water. Studies related to the promotion of plants in the subsequent phenological stages of a tomato, considering the selected PGPR, should be considered in future research. Full article
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Article
Transcriptomic and Metabolomic Studies Reveal Mechanisms of Effects of CPPU-Mediated Fruit-Setting on Attenuating Volatile Attributes of Melon Fruit
Agronomy 2021, 11(5), 1007; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051007 - 19 May 2021
Viewed by 478
Abstract
N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU), a synthetic cytokinin-active compound, is widely applied to induce parthenocarpic fruit set and enhance melon fruit enlargement (Cucumis melo L.). CPPU may also influence fruit quality; however, the mechanisms through which this occurs remain unknown. We investigated the differences in [...] Read more.
N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU), a synthetic cytokinin-active compound, is widely applied to induce parthenocarpic fruit set and enhance melon fruit enlargement (Cucumis melo L.). CPPU may also influence fruit quality; however, the mechanisms through which this occurs remain unknown. We investigated the differences in volatile emissions between parthenocarpic fruit set by CPPU (C) and seeded fruit set by artificial pollination (P). Gas chromatography–mass spectrometry (GC–MS) analysis revealed that six volatile organic compounds (VOCs) emitted by the P-group fruits were not detected in C-group fruits. The relative abundances of another 14 VOCs emitted by the CPPU-treated fruits were less than those in the P-group fruits. RNA sequencing analysis indicated that a total of 1027, 994, and 743 differentially expressed genes (DEGs) were detected in the C20 (treatment with 20 mg·L–1 CPPU) vs. P, P-C20 (pollination followed by 20 mg·L−1 CPPU treatment) vs. P, and P-C20 vs. C20 treatments, respectively. Compared with the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, the DEGs related to fatty acid degradation and metabolism, which contribute to volatile production, were enriched. In particular, DEGs such as carotenoid cleavage dioxygenase (CCD)-, lipoxygenase (LOX)-, alcohol dehydrogenase (ADH)-, and alcohol acyltransferase (ATT)-related genes were closely related to the formation of volatiles. In summary, our study provides a metabolic and transcriptomic atlas, reveals the impact of CPPU on VOCs, and enhances our understanding of the mechanisms of CPPU that contribute towards generally reducing the quality of melon fruit. Full article
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Article
Are Copper Nanoparticles Toxic to All Plants? A Case Study on Onion (Allium cepa L.)
Agronomy 2021, 11(5), 1006; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051006 - 19 May 2021
Viewed by 558
Abstract
Sandy soils with high alkalinity are characterized by low copper (Cu) contents that lead to many deficiency symptoms in plants. Cu deficiency in plants can be corrected using several cheap Cu sources. Nevertheless, the effects that novel sources, such as Cu nanoparticles (NPs), [...] Read more.
Sandy soils with high alkalinity are characterized by low copper (Cu) contents that lead to many deficiency symptoms in plants. Cu deficiency in plants can be corrected using several cheap Cu sources. Nevertheless, the effects that novel sources, such as Cu nanoparticles (NPs), have on plants remain poorly studied. In the present work, we investigated the effect and efficiency of Cu supplementation to onion (Allium cepa L.) plants using Cu sulfate, chelate, or NPs, and compared their effects on bulb quality, yield, and contents of phytochemicals. Two successive seasons (2018/2019 and 2019/2020) of field experiments were conducted in newly reclaimed sandy soils, where plants were sprayed with either 10 ppm CuO NPs, 20 ppm CuSO4·5H2O, or 20 ppm of Cu chelates. Overall, Cu deficiency (control) resulted in a significant decrease in yield and all quality traits of onion plants. CuO NPs treatment significantly enhanced growth parameters, including plant height, number of leaves, fresh and dry weight, yield, and bulb quality, compared with Cu sulfate and chelates. This was also the case regarding chemical constituents such as macro- and micro-nutrients, total soluble solids, phytochemical compounds, vitamins, and amino acids. Although Cu sulfate is the cheapest form used for Cu supplementation, results of the present study suggest that CuO NPs was not only safe to use, but also was the treatment that led to the highest onion yield and quality. Full article
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Cycling Phosphorus and Nitrogen through Cropping Systems in an Intensive Dairy Production Region
Agronomy 2021, 11(5), 1005; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051005 - 19 May 2021
Cited by 1 | Viewed by 609
Abstract
As pressure on the dairy industry to reduce its environmental impact increases, efficient recycling of manure nutrients through local cropping systems becomes crucial. The aim of this study was to calculate annual nitrogen (N) and phosphorus (P) budgets in six counties located in [...] Read more.
As pressure on the dairy industry to reduce its environmental impact increases, efficient recycling of manure nutrients through local cropping systems becomes crucial. The aim of this study was to calculate annual nitrogen (N) and phosphorus (P) budgets in six counties located in the Magic Valley, Idaho and estimate what distance manure would need to be transported to be in balance with crop nutrient demand given current dairy cattle populations and cropping systems. Our analysis suggests that crop N needs will not be met solely by manure, and synthetic fertilizer will need to be applied. However, to balance P with crop production, manure would need to be transported a minimum of 12.9 km from dairies and would have to replace synthetic fertilizer P on 91% of regional cropland. Education of producers and technical specialists would be necessary to improve the management of manure use in regional cropping systems. Technical solutions such as alternative diets for cattle and nutrient capture from manure streams will also likely be necessary to bring regional P into balance to protect environmental quality and improve the sustainability of the regional dairy industry. Full article
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Review
The Evolution of Phenolic Compounds in Vitis vinifera L. Red Berries during Ripening: Analysis and Role on Wine Sensory—A Review
Agronomy 2021, 11(5), 999; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050999 - 18 May 2021
Cited by 1 | Viewed by 468
Abstract
The study of phenolic maturity in Vitis vinifera L. requires a multidisciplinary approach to understand how the evolution of berry flavonoids and cell wall material influence the colour and the textures of red wine. This is a challenging issue which involves researchers of [...] Read more.
The study of phenolic maturity in Vitis vinifera L. requires a multidisciplinary approach to understand how the evolution of berry flavonoids and cell wall material influence the colour and the textures of red wine. This is a challenging issue which involves researchers of viticulture and enology, and the results of their work are of particular interest for the producers of high-quality red wines. This review reports the current knowledge regarding phenolic maturity, describing the sensorial traits of the different compounds, the evolution of berry flavonoids and the methodologies used to evaluate their characteristics. Finally, the role of cell wall material in influencing the extractability of anthocyanins and proanthocyanidins was shown. By means of a critical review of the results, it can be hypothesised that prolonged ripening improved colour characteristics and mouthfeel properties, thanks to the higher amounts of extractable skin flavonoids associated with lower amounts of seed proanthocyanidins, and to the increased affinity of the cell wall material for the proanthocyanidins most involved in the perception of unpleasant astringency. Full article
Article
Effect of Re-Used Lignite and Mineral Wool Growing Mats on Plant Growth, Yield and Fruit Quality of Cucumber and Physical Parameters of Substrates in Hydroponic Cultivation
Agronomy 2021, 11(5), 998; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050998 - 18 May 2021
Viewed by 592
Abstract
In hydroponic cultivation of vegetables with a solid substrate, mineral wool predominates. The pro-ecological policy and consumers’ expectations cause an increase in interest in organic substrates, which, when properly used, are less harmful to the environment. The aim of this study was to [...] Read more.
In hydroponic cultivation of vegetables with a solid substrate, mineral wool predominates. The pro-ecological policy and consumers’ expectations cause an increase in interest in organic substrates, which, when properly used, are less harmful to the environment. The aim of this study was to determine the effect of reusing lignite substrate in hydroponic cultivation on the growth, yield and quality of cucumber fruit and on the physical parameters of the substrate. The greenhouse cucumber cultivar ‘Mewa F1’ with semi-long fruits and smooth skin was used for the study. The plants were grown in the ‘Carbomat’ lignite substrate and ‘Grotop Master’ rockwool in two cycles. In cycle 1, new growing mats were used, while in cycle 2 the same growing mats as in cycle 1 were used again. In the hydroponic cultivation carried out on mineral wool and in the lignite substrate, both in the new and the reused substrate, the cucumber obtained mostly similar plant growth parameters and fruit color. Cucumber grown on the new mineral wool had a higher number and weight of fruits, which were characterized by a higher content of β-carotene and lutein compared to fruits from plants grown in the new lignite substrate. On the other hand, the reused lignite substrate resulted in higher cucumber yields and fruits with higher firmness and higher carotenoid content compared to cucumber grown on reused mineral wool. At the same time, the content of dry matter and sugar extract in fruits obtained from plants growing in the new and reused lignite substrate was higher compared to fruits grown in mineral wool. Both new and reused lignite substrate were characterized by very low plant-available water content. In contrast; the air and water holding capacity of lignite after cultivation did not change as much as that of mineral wool. Full article
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Article
Influence of Nitrogen, Calcium and Nano-Fertilizer on Strawberry (Fragaria × ananassa Duch.) Fruit Inner and Outer Quality
Agronomy 2021, 11(5), 997; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050997 - 18 May 2021
Viewed by 434
Abstract
The production system, especially fertilisation has an important effect on yield and quality of strawberries. In the present study, plants were fertilized with different doses of nitrogen (0–100% recommended doses), calcium chelate, as well as nano fertilizer Lithovit. Strawberry cultivar ‘Clery’ yield and [...] Read more.
The production system, especially fertilisation has an important effect on yield and quality of strawberries. In the present study, plants were fertilized with different doses of nitrogen (0–100% recommended doses), calcium chelate, as well as nano fertilizer Lithovit. Strawberry cultivar ‘Clery’ yield and quality parameters (fruit color and firmness) including nutritional indicators (total soluble solids, sugars, organic acids, phenolic and volatile compounds) were monitored. Volatiles were identified and monitored using headspace solid phase microextraction and analysed using gas chromatograph-mass spectrometry (SPME/GC-MS) and sugars, organic acids, and phenolic compounds with high performance liquid chromatography. Organic acids and phenolic compounds were detected with mass spectrometer (HPLC/MS). Both nitrogen and calcium fertilisation had altered sugars, organic acids, volatile and phenolic contents in strawberry fruits. Fertilisation with higher doses of nitrogen and calcium increased the content of unpleasant aromas aldehydes hexanal (up to 3.8-fold) and (E)-2-hexen-1- (up to 3.7-fold). The content of fruity esters was uppermost in fruits fertilised with nano-fertiliser Lithovit (up to 2.3-fold). Fertilisation with N and Ca decreased the strength of ketone and terpenoids fruity aroma. The highest content of total phenols, as well as all individual hydroxycinnamic and hydroxybenzoic acid derivatives were obtained in the nano-fertiliser Lithovit treatment. Fertilisation, especially with nitrogen, had mostly negative impact on strawberry flavour while nano-fertilization with Lithovit improved strawberry phenolic content and aroma. Full article
(This article belongs to the Special Issue Preharvest Practices for High-Quality Strawberry Production)
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Article
Sustainable Agronomic Valorization of Unsulfured Molasses and Defatted Soybean Meal as an Optimized Formulation of Bio-Organic Fertilizer Enriched with High Cell Density P-Solubilizing Bacteria
Agronomy 2021, 11(5), 996; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050996 - 18 May 2021
Viewed by 568
Abstract
The application of plant beneficial bioinoculants such as phosphate solubilizing bacteria is a sustainable approach to expanding crop performance in agriculture. However, bioinoculant strains, particularly non-sporulating bacteria are often exposed to detrimental conditions throughout the production process and a long period of storage. [...] Read more.
The application of plant beneficial bioinoculants such as phosphate solubilizing bacteria is a sustainable approach to expanding crop performance in agriculture. However, bioinoculant strains, particularly non-sporulating bacteria are often exposed to detrimental conditions throughout the production process and a long period of storage. This will negatively influence their viable cell density and eventually limit its efficacy in the field. To overcome such a scenario, an optimal formulation of biofertilizer should be prioritized. In this report, a sustainable valorization of molasses and defatted soybean meal as formulation of biofertilizer enriched with Enterobacter hormaechei 40a was proposed. Through the two-level factorial design and central composite design, the optimal formulation and fermentation conditions of bio-organic fertilizer to achieve maximum cell density of strain 40a were achieved. The highest cell density of strain 40a in the optimized molasses-DSM (OMD) medium was 12.56 log CFU/mL after 24 h which was 99.7% accuracy towards the predicted value. Interestingly, the solubilized P was increased by 62.4% in the OMD medium (174.07 µg/mL P) as compared to the standard P medium (65.38 µg/mL P). The shelf life of strain 40a after 180 days of storage was improved significantly around 10 log CFU/mL, when the OMD medium was amended with 0.1% sodium alginate. The strategy described here offers opportunities for agronomic formulation and large-scale bio-organic fertilizer production in the agriculture industry. Full article
(This article belongs to the Special Issue Development and Application of Sustainable Organic Fertilizer)
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Article
Characterization of Maize Genotypes (Zea mays L.) for Resistance to Striga asiatica and S. hermonthica and Compatibility with Fusarium oxysporum f. sp. strigae (FOS) in Tanzania
Agronomy 2021, 11(5), 1004; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051004 - 18 May 2021
Viewed by 437
Abstract
Striga species cause significant yield loss in maize varying from 20 to 100%. The aim of the present study was to screen and identify maize genotypes with partial resistance to S. hermonthica (Sh) and S. asiatica (Sa) and compatible [...] Read more.
Striga species cause significant yield loss in maize varying from 20 to 100%. The aim of the present study was to screen and identify maize genotypes with partial resistance to S. hermonthica (Sh) and S. asiatica (Sa) and compatible with Fusarium oxysporum f. sp. strigae (FOS), a biocontrol agent. Fifty-six maize genotypes were evaluated for resistance to Sh and Sa, and FOS compatibility. Results showed that FOS treatment significantly (p < 0.001) enhanced Striga management compared to the untreated control under both Sh and Sa infestations. The mean grain yield was reduced by 19.13% in FOS-untreated genotypes compared with a loss of 13.94% in the same genotypes treated with FOS under Sh infestation. Likewise, under Sa infestation, FOS-treated genotypes had a mean grain yield reduction of 18% while untreated genotypes had a mean loss of 21.4% compared to the control treatment. Overall, based on Striga emergence count, Striga host damage rating, grain yield and FOS compatibility, under Sh and Sa infestations, 23 maize genotypes carrying farmer preferred traits were identified. The genotypes are useful genetic materials in the development of Striga-resistant cultivars in Tanzania and related agro-ecologies. Full article
Article
Impact of Leaf Occlusions on Yield Assessment by Computer Vision in Commercial Vineyards
Agronomy 2021, 11(5), 1003; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051003 - 18 May 2021
Viewed by 429
Abstract
Yield assessment has been identified as critical topic for grape and wine industry. Computer vision has been applied for assessing yield, but the accuracy was greatly affected by fruit occlusion affected by leaves and other plant organs. The objective of this work was [...] Read more.
Yield assessment has been identified as critical topic for grape and wine industry. Computer vision has been applied for assessing yield, but the accuracy was greatly affected by fruit occlusion affected by leaves and other plant organs. The objective of this work was the consistent, continuous evaluation of the impact of leaf occlusions in different commercial vineyard plots at different defoliation stages. RGB (red, green and blue) images from five Tempranillo (Vitis vinifera L.) vineyards were manually acquired using a digital camera under field conditions at three different levels of defoliation: no defoliation, partial defoliation and full defoliation. Computer vision was used for the automatic detection of different canopy features, and for the calibration of regression equations for the prediction of yield computed per vine segment. Leaf occlusion rate (berry occlusion affected by leaves) was computed by machine vision in no defoliated vineyards. As occlusion rate increased, R2 between bunch pixels and yield was gradually reduced, ranging from 0.77 in low occlusion, to 0.63. Full article
(This article belongs to the Special Issue Sustainable Viticulture Production and Vineyard Management Practices)
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Article
Automated Detection of Tetranychus urticae Koch in Citrus Leaves Based on Colour and VIS/NIR Hyperspectral Imaging
Agronomy 2021, 11(5), 1002; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051002 - 18 May 2021
Viewed by 501
Abstract
Tetranychus urticae Koch is an important citrus pest that produces chlorotic spots on the leaves and scars on the fruit of affected trees. It is detected by visual inspection of the leaves. This work studies the potential of colour and hyperspectral imaging (400–1000 [...] Read more.
Tetranychus urticae Koch is an important citrus pest that produces chlorotic spots on the leaves and scars on the fruit of affected trees. It is detected by visual inspection of the leaves. This work studies the potential of colour and hyperspectral imaging (400–1000 nm) under laboratory conditions as a fast and automatic method to detect the damage caused by this pest. The ability of a traditional vision system to differentiate this pest from others, such as Phyllocnistis citrella, and other leaf problems such as those caused by nutritional deficiencies, has been studied and compared with a more advanced hyperspectral system. To analyse the colour images, discriminant analysis has been used to classify the pixels as belonging to either a damaged or healthy leaves. In contrast, the hyperspectral images have been analysed using PLS DA. The rate of detection of the damage caused by T. urticae with colour images reached 92.5%, while leaves that did not present any damage were all correctly identified. Other problems such as damage by P. citrella were also correctly discriminated from T. urticae. Moreover, hyperspectral imaging allowed damage caused by T. urticae to be discriminated from healthy leaves and to distinguish between recent and mature leaves, which indicates whether it is a recent or an older infestation. Furthermore, good results were achieved in the discrimination between damage caused by T. urticae, P. citrella, and nutritional deficiencies. Full article
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Article
A Novel Pinkish-White Flower Color Variant Is Caused by a New Allele of Flower Color Gene W1 in Wild Soybean (Glycine soja)
Agronomy 2021, 11(5), 1001; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051001 - 18 May 2021
Viewed by 421
Abstract
The enzyme flavonoid 3′,5′-hydroxylase (F3′5′H) plays an important role in producing anthocyanin pigments in soybean. Loss of function of the W1 locus encoding F3′5′H always produces white flowers. However, few color variations have been reported in wild soybean. In the present study, we [...] Read more.
The enzyme flavonoid 3′,5′-hydroxylase (F3′5′H) plays an important role in producing anthocyanin pigments in soybean. Loss of function of the W1 locus encoding F3′5′H always produces white flowers. However, few color variations have been reported in wild soybean. In the present study, we isolated a new color variant of wild soybean accession (IT261811) with pinkish-white flowers. We found that the flower’s pinkish-white color is caused by w1-s3, a single recessive allele of W1. The SNP detected in the mutant caused amino acid substitution (A304S) in a highly conserved SRS4 domain of F3′5′H proteins. On the basis of the results of the protein variation effect analyzer (PROVEAN) tool, we suggest that this mutation may lead to hypofunctional F3′5′H activity rather than non-functional activity, which thereby results in its pinkish-white color. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
The Influence of Soil Tillage System on Changes in Gas Exchange Parameters of Pisum sativum L.
Agronomy 2021, 11(5), 1000; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11051000 - 18 May 2021
Viewed by 462
Abstract
A field experiment was carried out in 2017–2019 as a split-plot design with four replicates at the Agricultural Experimental Station in Grabów, Poland. The aim of the study was to compare the gas exchange parameters of the pea depending on the use of [...] Read more.
A field experiment was carried out in 2017–2019 as a split-plot design with four replicates at the Agricultural Experimental Station in Grabów, Poland. The aim of the study was to compare the gas exchange parameters of the pea depending on the use of different soil tillage systems. Physiological plant parameters as: net photosynthetic rate (PN), transpiration rate (E), stomatal conductance (gs), intercellular CO2 concentration (Ci) and relative chlorophyll content were measured in three developmental stages. The study have showed that all the measured parameters were affected by the tillage system of the soil. Net photosynthetic rate and transpiration rate were significantly lower in the treatments, where simplified-tillage was applied. Pea grown in the plough tillage (CT) showed a generally higher rate of net photosynthesis and transpiration rate compared to that of peas grown in the reduced tillage and no-tillage systems, but this was dependent on the plant development stage and the weather conditions prevailing in a given year. The highest intercellular CO2 concentration (Ci) under different cultivation methods were found in the no-tillage system, regardless of the developmental stage of legumes. The values of determination coefficients showed a positive relationship between the photosynthetic rate and seed yield of the peas tested in all the years of the research. The study also showed that a significantly higher SPAD index was found in the CT tillage system, irrespectively on the developmental stage. Full article
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Article
Estimation of the Genetic Diversity and Population Structure of Thailand’s Rice Landraces Using SNP Markers
Agronomy 2021, 11(5), 995; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050995 - 17 May 2021
Viewed by 676
Abstract
Rice is a staple food for more than half of the world’s population. Modern rice varieties have been developed for high yield and quality; however, there has been a substantial loss of diversity. A greater number of genetically dynamic landraces could offer valuable [...] Read more.
Rice is a staple food for more than half of the world’s population. Modern rice varieties have been developed for high yield and quality; however, there has been a substantial loss of diversity. A greater number of genetically dynamic landraces could offer valuable and useful genetic resources for rice improvement. In this study, the genetic diversity and population structure of 365 accessions of lowland and upland landraces from four populations from different geographical regions of Thailand were investigated using 75 SNP markers. Clustering analyses using maximum likelihood, Principal Coordinate Analysis (PCoA), and Discriminant Analysis of Principal Components (DAPC) clustered these landraces into two main groups, corresponding to indica and japonica groups. The indica group was further clustered into two subgroups according to the DAPC and STRUCTURE analyses (K = 3). The analysis of molecular variance (AMOVA) analysis results revealed that 91% of the variation was distributed among individuals, suggesting a high degree of genetic differentiation among rice accessions within the populations. Pairwise FST showed the greatest genetic differentiation between the northeastern and southern populations and the smallest genetic differentiation between the northern and northeastern populations. Isolation-by-distance analysis based on a Mantel test indicated a significant relationship between the genetic distance and geographic distance among the Thai rice landraces. The results from this study provide insight into the genetic diversity of Thai rice germplasm, which will enhance the germplasm characterization, conservation, and utilization in rice genetics and breeding. Full article
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Article
Influence of Compost from Post-Consumer Wood on Development, Nutrition State of Plants, Microbiological and Biochemical Parameters of Substrates in Zonal Pelargonium (Pelargonium zonale)
Agronomy 2021, 11(5), 994; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050994 - 17 May 2021
Viewed by 417
Abstract
The purpose of this study was to assess the possibility of using compost made from post-consumer wood in zonal pelargonium (Pelargonium zonale) cv. ‘Tex Mex’ cultivation. The influence of compost on the plant’s development and nutritional state, as well as the [...] Read more.
The purpose of this study was to assess the possibility of using compost made from post-consumer wood in zonal pelargonium (Pelargonium zonale) cv. ‘Tex Mex’ cultivation. The influence of compost on the plant’s development and nutritional state, as well as the microbiological and enzymatic activity of the substrate was examined. Two variants of compost marked with the following letters: OPA and OPB were used. Both variants consisted of post-consumer wood waste (OP) (70% of weight) mixed with powdery waste from processing MDF boards (6%), mature compost from fiberboard waste (19%), high peat (4%), water and a biological inoculum “Activit Las”. Thirty kilograms of urea in two portions per prism were added to the OPA variant while ammonium nitrate (1.5 kg per prism), magnesium sulphate (0.4 kg per prism), potassium phosphate (0.8kg per prism) and calcium phosphate (0.9 kg per prism) were added to the OPB variant. The plants were cultivated into pots 12 cm in diameter and a capacity of 659 dm3 in the substrates consisting of peat with the addition of compost at different volume ratios. It was found that the medium type had a significant influence on the growth and flowering of the zonal pelargonium. The type of compost used was the determinant for microbiological total counts and activity. The chemical composition of the substrates significantly modified the plants’ nutritional state in terms of macro- and microelements. In summary, the study demonstrated that good quality ornamental plants can be successfully grown in peat substrate containing 25% or 50% of post-consumer wood compost. Full article
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Review
Biochar and Its Broad Impacts in Soil Quality and Fertility, Nutrient Leaching and Crop Productivity: A Review
Agronomy 2021, 11(5), 993; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050993 - 17 May 2021
Cited by 2 | Viewed by 673
Abstract
Biochar is gaining significant attention due to its potential for carbon (C) sequestration, improvement of soil health, fertility enhancement, and crop productivity and quality. In this review, we discuss the most common available techniques for biochar production, the main physiochemical properties of biochar, [...] Read more.
Biochar is gaining significant attention due to its potential for carbon (C) sequestration, improvement of soil health, fertility enhancement, and crop productivity and quality. In this review, we discuss the most common available techniques for biochar production, the main physiochemical properties of biochar, and its effects on soil health, including physical, chemical, and biological parameters of soil quality and fertility, nutrient leaching, salt stress, and crop productivity and quality. In addition, the impacts of biochar addition on salt-affected and heavy metal contaminated soils were also reviewed. An ample body of literature supports the idea that soil amended with biochar has a high potential to increase crop productivity due to the concomitant improvement in soil structure, high nutrient use efficiency (NUE), aeration, porosity, and water-holding capacity (WHC), among other soil amendments. However, the increases in crop productivity in biochar-amended soils are most frequently reported in the coarse-textured and sandy soils compared with the fine-textured and fertile soils. Biochar has a significant effect on soil microbial community composition and abundance. The negative impacts that salt-affected and heavy metal polluted soils have on plant growth and yield and on components of soil quality such as soil aggregation and stability can be ameliorated by the application of biochar. Moreover, most of the positive impacts of biochar application have been observed when biochar was applied with other organic and inorganic amendments and fertilizers. Biochar addition to the soil can decrease the nitrogen (N) leaching and volatilization as well as increase NUE. However, some potential negative effects of biochar on microbial biomass and activity have been reported. There is also evidence that biochar addition can sorb and retain pesticides for long periods of time, which may result in a high weed infestation and control cost. Full article
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Article
Open Field Simulating Nocturnal Warming on Summer Maize Performance in the North China Plain
Agronomy 2021, 11(5), 992; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050992 - 17 May 2021
Viewed by 368
Abstract
Climate changes show asymmetrical warming, and warming is typically greater at night than during the day. To understand how nocturnal warming (NW) affects the performance of maize (Zea mays L.), an open-field experiment with a free air temperature increase (FATI) facility was [...] Read more.
Climate changes show asymmetrical warming, and warming is typically greater at night than during the day. To understand how nocturnal warming (NW) affects the performance of maize (Zea mays L.), an open-field experiment with a free air temperature increase (FATI) facility was conducted for three seasons during 2014 to 2016 at Luancheng eco-agro-experimental station on the North China Plain (NCP). Three nocturnal warming scenarios were set up: the entire growing period (T1, from V4 to maturity), only the vegetative stages (T2, from V4 to a week presilking) and the reproductive stages (T3, from a week presilking to R6). The treatment without NW was the control. Maize lodged seriously in 2015 due to heavy rainfall combined with strong winds, and the experiment failed. The results from 2014 and 2016 were analyzed in this study. During the experimental duration, the average nocturnal temperature was increased by approximately 3.6 and 3.3 °C at 150 cm height and 2.0 and 1.7 °C at the soil surface during the vegetative stages. The corresponding increases were 2.1 and 2.5 °C and 0.7 and 1.2 °C at the soil surface during the reproductive stages in 2014 and 2016, respectively, as compared with that of the CK treatment. NW during the whole growth period significantly decreased maize yield for the two seasons. Treatment T2 had a smaller impact on maize yield than T1 and T3. The silking stage was delayed by 2 days in 2014 and 2016 under T1. As a result, presilking duration and VT-R1 interval were prolonged by 1–2 days; and the postsilking duration were shortened by 1–3 days under T1. The soil moisture in the warmed plots was slightly lower than that in the control plots in the 2014 and during the stages before the earlier grain-filling stages in 2016, but NW decreased soil water content greatly at the later grain-filling stages in 2016, which caused the fast green leaf senescence and exacerbated the negative effects of NW on maize yield. NW for the whole growth duration (T1) significantly decreased seed weight and harvest index. NW increased leaf nighttime respiration rate in both seasons. No significant effects of NW on ear leaf net photosynthesis, leaf area, and specific leaf weight at early grain-filling stage were observed, irrespective of the warming stage and season. The results suggested that reproductive stages were more sensitive to NW compared to vegetative stages under the growing conditions of NCP. The negative effects of NW were worsened in dry seasons. The reduction in maize yield with nocturnal warming was driven by the reduction in the aboveground carbon allocation from shoot to grain during postanthesis stage. Full article
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Article
Diversity of Cowpea [Vigna unguiculata (L.) Walp] Landraces in Mozambique: New Opportunities for Crop Improvement and Future Breeding Programs
Agronomy 2021, 11(5), 991; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050991 - 17 May 2021
Cited by 1 | Viewed by 481
Abstract
Cowpea (Vigna unguiculata) is a neglected crop native to Africa, with an outstanding potential to contribute to the major challenges in food and nutrition security, as well as in agricultural sustainability. Two major issues regarding cowpea research have been highlighted in [...] Read more.
Cowpea (Vigna unguiculata) is a neglected crop native to Africa, with an outstanding potential to contribute to the major challenges in food and nutrition security, as well as in agricultural sustainability. Two major issues regarding cowpea research have been highlighted in recent years—the establishment of core collections and the characterization of landraces—as crucial to the implementation of environmentally resilient and nutrition-sensitive production systems. In this work, we have collected, mapped, and characterized the morphological attributes of 61 cowpea genotypes, from 10 landraces spanning across six agro-ecological zones and three provinces in Mozambique. Our results reveal that local landraces retain a high level of morphological diversity without a specific geographical pattern, suggesting the existence of gene flow. Nevertheless, accessions from one landrace, i.e., Maringué, seem to be the most promising in terms of yield and nutrition-related parameters, and could therefore be integrated into the ongoing conservation and breeding efforts in the region towards the production of elite varieties of cowpea. Full article
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Article
Climate Projections for Precipitation and Temperature Indicators in the Douro Wine Region: The Importance of Bias Correction
Agronomy 2021, 11(5), 990; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11050990 - 17 May 2021
Viewed by 524
Abstract
The implications of weather and climate extremes on the viticulture and winemaking sector can be particularly detrimental and acquire more relevance under a climate change context. A four-member ensemble of the Regional Climate Model-Global Climate Model chain simulations is used to evaluate the [...] Read more.
The implications of weather and climate extremes on the viticulture and winemaking sector can be particularly detrimental and acquire more relevance under a climate change context. A four-member ensemble of the Regional Climate Model-Global Climate Model chain simulations is used to evaluate the potential impacts of climate change on indices of extreme temperature and precipitation, as well as on agroclimatic indices of viticultural suitability in the Douro Wine Region, Portugal, under current and future climate conditions, following the RCP8.5 anthropogenic radiative forcing scenario. Historical (1989–2005) and future (2051–2080) periods are considered for this purpose. Although model outputs are bias-corrected to improve the accuracy of the results, owing to the sensitivity of the climatic indicators to the specific bias correction method, the performance of the linear and quantile mapping methods are compared. The results hint at the importance of choosing the most accurate method (quantile mapping), not only in replicating extremes events but also in reproducing the accumulated agroclimatic indices. Significant differences between the bias correction methods are indeed found for the number of extremely warm days (maximum temperature > 35 °C), number of warm spells, number of warm spell days, number of consecutive dry days, the Dryness Index, and growing season precipitation. The Huglin Index reveals lower sensitivity, thus being more robust to the choice of the method. Hence, an unsuitable bias correction method may hinder the accuracy of climate change projections in studies heavily relying on derived extreme indices and agroclimatic indicators, such as in viticulture. Regarding the climate change signal, significant warming and drying trends are projected throughout the target region, which is supported by previous studies, but also accompanied by an increase of intensity, frequency, and duration of extreme events, namely heatwaves and dry spells. These findings thereby corroborate the need to adopt timely and effective adaptation strategies by the regional winemaking sector to warrant its future sustainability and enhance climate resilience. Full article
(This article belongs to the Section Agricultural Engineering)
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