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Agronomy, Volume 11, Issue 10 (October 2021) – 197 articles

Cover Story (view full-size image): The Colorado potato beetle is a model for pest mismanagement, as it is highly adaptable and can rapidly develop insecticide resistance. Today, the control of CPB has become difficult due to the rapid evolution of its resistance to most insecticides through both cross-resistance and multiple resistance to different compounds. In the figure 3, known mechanisms of CPB resistance to insecticides include mutations in gene-encoding target receptors or enzymes (e.g., VGSCs and AChE), enhanced metabolism, reduced insecticide penetration, and increased excretion. This beetle has a significant negative impact on potato yield, and there is an urgent need for alternative, innovative strategies to combat CPB in a more environmentally friendly manner whilst considering sustainability. View this paper.
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Article
The Role of Cover Crop Types and Residue Incorporation in Improving Soil Chemical Properties
Agronomy 2021, 11(10), 2091; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102091 - 19 Oct 2021
Viewed by 441
Abstract
Soil chemical properties can be improved by incorporating crop residues in soil and letting it decompose. This study explored the use of incorporating residues of cover crops for improvements in soil chemical properties including soil organic matter (SOM), soil pH, and the selected [...] Read more.
Soil chemical properties can be improved by incorporating crop residues in soil and letting it decompose. This study explored the use of incorporating residues of cover crops for improvements in soil chemical properties including soil organic matter (SOM), soil pH, and the selected soil macro- and micronutrients in greenhouse and field trials. Factors of interest included (i) cover crops and their combinations and (ii) methods of crop termination and incorporation in soil (disc, mow + disc, glyphosate, roller crimper). The greenhouse trial showed up to a 20% higher amount of SOM accumulated in soils incorporated with crop residues. Buckwheat (3.12%) and phacelia (3.12%) produced significantly different and larger SOM than that of the control treatment that received no crop residues (p ≤ 0.05). The soil pH of the brown mustard treatment was also significantly affected by the experimental treatments (p ≤ 0.05). The incorporation of crop residues did not affect soil phosphorous (P) or potassium (K) concentrations, except for brown mustard, with significantly higher values of P and K than the control treatment. Calcium (Ca) was significantly higher in the soil of phacelia + pea treatment (p ≤ 0.05). Buckwheat + pea produced a higher concentration of Ca (1028 mg/kg) followed by buckwheat alone (1006 mg/kg). Analysis of variance (ANOVA) calculated on the results of the field trial showed that the mix treatment that had a mixture of four cover crops significantly increased the SOM content. Buckwheat produced the highest (2.95%) SOM, then brown mustard and timothy. This study concludes that, irrespective of the tillage incorporation methods, the residues from cover crops are a potential source of improvement in soil health, and this practice may promote sustainable agriculture in conditions similar to those in this study. Full article
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Article
The Use of New Parameters to Optimize the Composting Process of Different Organic Wastes
Agronomy 2021, 11(10), 2090; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102090 - 19 Oct 2021
Cited by 1 | Viewed by 354
Abstract
The correct development of the composting process is essential to obtain a product of high value from organic wastes. Nowadays, some composting mixture parameters (i.e., air-filled porosity, moisture and the C/N ratio) are used to optimize the composting process, but their suitability is [...] Read more.
The correct development of the composting process is essential to obtain a product of high value from organic wastes. Nowadays, some composting mixture parameters (i.e., air-filled porosity, moisture and the C/N ratio) are used to optimize the composting process, but their suitability is still debated because the literature reports contrasting results. This paper aimed to find other parameters that control the correct development of composting. The relationship between these and the compost quality was then verified. Twelve different composting mixtures were prepared using different organic wastes and bulking agents and were aerobically treated in a 300 L composter. The physico-chemical and chemical parameters of initial mixtures were analyzed, with particular regard to the total and water-extractable forms of organic C and N and their ratios and correlated with the temperature measured during composting. A positive correlation between temperature parameters during the active phase and soluble forms of N in the initial mixtures was found. A high total organic C to soluble N ratio in the composting mixtures was correlated with the low quality of the compost produced. Based on the results, a minimum content of WEN (water-extractable N) (0.4% w/w) or a TOC/WEN (total organic C/WEN) ratio in the range of 40–80 was recommended to ensure the correct development of the process and to produce compost of high quality. Full article
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Article
Combining Willow Compost and Peat as Media for Juvenile Tomato Transplant Production
Agronomy 2021, 11(10), 2089; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102089 - 19 Oct 2021
Viewed by 291
Abstract
In 2019–2020, a study was conducted to evaluate the suitability of willow composts as a substrate or substrate component in tomato transplant cultivation. In 2019, 4-year-old chopped willow biomass (mostly chips <2 cm long) was formed into four compost prisms: S0—willow compost without [...] Read more.
In 2019–2020, a study was conducted to evaluate the suitability of willow composts as a substrate or substrate component in tomato transplant cultivation. In 2019, 4-year-old chopped willow biomass (mostly chips <2 cm long) was formed into four compost prisms: S0—willow compost without additives; SN—willow compost with the addition of nitrogen; SF—willow compost with the addition of wood-decaying mycelium; and SFN—willow compost with the addition of wood-decaying mycelium and nitrogen. Willow compost was rated as a homogeneous substrate (S0, SN, SF, and SFN) and as a substrate component with peat (P), mixed in willow:peat ratios such as 25:75, 50:50, and 75:25, in the variants S0:P, SN:P, SF:P, and SFN:P. For reference, deacidified peat was used as a homogeneous substrate. The study showed that willow compost could be used as a renewable plant material replacing peat. The best parameters (plant height, leaf span, number of leaves, and especially the highest weight) were found in tomato transplants grown in the SF:P and SFN:P substrates and at a 25:75 ratio. It was found that the addition of nitrogen to the compost, in order to obtain a wide C:N ratio, negatively affected the initial growth of tomato plants. Full article
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Article
The Impact of Different Crop Rotations by Weed Management Strategies’ Interactions on Weed Infestation and Productivity of Wheat (Triticum aestivum L.)
Agronomy 2021, 11(10), 2088; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102088 - 19 Oct 2021
Viewed by 446
Abstract
Weed infestations significantly reduce the growth and yield of field crops. Herbicides are mostly used for weed management due to their quick results. However, resistant biotypes to available herbicides are rapidly increasing around the word. This situation calls for the development of alternative [...] Read more.
Weed infestations significantly reduce the growth and yield of field crops. Herbicides are mostly used for weed management due to their quick results. However, resistant biotypes to available herbicides are rapidly increasing around the word. This situation calls for the development of alternative weed management strategies. Crop rotation and allelopathic water extracts are regarded as the most important alternative weed management strategies. Therefore, this two-year study assessed the impact of different annual crop rotations by weed management strategies’ interactions on weed infestation and productivity of wheat crop. Wheat was planted in five rotations, i.e., (i) fallow-wheat, (ii) rice-wheat, (iii) cotton-wheat, (iv) mungbean-wheat and (v) sorghum-wheat. The weed management strategies included in the study were; (i) false seedbed, (ii) application of 12 L ha−1 allelopathic plant water extracts (1:1:1:1 ratio of sorghum, sunflower, mulberry and eucalyptus), (iii) herbicide application, (iv) weed-free (weed control) and (v) weedy-check (no weed control). Herbicide application was the most effective treatment in lowering weed densities and biomass during both years followed by false seedbed, while allelopathic crop water extracts were least effective. The lowest weed infestation was noted in sorghum-wheat rotation followed by cotton-wheat and mungbean-wheat, while fallow-wheat had the highest weed infestation. Weedy-check treatment caused significant reduction in wheat growth and yield, whereas the highest grain yield was recorded from weed-free and herbicide application treatments. Grain yield of wheat planted after sorghum was suppressed; however, yield improved when wheat was planted after mungbean. Planting wheat after mungbean in a weed-free environment, achieved through chemical and/or mechanical means, is the best strategy to obtain higher wheat yields. Full article
(This article belongs to the Special Issue Plant Interference through Competition and Allelopathy)
Article
Innovative Land Arrangement in Combination with Irrigation Methods Improves the Crop and Water Productivity of Rice (Oryza sativa L.) Grown with Okra (Abelmoschus esculentus L.) under Raised and Sunken Bed Systems
Agronomy 2021, 11(10), 2087; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102087 - 19 Oct 2021
Viewed by 390
Abstract
The underground water and water storage reservoirs are rapidly depleting due to nominal recharging by the rainfalls making water a scarce resource for irrigation resulting in poor crop growth and production. Irrigation water application should focus on the proficient use of each drop [...] Read more.
The underground water and water storage reservoirs are rapidly depleting due to nominal recharging by the rainfalls making water a scarce resource for irrigation resulting in poor crop growth and production. Irrigation water application should focus on the proficient use of each drop of water. Water productivity (WP) in agriculture can be improved through crop diversification, proper land and water management techniques. Considering this, a field investigation was carried out during 2013–2014 and 2014–2015 to study the crop response of rice (Oryza sativa L.) + okra (Abelmoschus esculentus L.) system to land configurations and irrigation regimes. Three raised-sunken beds (RSB) having width (m) ratios of 1:3, 2:3, 3:3 and two irrigation schedules viz. continuous standing water (CSW) of 5 ± 2 cm depth and alternate wetting and drying (AWD) at 3 ± 1 days interval for rice in sunken bed were tested. Rice yield was more (4.36 and 4.89 Mg ha−1) under CSW irrigation than AWD irrespective of raised bed width. The highest okra yield was noted by 14.09 and 15.43 Mg ha−1 with AWD in 1:3 RSB systems, whereas the lowest yield was recorded in CSW 1:3 RSB systems. Rice equivalent yield (REY) was found as the maximum in AWD than CSW irrespective of raised and sunken bed configurations. The AWD in 3:3 RSB systems exhibited the highest WP of 1.02 and 1.01 kg m−3 during the first and second year of study, respectively. Wider RSB system of land configuration ratio of 3:3 saved about 40–45% of irrigation water. Such information will help in the planning of an innovative intercropping system of summer rice + okra in the field by changing the land configuration to the raised bed and sunken bed with the AWD irrigation system. Full article
(This article belongs to the Special Issue Sustainable Tillage and Sowing Technologies)
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Article
Influence of Different Spent Mushroom Substrates on Yield, Morphological and Photosynthetic Parameters of Strawberry (Fragaria × ananassa Duch.)
Agronomy 2021, 11(10), 2086; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102086 - 19 Oct 2021
Viewed by 346
Abstract
The present study aimed to evaluate fresh spent mushroom substrate (SMS) as a growing medium in soilless strawberry cv. ‘Honeoye’ production. Fresh SMS after commercial production of Agaricus bisporus, Lentinus edodes, and Pleurotus ostreatus was used as a peat substitute in [...] Read more.
The present study aimed to evaluate fresh spent mushroom substrate (SMS) as a growing medium in soilless strawberry cv. ‘Honeoye’ production. Fresh SMS after commercial production of Agaricus bisporus, Lentinus edodes, and Pleurotus ostreatus was used as a peat substitute in 15 and 25% (v/v), for strawberry cultivation in an unheated plastic tunnel. In the experiment, seven different substrates were studied, including peat (100%) as control and six substrate combinations (prepared by mixing SMSs with peat). The study was carried out in a randomized complete block design in five replicates. The results indicated that the electrical conductivity (EC), pH, and nutrient content varied among the studied substrates. The experiment also demonstrated that the substrates significantly influenced strawberry yield, leaf area, and fresh and dry plant weights. However, no significant differences were observed for selected photosynthetic parameters (Fv/Fm, Fv/F0, and PIabs) and Normalized Difference Vegetation Index (NDVI) values among the evaluated substrates. Differences were recorded for the Photochemical Reflectance Index (PRI) and Modified Chlorophyll Absorption in Reflectance Index (MCARI) values. The present investigation revealed that fresh SMSs can be an effective and inexpensive peat substitute in 15 and 25% (v/v). Therefore, such easy and immediate utilisation of SMSs could overcome associated disposal problems. Full article
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Article
Expansion of Native Plant Stellera chamaejasme L. Alters the Structure of Soil Diazotrophic Community in a Salinized Meadow Grassland, Northeast China
Agronomy 2021, 11(10), 2085; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102085 - 19 Oct 2021
Viewed by 269
Abstract
The invasion of native plants has posed a serious risk to species diversity and ecosystem function. How they modify underground community and facilitate successful invasion remain unknown. Soil diazotrophs may play an important role in invasion by native plants. Stellera chamaejasme L. has [...] Read more.
The invasion of native plants has posed a serious risk to species diversity and ecosystem function. How they modify underground community and facilitate successful invasion remain unknown. Soil diazotrophs may play an important role in invasion by native plants. Stellera chamaejasme L. has expanded within around the heavily degraded Horqin Grassland in northeast China in recent decades. This study aims to detect the effect of the expansion of S. chamaejasme L. on soil diazotrophic community structure through high-throughput sequencing and examine the relationship between diazotrophic community structure and soil physicochemical properties. An extensive increase in S. chamaejasme population induced significant changes in soil diazotrophic community and marked shifts in the relative abundances of Bradyrhizobium and Desulfuromonas. Soil organic matter (SOM), total nitrogen, NO3-N, and electrical conductivity (EC) increased, whereas NH4+-N and pH significantly decreased in soil invaded by S. chamaejasme. The diazotrophic community structure was correlated with SOM, nitrogen content, EC, and pH. The relative abundances of Bradyrhizobium and Desulfuromonas were significant negatively and positively correlated with soil EC, respectively. This study suggests that the interaction between S. chamaejasme and soil diazotrophic microbes and the durative increase in soil EC may facilitate invasion by this S. chamaejasme population. Full article
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Article
Efficacy of Various Mechanical Weeding Methods—Single and in Combination—In Terms of Different Field Conditions and Weed Densities
Agronomy 2021, 11(10), 2084; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102084 - 19 Oct 2021
Viewed by 385
Abstract
Public awareness and environmental policies have increased interest in applying non-herbicide weed control methods in conventional farming systems. Even though mechanical weed control has been used for centuries in agricultural practice, continuous developments—both in terms of implements and automation technologies—are continuously improving the [...] Read more.
Public awareness and environmental policies have increased interest in applying non-herbicide weed control methods in conventional farming systems. Even though mechanical weed control has been used for centuries in agricultural practice, continuous developments—both in terms of implements and automation technologies—are continuously improving the potential outcomes. Current mechanical weed control methods were evaluated for their weed control efficacy and effects on yield potential against their equivalent herbicide methods. Furthermore, not much is known about the correlation between weed control efficacy (WCE) of different mechanical methods at varying weed density levels. A total of six experiments in winter wheat (2), peas (2), and soybean (2) were carried out in the years 2018, 2019, and 2020 in southwestern Germany. Harrowing and hoeing treatments at different speeds were carried out and compared to the herbicide treatments and untreated control plots. Regarding the average WCE, the combination of harrowing and hoeing was both the strongest (82%) and the most stable (74–100%) mechanical treatment in the different weed density levels. Whereas, in average, hoeing (72%) and harrowing (71%) were on the same WCE level, but harrowing (49–82%) was more stable than hoeing (40–99%). The grain yields in winter wheat varied between 4.1 Mg∙ha−1 (control) and 6.3 Mg∙ha−1 (harrow), in pea between 2.8 Mg∙ha−1 (hoe slow) and 5.7 Mg∙ha−1 (hoe fast) and in soybean between 1.7 Mg∙ha−1 (control) and 4 Mg∙ha−1 (herbicide). However, there were no significant differences in most cases. The results have shown that it is not possible to pinpoint a specific type of treatment as the most appropriate method for this cultivation, across all of the different circumstances. Different field and weather conditions can heavily affect and impact the expected outcome, giving, each time, an advantage for a specific type of treatment. Full article
(This article belongs to the Special Issue Application of Sensors for Mechanical Weed Control)
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Article
Understanding Growth Rate Patterns among Different Drought Resistant Sugarcane Cultivars during Plant and Ratoon Crops Encountered Water Deficit at Early Growth Stage under Natural Field Conditions
Agronomy 2021, 11(10), 2083; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102083 - 19 Oct 2021
Viewed by 404
Abstract
Drought-tolerant sugarcane genotypes have been proposed to alleviate the issue of early water deficits; however, it is important to investigate the impact of phenology on the crop growth rate and growth patterns. This study aimed to investigate the responses of different water deficit-tolerant [...] Read more.
Drought-tolerant sugarcane genotypes have been proposed to alleviate the issue of early water deficits; however, it is important to investigate the impact of phenology on the crop growth rate and growth patterns. This study aimed to investigate the responses of different water deficit-tolerant cultivars on crop growth rate patterns of both plant crop and ratoon under rain-fed and well-irrigated conditions, and to determine the relationship between final stalk dry weight and crop growth rates during water deficit, recovery, and maturity phases. A 2 × 6 split plot in a randomized complete block design with four replications was used. Two water regimes, namely, field capacity (FC) and rain-fed conditions, were assigned as the main plot, whereas six sugarcane cultivars differing in water deficit-tolerant levels were assigned as sub-plots. Sugarcane cultivar KK3 consistently possessed high potential and low reduction in dried shoot weight. A correlation was found between stalk dry weight and stem growth rate, shoot growth rate, and height growth rate (HGR) during the recovery period in the first season, and HGR at the recovery stage was correlated with the dry weight of ratoon. The recovery phase of early water deficit stress was a key stage for determining the final stalk dry matter. The desired cultivars having a good adaptation to water deficit stress at the formative stage, such as KK3, showed a gradually increased growth rate during the early water deficit stage, but this growth accelerated, and the maximum growth rate was reached, during the recovery period. This knowledge will help to clarify the selection of sugarcane cultivars in breeding programs that can resist water deficit at the early growth stage. Full article
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Article
Nutrient Release and Ammonia Volatilization from Biochar-Blended Fertilizer with and without Densification
Agronomy 2021, 11(10), 2082; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102082 - 18 Oct 2021
Viewed by 460
Abstract
Blending fertilizer with biochar followed by densification to make it into a tablet can enhance the adsorption of fertilizer on the biochar surface and reduce the nutrient loss during handling. However, the nutrient release and ammonia volatilization from biochar-blended fertilizer with and without [...] Read more.
Blending fertilizer with biochar followed by densification to make it into a tablet can enhance the adsorption of fertilizer on the biochar surface and reduce the nutrient loss during handling. However, the nutrient release and ammonia volatilization from biochar-blended fertilizer with and without densification are not well understood. The objectives of this study were to determine the nutrient release and ammonia volatilization from an acid soil applied with biochar-blended NPK fertilizer with and without densification. The nutrient release of biochar-blended NPK was determined using water incubation for 30 days, whereas daily loss of ammonia was measured using a closed dynamic air flow system for 10 days. The densified biochar-blended NPK caused stronger physical binding of the nutrients within the tablet in addition to stronger chemical bondings between the nutrients with the biochar’s functional groups. As a result, nutrient release in the water incubation from the biochar-blended NPK fertilizer tablet was slower. However, blending the biochar with the NPK fertilizer increased soil ammonia volatilization relative to the NPK fertilizer alone. This demonstrates that the biochar-blended fertilizer tablet has the potential to serve as a slow release fertilizer for crop cultivation. Full article
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Review
Co-Application of Charcoal and Wood Ash to Improve Potassium Availability in Tropical Mineral Acid Soils
Agronomy 2021, 11(10), 2081; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102081 - 18 Oct 2021
Viewed by 540
Abstract
Potassium (K) is a macronutrient required by plants for energy production, enzyme activation, formation of cell wall, production of protein, and photosynthesis. However, K in the soil solution is leached from the rhizosphere before it interacts with soil colloids because of the abundance [...] Read more.
Potassium (K) is a macronutrient required by plants for energy production, enzyme activation, formation of cell wall, production of protein, and photosynthesis. However, K in the soil solution is leached from the rhizosphere before it interacts with soil colloids because of the abundance of kaolinite clay minerals in mineral acid soils such as Ultisols and Oxisols. These soils are highly weathered, low in organic matter, low in pH, but high aluminium (Al), and iron (Fe) ions. As a result, K becomes unavailable for plants, and this affects crop production and farmers’ profitability. This problem has steered the attention to the application of amendments to minimise K loss. Animal manures, plant residues, and composts applications are some of the corrective measures taken to improve the K availability in tropical acid soils. However, there is dearth of information on co-application of charcoal and wood ash as soil amendments to improve the K availability and the changes they cause to the dynamic equilibrium of K in mineral acid soils. Hence, this review discusses the dynamics, availability of K, and proposed mechanisms involved when charcoal and wood ash are used to amend tropical acid soils. The optimisation and understanding of the role of charcoal and wood ash co-application as soil amendments have potential benefits to improve the K availability and physicochemical properties of mineral acid soils. Full article
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Article
Biochemical and Physiological Responses of Thermostable Wheat Genotypes for Agronomic Yield under Heat Stress during Reproductive Stages
Agronomy 2021, 11(10), 2080; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102080 - 18 Oct 2021
Viewed by 316
Abstract
Wheat is a globally important crop used as a main staple food in various countries of the world. The current study was conducted with the objective to evaluate the effect of a high temperature (HT) on osmolytes (starch, sucrose, total soluble sugars, total [...] Read more.
Wheat is a globally important crop used as a main staple food in various countries of the world. The current study was conducted with the objective to evaluate the effect of a high temperature (HT) on osmolytes (starch, sucrose, total soluble sugars, total soluble proteins and proline), physiological parameters (Chl-a, Chl-b, photosynthesis rate, transpiration rate and stomatal conductance), antioxidant enzymes (superoxide dismutase, catalase and peroxidase) and agronomic traits (flag leaf area, spike length, and thousand grain weight) during the grain filling and anthesis stages of wheat cultivars (Fakhr-e-Bhakar, Raj-3765, Jimai-22 and Bayraktar-2000) collected from different regions of the world. Separate experiments for both stages were conducted in a glasshouse and treated with two different temperature regimes, i.e., optimum (OT) (24 °C day; 14 °C night) and high temperature (HT) (32 °C day; 22 °C night) in RCBD for two weeks. The data for osmolytes, antioxidant enzymes and physiological contents were collected at days 3, 5, 7, 9 and 13 after the start of plant stress, while the agronomic traits were collected at maturity. The data obtained were subjected to a statistical analysis using the statistix8.1 and R-program. HT stress significantly reduced all the traits except for the membrane damage, transpiration rate, proline and total soluble sugars, whose values increased considerably in the genotype Bayraktar-2000. However, under both regimes of temperature Fakhr-e-Bhakkar showed a high tolerance against HT stress, as revealed by physiological, biochemical and agronomic evaluations. Moreover, correlation, PCA and heat map analyses indicated that all types of traits are significantly interconnected in determining the crop potential to sustain its growth under HT stress. Full article
(This article belongs to the Special Issue Crop Physiological Responses to Abiotic Stress Factors)
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Article
Agronomic Effects of Tectona grandis Biochar from Wood Residues on the Growth of Young Cedrela odorata Plants in a Nursery
Agronomy 2021, 11(10), 2079; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102079 - 18 Oct 2021
Viewed by 408
Abstract
Biochar from agroforestry biomass residues is an alternative source of fertilizers for improving the soil fertility. In Costa Rica, Cedrela odorata is planted in pure plantations and agroforestry systems and different types of substrates are used in the nursery to enhance the growth [...] Read more.
Biochar from agroforestry biomass residues is an alternative source of fertilizers for improving the soil fertility. In Costa Rica, Cedrela odorata is planted in pure plantations and agroforestry systems and different types of substrates are used in the nursery to enhance the growth and performance of the young saplings. The main objective of the present study was to evaluate the growth (in height, diameter, biomass) and distribution of carbon (C), hydrogen (H), and nitrogen (N) for C. odorata plants in a nursery with different application rates of biochar produced from Tectona grandis wood residues. The results showed that the above-measured variables were statistically affected by different application rates of the biochar. The stem diameter, total height, number of leaves, and height increment were statistically significantly higher in the substrate with an application rate of 25–50 tons/ha, in contrast to the 0 and 75 tons/ha application rates, which were statistically the lowest. As for the levels of C, H, and N, there were differences, with the highest values of N and C being in the leaves and stem with the 50 tons/ha application rate and the highest values of H for the 75 tons/ha application rate. The above results showed that applying biochar obtained from T. grandis residues improved soil conditions, resulting in better growth of C. odorata saplings with an application rate of 25 and 50 tons/ha. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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Article
Detection of Crop Hail Damage with a Machine Learning Algorithm Using Time Series of Remote Sensing Data
Agronomy 2021, 11(10), 2078; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102078 - 18 Oct 2021
Viewed by 528
Abstract
Hailstorms usually result in total crop loss. After a hailstorm, the affected field is inspected by an insurance claims adjuster to assess yield loss. Assessment accuracy depends largely on in situ detection of homogeneous damage sectors within the field, using visual techniques. This [...] Read more.
Hailstorms usually result in total crop loss. After a hailstorm, the affected field is inspected by an insurance claims adjuster to assess yield loss. Assessment accuracy depends largely on in situ detection of homogeneous damage sectors within the field, using visual techniques. This paper presents an algorithm for the automatic detection of homogeneous hail damage through the application of unsupervised machine learning techniques to vegetation indices calculated from remote sensing data. Five microwave and five spectral indices were evaluated before and after a hailstorm in zones with different degrees of damage. Dual Polarization SAR Vegetation Index and Normalized Pigment Chlorophyll Ratio Index were the most sensitive to hail-induced changes. The time series and rates of change of these indices were used as input variables in the K-means method for clustering pixels into homogeneous damage zones. Validation of the algorithm with data from 91 soybean, wheat, and corn plots showed that in 87.01% of cases there was significant evidence of differences in average damage between zones determined by the algorithm within the plot. Thus, the algorithm presented in this paper allowed efficient detection of homogeneous hail damage zones, which is expected to improve accuracy and transparency in the characterization of hailstorm events. Full article
(This article belongs to the Special Issue Geoinformatics Application in Agriculture)
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Article
Estimation of Daily Reference Evapotranspiration from NASA POWER Reanalysis Products in a Hot Summer Mediterranean Climate
Agronomy 2021, 11(10), 2077; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102077 - 18 Oct 2021
Cited by 1 | Viewed by 456
Abstract
This study aims at assessing the accuracy of estimating daily reference evapotranspiration (ETo) computed with NASA POWER reanalysis products. Daily ETo estimated from local observations of weather variables in 14 weather stations distributed across Alentejo Region, Southern Portugal were compared with ETo derived [...] Read more.
This study aims at assessing the accuracy of estimating daily reference evapotranspiration (ETo) computed with NASA POWER reanalysis products. Daily ETo estimated from local observations of weather variables in 14 weather stations distributed across Alentejo Region, Southern Portugal were compared with ETo derived from NASA POWER weather data, using raw and bias-corrected datasets. Three different methods were used to compute ETo: (a) FAO Penman-Monteith (PM); (b) Hargreaves-Samani (HS); and (c) MaxTET. Results show that, when using raw NASA POWER datasets, a good accuracy between the observed ETo and reanalysis ETo was observed in most locations (R2 > 0.70). PM shows a tendency to over-estimating ETo with an RMSE as high as 1.41 mm d−1, while using a temperature-based ET estimation method, an RMSE lower than 0.92 mm d−1 is obtained. If a local bias correction is adopted, the temperature-based methods show a small over or underestimation of ETo (–0.40 mm d−1 ≤ MBE < 0.40 mm d−1). As for PM, ETo is still underestimated for 13 locations (MBE < 0 mm d−1) but with an RMSE never higher than 0.77 mm d−1. When NASA POWER raw data is used to estimate ETo, HS_Rs proved the most accurate method, providing the lowest RMSE for half the locations. However, if a data regional bias correction is used, PM leads to the most accurate ETo estimation for half the locations; also, when a local bias correction is performed, PM proved the be the most accurate ETo estimation method for most locations. Nonetheless, MaxTET proved to be an accurate method; its simplicity may prove to be successful not only when only maximum temperature data is available but also due to the low data required for ETo estimation. Full article
(This article belongs to the Special Issue Advances in Irrigation Technology and Adaptation to Climate Change)
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Article
Defensive Impact of Foliar Applied Potassium Nitrate on Growth Linked with Improved Physiological and Antioxidative Activities in Sunflower (Helianthus annuus L.) Hybrids Grown under Salinity Stress
Agronomy 2021, 11(10), 2076; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102076 - 17 Oct 2021
Viewed by 377
Abstract
Salt stress is recognized to negatively influence the fundamental processes in plants regarding growth and yield. The sunflower (Helianthus annuus L.) is considered an important industrial crop because of the good quality of oil it produces that can be used for cooking [...] Read more.
Salt stress is recognized to negatively influence the fundamental processes in plants regarding growth and yield. The sunflower (Helianthus annuus L.) is considered an important industrial crop because of the good quality of oil it produces that can be used for cooking purposes. The exogenous application of potassium (K) has been reported to enhance abiotic resistance and increase yield in crops. Here, we explored the impact of foliar-applied K at 500 ppm on the physiological and biochemical traits, antioxidant activities, and growth attributes of sunflower grown under salt stress (140 mM NaCl). The findings indicated that salinity stress adversely affected photosynthesis and various gas exchange characteristics. Foliar applied K markedly improved the stomatal conductance, transpiration rate, water use efficiency, CO2 assimilation rate, total soluble proteins, chlorophyll pigments, and upregulated antioxidant system, which are responsible for the healthy growth of sunflower hybrids grown under salinity stress. The shoot and root lengths, plant fresh and dry weights, and achene weight were significantly increased by K application. Overall, foliar applied K significantly improved all of the aforementioned attributes and can attenuate the deleterious influences of salinity stress in sunflower. Full article
(This article belongs to the Special Issue Improving Mineral Nutrition to Obtain Stress Tolerant Crops)
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Article
Differential Interferometry over Sentinel-1 TopSAR Images as a Tool for Water and Tillage Soil Erosion Analysis
Agronomy 2021, 11(10), 2075; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102075 - 17 Oct 2021
Viewed by 440
Abstract
Erosion is a major problem on agricultural lands in Europe. Erosion measurement tools have traditionally been focused on delocalized quantification but without mapping the real places inside the basin where the erosion took effect. In this article, we use new space missions, such [...] Read more.
Erosion is a major problem on agricultural lands in Europe. Erosion measurement tools have traditionally been focused on delocalized quantification but without mapping the real places inside the basin where the erosion took effect. In this article, we use new space missions, such as Sentinel-1, and the opportunity they offer to obtain SAR (Synthetic Aperture Radar) images with high frequency, resolution, range, and, above all, availability to enable the application of techniques, like differential interferometry, in new fields. We propose to measure ground deformation caused by water and tillage erosion in small agricultural basins using TopSAR (Terrain Observation with Progressive Scans SAR, Synthetic Aperture Radar) images acquired by the Sentinel-1 mission, after previously verifying the accuracy of these measurements through comparison with measurements from a LIDAR (Light Detection and Ranging) system. The results of this work confirm the potential of monitoring erosion in agricultural basins with differential interferometry over Sentinel-1 TopSAR images. Its capabilities have been successfully tested in different conditions related to agricultural tasks without precipitation or storm events. This technique makes it possible to study both water and tillage erosion and sedimentation processes and even to test the efficiency of anti-erosion measures in the field or to verify the results of different management practices over time. Full article
(This article belongs to the Section Agricultural Engineering)
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Review
Recent Trends in the Foliar Spraying of Zinc Nutrient and Zinc Oxide Nanoparticles in Tomato Production
Agronomy 2021, 11(10), 2074; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102074 - 16 Oct 2021
Viewed by 665
Abstract
Growing vegetables can be seen as a means of improving people’s livelihoods and nutritional status. Tomatoes are one of the world’s most commonly planted vegetable crops. The nutritional arrangement of the tomato depends on the quantity and type of nutrients taken from the [...] Read more.
Growing vegetables can be seen as a means of improving people’s livelihoods and nutritional status. Tomatoes are one of the world’s most commonly planted vegetable crops. The nutritional arrangement of the tomato depends on the quantity and type of nutrients taken from the growing medium, such assoil and foliar application; therefore, an adequate amount of macro- and micro-nutrients, including zinc (Zn) and zinc oxide nanoparticles (ZnO-NPs), are crucial for tomato production. Zinc foliar spraying is one of the effective procedures that may improve crop quality and yield. Zinc oxide nanoparticles (ZnO-NPs) are represented as a biosafety concern for biological materials. Foliar application of Zn showed better results in increasing soluble solids(TSS), firmness, titratable acidity, chlorophyll-a, chlorophyll-b, ascorbic acid, amount of lycopene. Researchers have observed the effect of nanoparticles of zinc oxide on various crops, including tomatoes. Foliar spraying of ZnO-NPs gave the most influential results in terms of best planting parameters, namely plant height, early flowering, fruit yields as well as lycopene content. Therefore, more attention should be given to improving quantity and quality as well as nutrient use efficiency of Zn and ZnO-NPs in tomato production. Recent information on the effect of zinc nutrient foliar spraying and ZnO-NPs as a nano fertilizer on tomato productivity is reviewed in this article. Full article
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Article
Agronomic and Environmental Performances of On-Farm Compost Production and Application in an Organic Vegetable Rotation
Agronomy 2021, 11(10), 2073; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102073 - 16 Oct 2021
Viewed by 454
Abstract
Horticultural crops produce huge amounts of wastes due to the large difference between total and marketable yields, and plant residues. The biological stabilization and sanitization of these organic materials directly on-farm through a simple technique such as composting may be a feasible and [...] Read more.
Horticultural crops produce huge amounts of wastes due to the large difference between total and marketable yields, and plant residues. The biological stabilization and sanitization of these organic materials directly on-farm through a simple technique such as composting may be a feasible and sustainable management strategy. The objectives of this research were to (i) estimate the sustainability and the energy impact of the on-farm composting process; (ii) to evaluate the agronomic performance and sustainability of the compost application, compared to a commercial organic fertilizer; and (iii) to identify the management and environmental hotspots. To accomplish these aims, a composting process was set up and monitored using the organic wastes and residues produced in the experimental farm. The compost produced was compared to a commercial organic fertilizer in combination with the use of cover crops in the rotation, in a two-year pepper cultivation. All processes were assessed using an energy analysis and a carbon stocks and emissions evaluation. Our findings point out that the composting process on-farm was environmentally sustainable in terms of energy consumption and carbon emissions and produced a good quality fertilizer. The use of this compost determined the best agronomic performance, especially when it was combined with other agro-ecological techniques. The yield values were slightly higher and statistically comparable with the commercial fertilizer ones. Moreover, the treatments that included the compost were most energy efficient and showed the best compromise between C emissions and C stocks. Full article
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Article
Predicting the Emergence of Echinochloa crus-galli (L.) P. Beauv. in Maize Crop in Croatia with Hydrothermal Model
Agronomy 2021, 11(10), 2072; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102072 - 15 Oct 2021
Viewed by 267
Abstract
Echinochloa crus-galli (L.) P. Beauv. is the most common monocotyledonous weed in maize crops in Croatia. Crop–weed interference is influenced by weed emergence patterns, and knowledge of the timing of weed emergence is crucial for the development of an efficient integrated weed-management program. [...] Read more.
Echinochloa crus-galli (L.) P. Beauv. is the most common monocotyledonous weed in maize crops in Croatia. Crop–weed interference is influenced by weed emergence patterns, and knowledge of the timing of weed emergence is crucial for the development of an efficient integrated weed-management program. Therefore, two-year field experiments were conducted in a maize crop sown in early May in continental Croatia to determine the emergence pattern of E. crus-galli from natural seedbank. In laboratory studies, the estimated base temperature and base water potential for the Croatian ecotype of E. crus-galli were 10.8 °C and −0.97 MPa, respectively. Then, the estimated germination parameters were compared with the values embedded in the AlertInf model from Italy (Veneto) to calibrate this hydrothermal model. The estimated hydrothermal units were around 28 for the onset (10%) and 93 for the middle (50%) emergence of E. crus-galli. Our findings showed that the AlertInf model satisfactorily simulated the emergence of E. crus-galli in maize crop in Croatia (EF = 0.97 in 2019 and 0.98 in 2020), indicating its potential use in other geographical areas Full article
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Article
Assessing and Modeling Ecosystem Carbon Exchange and Water Vapor Flux of a Pasture Ecosystem in the Temperate Climate-Transition Zone
Agronomy 2021, 11(10), 2071; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102071 - 15 Oct 2021
Viewed by 214
Abstract
The rising frequency of extreme weather events and global warming are greatly challenging pastoral ecosystem productivity, particularly in the temperate climate-transition regions. While this could cause greater gross primary production (GPP) mainly contributed by the warm-season vegetation, the consequences for the dynamics of [...] Read more.
The rising frequency of extreme weather events and global warming are greatly challenging pastoral ecosystem productivity, particularly in the temperate climate-transition regions. While this could cause greater gross primary production (GPP) mainly contributed by the warm-season vegetation, the consequences for the dynamics of net ecosystem exchange (NEE) and hydrological responses (e.g., evapotranspiration, ET) on an ecosystem level are poorly known. Here, we investigated the evolution of plant phenology, nutritive value, energy balance, and carbon/water budgets of a cool-season dominated pastoral ecosystem in the temperate zone; integrating both eddy covariance (EC) flux measurement and simulation modeling-based uncertainty analysis. Throughout the two-year duration (2017–2018) of this study, the entire pasture ecosystem remained a strong carbon sink (NEE = −1.23 and −1.95 kg C m−2, respectively) with 74% and 62% of available energy loss explained by EC fluxes, respectively. The cumulative ET was 735.8 and 796.8 mm, respectively; and the overall ecosystem water use efficiency (EWUE) were calculated as 6.5 g C kg−1 water across both growing seasons. The above-ground biomass yield agreed with the cumulative GPP and was inversely correlated with grass nutritive value. The uncertainty analysis indicated that accurate EC flux gap-filling models could be constructed using support vector machine trained time-series models (NEE, R2 = 0.77, RMSE = 11.8; ET, R2 = 0.90, RMSE = 73.8). The performance benchmarking tests indicated that REddyProc-based gap-filling performance was very limiting and highly variable (NEE, R2 = 0.21–0.64; ET, R2 = 0.79–0.87), particularly for estimating NEE. Overall, the warm-season vegetation encroachment greatly filled the production gap of cool-season grasses, leading to greater cumulative NEE and EWUE on a system level, compared with those from many other reported field-crop or grassland studies using EC approaches. The complex and dynamic nature of grassland ecosystems greatly challenged the conventional REddyProc-based EC flux gap-filling performance. However, accurate machine learning models could be constructed for error/uncertainty control purposes and, thus, should be encouraged in future studies. Full article
(This article belongs to the Section Grassland and Pasture Science)
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Article
Combined Use of Calciprill and Sodium Silicate Improves Chemical Properties of Low-pH Soil
Agronomy 2021, 11(10), 2070; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102070 - 15 Oct 2021
Viewed by 254
Abstract
The highly weathered, acidic tropical soils are generally less fertile because of their low pH, high exchangeable acidity, and Al, Fe, and Mn saturations. Using soil amendments to solve the aforementioned problems is essential. To this end, Calciprill and sodium silicate are worth [...] Read more.
The highly weathered, acidic tropical soils are generally less fertile because of their low pH, high exchangeable acidity, and Al, Fe, and Mn saturations. Using soil amendments to solve the aforementioned problems is essential. To this end, Calciprill and sodium silicate are worth considering because of their high neutralizing value and dissolution to suppress exchangeable acidity and Al, Fe, and Mn hydrolysis, while at the same time increasing soil pH to improve the availability of inorganic N, available P, exchangeable base cations, and Effective Cation Exchange Capacity (ECEC). An incubation study was conducted to determine the right combination of Calciprill and sodium silicate to reduce exchangeable acidity and Al and Fe hydrolysis to improve inorganic N, available P, exchangeable base cations availability, and ECEC. Bekenu series (Typic Paleudults) was incubated with a combined use of Calciprill at 80%, 90%, and 100% Ca saturations and sodium silicate at 90, 105, 120, 135, and 150 kg ha−1 for 40, 80, and 120 days, respectively. The laboratory incubation study was carried out using a Completely Randomized Design (CRD) with triplicates to determine the aforementioned treatment effects of the combined use of Calciprill and sodium silicate on soil pH, exchangeable, Al, inorganic N, available P, electrical conductivity, exchangeable cations (K, Ca, Mg, Na, Fe, and Mn), and ECEC using standard procedures. Soils with both amendments significantly increased soil inorganic N, available P, electrical conductivity, exchangeable base cations (K, Ca, Mg, and Na), and ECEC. This was because the amendments increased soil pH by suppressing exchangeable acidity. Moreover, they transformed Al, Fe, and Mn ions into insoluble compounds such as Al and Fe hydroxides and Mn oxides because of their high inherent exchangeable cations, especially Ca and Na. This suggests that the combined use of Calciprill and sodium silicate can enhance soil productivity. The most suitable combination is 7.80 g Calciprill and 9.26 g sodium silicate (C3S5) per one kilogram soil. Additionally, the findings provide fundamental information for future greenhouse and field trials to determine the effects of the suitable combination of the amendments uncovered by this present study on soil health and crop productivity. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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Article
Long-Term Fertilization and Lime-Induced Soil pH Changes Affect Nitrogen Use Efficiency and Grain Yields in Acidic Soil under Wheat-Maize Rotation
Agronomy 2021, 11(10), 2069; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102069 - 15 Oct 2021
Viewed by 505
Abstract
Liming (L) is a common practice to mitigate soil acidification and enhance soil quality and crop productivity. However, in acidic soil, it is not clear how long-term application of lime and nitrogen (N)-based fertilizer affects soil chemical properties, the wheat and maize grain [...] Read more.
Liming (L) is a common practice to mitigate soil acidification and enhance soil quality and crop productivity. However, in acidic soil, it is not clear how long-term application of lime and nitrogen (N)-based fertilizer affects soil chemical properties, the wheat and maize grain yields (GY), and N-use efficiency (NUE). Thus, to investigate the effects of N-based fertilizations without L (−L) and with L (+L) on wheat and maize GY and NUE through their effects on soil chemical properties, we analyzed a 28-year field experiment in acidic soil under a wheat-maize system in South China. The analysis was carried out between 1991 and 2010 (before L) and between 2011 and 2018 (after L). We categorized the treatments into (1) no fertilizer (C); nitrogen (N); N and phosphorus (NP); N and potassium (NK); N, P and K (NPK); and NPKCR, NPK and crops residue (CR) applications (NPKCR), before L; and (2) C; N−L; N+L; NP−L; NP+L; NK−L; NK+L; NPK−L; NPK+L; NPKCR−L and NPKCR+L, after L. The effects of long-term fertilization resulted in lower soil pH by 15%, soil available K (AK) by 19%, POlsen by 6%, NO3-N by 15%, soil organic matter (SOM) by 16%, total N by 16%, and C:N ratio by 13% in −L soil than in +L soil. However, the accumulation of NH4+-N was higher by 40% in −L soil than in +L soil. Wheat and maize GY, N recovery efficiency (REN), and N partial factor productivity (PEPN) were more adversely affected by 8-year fertilizations in −L compared with fertilizations before L and in +L primarily because of the significantly decreased soil pH. Conversely, improvements in wheat and maize yields, REN, and PFPN by 8-year fertilizations in +L were related to increasing soil pH, exchangeable base cations such as Ca2+, Mg2+, and the alleviated toxicity of Al3+. Overall, improvement of GY and NUE from the acidified soil in South China requires the long-term integrated use of fertilizer (NPK), retention of CR, and the +L (i.e., NPKCR+L). Full article
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Article
Exploration of Machine Learning Approaches for Paddy Yield Prediction in Eastern Part of Tamilnadu
Agronomy 2021, 11(10), 2068; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102068 - 15 Oct 2021
Viewed by 288
Abstract
Agriculture is the principal basis of livelihood that acts as a mainstay of any country. There are several changes faced by the farmers due to various factors such as water shortage, undefined price owing to demand–supply, weather uncertainties, and inaccurate crop prediction. The [...] Read more.
Agriculture is the principal basis of livelihood that acts as a mainstay of any country. There are several changes faced by the farmers due to various factors such as water shortage, undefined price owing to demand–supply, weather uncertainties, and inaccurate crop prediction. The prediction of crop yield, notably paddy yield, is an intricate assignment owing to its dependency on several factors such as crop genotype, environmental factors, management practices, and their interactions. Researchers are used to predicting the paddy yield using statistical approaches, but they failed to attain higher accuracy due to several factors. Therefore, machine learning methods such as support vector regression (SVR), general regression neural networks (GRNNs), radial basis functional neural networks (RBFNNs), and back-propagation neural networks (BPNNs) are demonstrated to predict the paddy yield accurately for the Cauvery Delta Zone (CDZ), which lies in the eastern part of Tamil Nadu, South India. The performance of each developed model is examined using assessment metrics such as coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), mean squared error (MSE), mean absolute percentage error (MAPE), coefficient of variance (CV), and normalized mean squared error (NMSE). The observed results show that the GRNN algorithm delivers superior evaluation metrics such as R2, RMSE, MAE, MSE, MAPE, CV, and NSME values about 0.9863, 0.2295 and 0.1290, 0.0526, 1.3439, 0.0255, and 0.0136, respectively, which ensures accurate crop yield prediction compared with other methods. Finally, the performance of the GRNN model is compared with other available models from several studies in the literature, and it is found to be high while comparing the prediction accuracy using evaluation metrics. Full article
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Article
Assessing a Removable Mini-Lysimeter for Monitoring Crop Evapotranspiration Using a Well-Established Large Weighing Lysimeter: A Case Study for Barley and Potato
Agronomy 2021, 11(10), 2067; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102067 - 15 Oct 2021
Viewed by 377
Abstract
Further research is required on the measurement of crop evapotranspiration (ETc) to produce new or updated crop coefficients for a large number of crops using accurate weighing lysimeters. However, large weighing lysimeters are sometimes expensive and are not portable, and different [...] Read more.
Further research is required on the measurement of crop evapotranspiration (ETc) to produce new or updated crop coefficients for a large number of crops using accurate weighing lysimeters. However, large weighing lysimeters are sometimes expensive and are not portable, and different prototypes of small-sized lysimeters may be a feasible alternative. This study evaluated the performance of a removable mini-lysimeter model to measure ETc and derive crop coefficients using a long-established large precision weighing lysimeter over a two-year period. The study was conducted during the 2017 and 2018 barley and potato growing seasons, respectively, at a lysimeter facility located in Albacete (southeast Spain). ETc values were determined using daily mass change in the lysimeters. Irrigation was managed to avoid any water stress. In the barley season, the mini-lysimeter underestimated the seasonal ETc by 2%, the resulting errors in barley ETc estimation were an MBE of −0.070 mm d−1 and an RMSE of ±0.289 mm d−1. In the potato season, the mini-lysimeter overestimated the cumulative ETc by 5%, the resulting errors in potato ETc measurement were an MBE of 0.222 mm d−1 and an RMSE of ±0.497 mm d−1. The goodness of fit indicators showed a good agreement between the large and mini-lysimeter barley and potato ETc measurements at daily time step. Single (Kc) and dual crop coefficients (Kcb, crop transpiration + Ke, soil evaporation) were derived from the lysimeter measurements, the grass reference evapotranspiration (ETo) and the FAO56 dual Kc approach; after temperate standard climate adjustment, mid-season values were Kc mid (std) = 1.05 and Kcb mid (std) = 1.00 for barley; and Kc mid (std) = 1.06 and Kcb mid (std) = 1.02 for potato. The good agreement found between Kcb values and fc will allow barley and potato water requirements to be accurately estimated. Full article
(This article belongs to the Special Issue Modernization and Optimization of Irrigation Systems)
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Article
Gliding Arc Plasma Treatment of Maize (Zea mays L.) Grains Promotes Seed Germination and Early Growth, Affecting Hormone Pools, but Not Significantly Photosynthetic Parameters
Agronomy 2021, 11(10), 2066; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102066 - 14 Oct 2021
Viewed by 319
Abstract
Maize grains (Zea mays convar. Indentata Sturt.) were treated with non-thermal plasma, where Gliding Arc plasma discharge at an atmospheric pressure was used (working gas: Air; time duration: 0 s, 180 s, 300 s, 600 s). The experiment was conducted at a [...] Read more.
Maize grains (Zea mays convar. Indentata Sturt.) were treated with non-thermal plasma, where Gliding Arc plasma discharge at an atmospheric pressure was used (working gas: Air; time duration: 0 s, 180 s, 300 s, 600 s). The experiment was conducted at a temperature of 18 °C, light/dark 12/12 h, and a light intensity of 100 µmol/m2s. Seed germination, seedling growth, photosynthetic parameters, and hormone (abscisic acid, jasmonic acid, salicylic acid, indole-3-acetic acid, and cytokinin) contents were measured. The highest stimulation of seed germination (to 141%), root length (to 221%), shoot length (to 298%), and root weight (to 122%) in comparison with the control was recorded after Gliding Arc plasma treatment for 600 s. The photochemical and non-photochemical Chl fluorescence parameters were not significantly affected by Gliding Arc plasma treatment. In contrast, hormonal pools in maize were significantly affected. The short-term plasma treatment (180 s) was associated with a decrease in the stress hormones abscisic acid, salicylic acid, jasmonic acid, and jasmonate isoleucine, while indole-3-acetic acid and cytokinin precursors were elevated. Longer-term treatment (300 s, 600 s) had an opposite effect—an elevation of abscisic acid, jasmonic acid, and jasmonate isoleucine as well as active cytokinins. The content of auxin decreased. Gliding plasma treatment may significantly affect maize physiology, dependent on the treatment duration. Full article
(This article belongs to the Special Issue Applied High-Voltage Plasma Technologies in Agricultural Industry)
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Article
Comparative Effects of Bio-Wastes in Combination with Plant Growth-Promoting Bacteria on Growth and Productivity of Okra
Agronomy 2021, 11(10), 2065; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102065 - 14 Oct 2021
Viewed by 370
Abstract
Plant growth-promoting rhizobacteria with multiple growth-promoting traits play a significant role in soil to improve soil health, crop growth and yield. Recent research studies have focused on the integration of organic amendments with plant growth-promoting rhizobacteria (PGPR) to enhance soil fertility and reduce [...] Read more.
Plant growth-promoting rhizobacteria with multiple growth-promoting traits play a significant role in soil to improve soil health, crop growth and yield. Recent research studies have focused on the integration of organic amendments with plant growth-promoting rhizobacteria (PGPR) to enhance soil fertility and reduce the hazardous effects of chemical fertilizers. This study aims to evaluate the integrated application of biochar, compost, fruit and vegetable waste, and Bacillus subtilis (SMBL 1) to soil in sole application and in combined form. The study comprises eight treatments—four treatments without inoculation and four treatments with SMBL 1 inoculation in a completely randomized design (CRD), under factorial settings with four replications. The results indicate that the integrated treatments significantly improved okra growth and yield compared with sole applications. The integration of SMBL 1 with biochar showed significant improvements in plant height, root length, leaf chlorophyll a and b, leaf relative water content, fruit weight, diameter and length by 29, 29, 50, 53.3, 4.3, 44.7 and 40.4%, respectively, compared with control. Similarly, fruit N, P and K contents were improved by 33, 52.7 and 25.6% and Fe and Zn in shoot were 37.1 and 35.6%, respectively, compared with control. The results of this study reveal that the integration of SMBL 1 with organic amendments is an effective approach to the sustainable production of okra. Full article
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Article
Testing Combined Effect of Amendments and Inoculation with Bacteria for Improving Phytostabilisation of Smelter Waste Extremely Contaminated with Trace Elements
Agronomy 2021, 11(10), 2064; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102064 - 14 Oct 2021
Viewed by 289
Abstract
Smelter waste deposits pose environmental and health threats and require remediation actions. Phytostabilisation techniques, based on soil amendments, help to establish plant cover and limit the secondary emission of potentially toxic trace elements. However, methods to optimize their effectiveness are needed. The application [...] Read more.
Smelter waste deposits pose environmental and health threats and require remediation actions. Phytostabilisation techniques, based on soil amendments, help to establish plant cover and limit the secondary emission of potentially toxic trace elements. However, methods to optimize their effectiveness are needed. The application of bacterial inoculants in combination with soil amendments in the remediation of soils and wastes contaminated with metals still has not been extensively tested. Therefore, the aim of this study was to determine the effectiveness of indigenous (Streptomyces sp., Pseudomonas sp.) and foreign (Streptomyces costaricanus) strains of bacteria in supporting grass growth on extremely contaminated waste slag. They were applied alone and in combination with compost mixed with phosphate fertilizer or iron oxide. The tested strains improved plant growth and increased plant availability of phosphorus. The interaction of the soil amendments and some bacterial strains also stimulated a decrease in the extractability of metals, likely through the phosphate-induced precipitation of lead. Our data show that the effectiveness of soil amendments in the phytostabilisation of heavily polluted smelter deposits can be enhanced by plant growth-promoting bacteria (PGPB). Full article
(This article belongs to the Special Issue New Phytoremediation in Trace Elements Contaminated Soils)
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Article
The Role of Water Content in the Casing Layer for Mushroom Crop Production and the Occurrence of Fungal Diseases
Agronomy 2021, 11(10), 2063; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102063 - 14 Oct 2021
Viewed by 282
Abstract
Mushroom cultivation requires effective control of environmental cues to obtain the best yield and high quality. The impact of water content in the casing layer on mushroom yield and the incidence of two of the most important diseases in the mushroom growing farms, [...] Read more.
Mushroom cultivation requires effective control of environmental cues to obtain the best yield and high quality. The impact of water content in the casing layer on mushroom yield and the incidence of two of the most important diseases in the mushroom growing farms, dry bubble and cobweb diseases, was evaluated. Different initial water content in the casing and two alternative irrigation programs applied (light or moderate irrigation) were the agronomic parameters under study during five separate button mushroom crop trials. Higher initial humidity content in the casing layer reported a larger yield, with a fewer number of basidiomes but heavier, while no correlation to the dry matter content or the colour of the basidiomes was noted. The incidence of dry bubble disease was not conditioned by the water content of the casing layer, at the high moisture levels established in the study. In the case of Cladobotryum mycophilum, the lower moisture level of the casing layer reported more incidence of cobweb disease, and subsequently harmful yield losses. According to the results obtained, the right management of the moisture level in the casing materials could promote crop yield and preclude the significant impact of dry bubble and cobweb diseases. Full article
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Article
Dual Crop Coefficient Approach in Vitis vinifera L. cv. Loureiro
Agronomy 2021, 11(10), 2062; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102062 - 14 Oct 2021
Viewed by 509
Abstract
Vineyard irrigation management in temperate zones requires knowledge of the crop water requirements, especially in the context of climate change. The main objective of this work was to estimate the crop evapotranspiration (ETc) of Vitis vinifera cv. Loureiro for local conditions, [...] Read more.
Vineyard irrigation management in temperate zones requires knowledge of the crop water requirements, especially in the context of climate change. The main objective of this work was to estimate the crop evapotranspiration (ETc) of Vitis vinifera cv. Loureiro for local conditions, applying the dual crop coefficient approach. The study was carried out in a vineyard during two growing seasons (2019–2020). Three irrigation treatments, full irrigation (FI), deficit irrigation (DI), and rainfed (R), were considered. The ETc was estimated using the SIMDualKc model, which performs the soil water balance with the dual Kc approach. This balance was performed by calculating the basal coefficients for the grapevine (Kcb crop) and the active soil ground cover (Kcb gcover), which represent the transpiration component of ETc and the soil evaporation coefficient (Ke). The model was calibrated and validated by comparing the simulated soil water content (SWC) with the soil water content data measured with frequency domain reflectometry (FDR). A suitable adjustment between the simulated and observed SWC was obtained for the 2019 R strategy when the model was calibrated. As for the vine crop, the best fit was obtained for Kcb full ini = 0.33, Kcb full mid = 0.684, and Kcb full end = 0.54. In this sense, the irrigation schedule must adjust these coefficients to local conditions to achieve economically and environmentally sustainable production. Full article
(This article belongs to the Special Issue Papers from AgEng2021)
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