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Agronomy, Volume 13, Issue 12 (December 2023) – 232 articles

Cover Story (view full-size image): The quality of forages declines as plants reach the flowering stage. Therefore, accelerating flowering may increase forage quality and the number of harvests. Healthy soils are rich in vitamin B12 and humic substances. Research has revealed that biochar promotes root systems and photosynthesis rates, thus enhancing overall plant productivity. The current study hypothesized that the presence of adequate vitamin B12, humic substances, and biochar can positively alter the phenology, nitrogen yield, and biomass of clover roots and shoots. View this paper
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18 pages, 4293 KiB  
Article
CO2 Emissions from Soils under Different Tillage Practices and Weather Conditions
Agronomy 2023, 13(12), 3084; https://doi.org/10.3390/agronomy13123084 - 18 Dec 2023
Viewed by 721
Abstract
CO2 emissions are one of the greenhouse gases that significantly contribute to climate change. The use of reduced soil tillage practices could contribute to the mitigation of CO2 emissions from soils under ongoing climate change conditions. The use of reduced and [...] Read more.
CO2 emissions are one of the greenhouse gases that significantly contribute to climate change. The use of reduced soil tillage practices could contribute to the mitigation of CO2 emissions from soils under ongoing climate change conditions. The use of reduced and no-tillage practices in the summer period, the most critical period for CO2 and for water loss from soils, would contribute to the mitigation of CO2 emissions that is required by the European Union. The aim of this research was to contribute to the specification of CO2 emission factors, following different soil tillage practices in the summer period under variations in weather. Gentler tillage practices were defined in terms of reducing CO2 emissions from the soil. This research was carried out as a long-term field experiment. The effects of soil tillage practices on CO2 emissions were studied over a six-year period as a long-term field experiment and concerned the use of different soil tillage practices for over 20 years (established in 1995), with these including conventional tillage (CT; plowing to 20–22 cm), reduced tillage (RT; chiseling to 10 cm), and no-tillage (NT; without tillage). The crop rotation was winter wheat–winter oilseed rape–winter wheat–pea. CO2 emissions were measured at least 7–10 times during the summer–autumn period in the years 2017–2022 after agrotechnical operations following the winter wheat harvest. Soil moisture was determined in all the treatments. Weather conditions were measured by means of the meteorological station of the Crop Research Institute. The CO2 emissions were the highest in the summer period under CT in comparison with RT and NT. Reduced tillage and no-tillage practices, with mulch on the surface of the soil, decreased CO2 emissions by a 6-year average of 45% and 51%, respectively. The mean CO2 emissions were 6.1, 3.1, and 2.9 μmol CO2 m−2 s−1 for CT, RT, and NT. The highest CO2 emissions and the largest differences among different tillage practices were measured in 2019, with high temperatures and repeated rainfall. CO2 emissions under CT reached 22 μmol CO2 m−2 s−1, which was 7.5 and 5.8 times higher than under RT and NT, respectively. Current weather conditions, mainly temperature and precipitation, played an important role in CO2 emissions. The hot and dry weather in 2018 decreased overall CO2 emissions, with CO2 emissions, even under conventional tillage, reaching only 2.5 μmol CO2 m−2 s−1 on average. As a result of climate change, the temperatures also gradually increased in the later stages of the year, with more summer days being expected during autumn and higher CO2 emissions from soils being expected as a result. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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17 pages, 1269 KiB  
Article
Efficacy of Eco-Friendly Bio-Pesticides against the Whitefly Bemisia tabaci (Gennadius) for Sustainable Eggplant Cultivation in Kebbi State, Nigeria
Agronomy 2023, 13(12), 3083; https://doi.org/10.3390/agronomy13123083 - 18 Dec 2023
Viewed by 935
Abstract
The eggplant (Solanum melongena L.) is among the vital fruit vegetables cultivated globally for its health and nutritional benefits. However, its production has been hindered by whiteflies (Bemisia tabaci G.) infestation worldwide. This study aims to assess the effect of some [...] Read more.
The eggplant (Solanum melongena L.) is among the vital fruit vegetables cultivated globally for its health and nutritional benefits. However, its production has been hindered by whiteflies (Bemisia tabaci G.) infestation worldwide. This study aims to assess the effect of some bio-pesticides in the control of whiteflies on eggplants under field conditions. The trial consists of seventeen (17) treatments replicated three times for 45 days. From the results obtained, neem leaf extract (60 mL/L) proved more effective against whiteflies, with 1.2 and 1.3 adults/leaf, while buttermilk and cow dung (50 mL/L) were less effective (10.1 and 10.8 adults/leaf) when compared to untreated plots (26.9 and 33.4 adults/leaf), two weeks after the third spray during the first and second trials. The highest reduction (%) in whitefly population was found using neem leaf extract (95.7 and 96.1%) and cow urine (85.8 and 96.1%), with cow dung and buttermilk exhibiting the least overall averages (65.9 and 62.3%), two weeks after the third spray during the respective trials. Neem extract and cow urine were more effective among the treatments examined and, thus, recommended to be incorporated into control strategies of whiteflies for the improved production of eggplants in the area. Full article
(This article belongs to the Section Pest and Disease Management)
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15 pages, 2007 KiB  
Article
Estimation of Evapotranspiration from the People’s Victory Irrigation District Based on the Data Mining Sharpener Model
Agronomy 2023, 13(12), 3082; https://doi.org/10.3390/agronomy13123082 - 18 Dec 2023
Viewed by 723
Abstract
Reasonable evaluation of evapotranspiration (ET) is crucial for optimizing agricultural water resource management. In the study, we utilized the Data Mining Sharpener (DMS) model; the Landsat thermal infrared images were sharpened from a spatial resolution of 100 m to 30 m. We then [...] Read more.
Reasonable evaluation of evapotranspiration (ET) is crucial for optimizing agricultural water resource management. In the study, we utilized the Data Mining Sharpener (DMS) model; the Landsat thermal infrared images were sharpened from a spatial resolution of 100 m to 30 m. We then used the Surface Energy Balance System (SEBS) to estimate daily ET during the winter wheat growing season in the People’s Victory Irrigation District in Henan, China. It was concluded that the spatiotemporal patterns of land surface temperature and daily evapotranspiration remained consistent before and after sharpening. Results showed that the R2 value between the ET of 30 m spatial resolution and the value by eddy covariance method reached 0.814, with an RMSE of 0.516 mm and an MAE of 0.245 mm. All of these were higher than those of 100 m spatial resolution (R2 was 0.802, the RMSE was 0.534 mm, and the MAE was 0.253 mm). Furthermore, the daily ET image with a 30 m spatial resolution exhibited clear texture and distinct boundaries, without any noticeable mosaic effects. The changes in surface temperature and ET were more consistent in complex subsurface environments. The daily evapotranspiration of winter wheat was significantly higher in areas with intricate drainage systems compared to other regions. During the early growth stage, daily evapotranspiration decreased steadily until the overwintering stage. After the greening and jointing stages, it began to increase and peaked during the sizing period. The correlation between net solar radiation and temperature with ET was significant, while relative humidity and soil moisture were negatively correlated with ET. Throughout the growth period, net solar radiation had the greatest effect on ET. Full article
(This article belongs to the Section Water Use and Irrigation)
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20 pages, 24635 KiB  
Article
Optimizing Nitrogen Management for Summer Maize in the Yellow River Basin a Water Heat Carbon and N Simulator Model Approach with Entropy-Weighted Technique for Order Preference by Similarity to Ideal Solution Analysis
Agronomy 2023, 13(12), 3081; https://doi.org/10.3390/agronomy13123081 - 18 Dec 2023
Viewed by 496
Abstract
Summer maize constitutes a major food crop in the Yellow River Basin. Optimizing nitrogen (N) application management for this crop not only elevates its yield but also reduces N leaching, thereby ensuring food security and lessening agricultural surface pollution. Utilizing two years of [...] Read more.
Summer maize constitutes a major food crop in the Yellow River Basin. Optimizing nitrogen (N) application management for this crop not only elevates its yield but also reduces N leaching, thereby ensuring food security and lessening agricultural surface pollution. Utilizing two years of summer maize field experiments, the soil water heat carbon and N simulator (WHCNS) was calibrated and validated against empirical measurements. Subsequent analyses employed the calibrated WHCNS to analyze 56 different N management scenarios. These scenarios varied in terms of N application levels, basal N to topdress application ratios, and chase ratios. The entropy-weighted TOPSIS method was utilized for the optimization, considering agronomic, environmental, and economic aspects. The model’s calibration accuracy was validated by root mean square errors, relative root mean square errors, and mean errors for soil volumetric water content and soil nitrate N content. The calibration results demonstrated that the new model was capable of simulating the soil hydraulic characteristics, N cycling, and the growth and development of summer maize during the reproductive phase in the Yellow River Basin. Scenario analyses revealed that increasing the N application initially elevated, then stabilized, summer maize yields, whereas the N agronomic efficiency first increased and then decreased. Moreover, reducing the basal N to topdress application ratios and increasing the chase ratios during the tasseling and flowering stages could minimize the nitrate N leaching and optimize both the yield and N fertilizer agronomic utilization. Specifically, the optimal N management for the current year involved applying 170 kg·ha−1 of N with a basal N to the topdress N application ratio of 1:5 and a chase ratio of 1:1 during the tasseling and flowering stages. This study lays the foundation for developing N fertilizer management strategies for summer maize cultivation in the Yellow River Basin. Furthermore, the methodology established here can be adapted for optimizing the management of diverse crops in different geographical regions. Full article
(This article belongs to the Section Agroecology Innovation: Achieving System Resilience)
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15 pages, 5460 KiB  
Article
RGB-D Heterogeneous Image Feature Fusion for YOLOfuse Apple Detection Model
Agronomy 2023, 13(12), 3080; https://doi.org/10.3390/agronomy13123080 - 18 Dec 2023
Viewed by 583
Abstract
Heterogeneous image features are complementary, and feature fusion of heterogeneous images can increase position effectiveness of occluded apple targets. A YOLOfuse apple detection model based on RGB-D heterogeneous image feature fusion is proposed. Combining the CSPDarknet53-Tiny network on the basis of a YOLOv5s [...] Read more.
Heterogeneous image features are complementary, and feature fusion of heterogeneous images can increase position effectiveness of occluded apple targets. A YOLOfuse apple detection model based on RGB-D heterogeneous image feature fusion is proposed. Combining the CSPDarknet53-Tiny network on the basis of a YOLOv5s backbone network, a two-branch feature extraction network is formed for the extraction task of RGB-D heterogeneous images. The two-branch backbone network is fused to maximize the retention of useful features and reduce the computational effort. A coordinate attention (CA) module is embedded into the backbone network. The Soft-NMS algorithm is introduced, instead of the general NMS algorithm, to reduce the false suppression phenomenon of the algorithm on dense objects and reduce the missed position rate of obscured apples. It indicates that the YOLOfuse model has an AP value of 94.2% and a detection frame rate of 51.761 FPS. Comparing with the YOLOv5 s, m, l, and x4 versions as well as the YOLOv3, YOLOv4, YOLOv4-Tiny, and Faster RCNN on the test set, the results show that the AP value of the proposed model is 0.8, 2.4, 2.5, 2.3, and 2.2 percentage points higher than that of YOLOv5s, YOLOv3, YOLOv4, YOLOv4-Tiny, and Faster RCNN, respectively. Compared with YOLOv5m, YOLOv5l, and YOLOv5x, the speedups of 9.934FPS, 18.45FPS, and 23.159FPS are obtained in the detection frame rate, respectively, and the model are better in both of parameter’s number and model size. The YOLOfuse model can effectively fuse RGB-D heterogeneous source image features to efficiently identify apple objects in a natural orchard environment and provide technical support for the vision system of picking robots. Full article
(This article belongs to the Section Precision and Digital Agriculture)
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16 pages, 14114 KiB  
Article
Evaluating Effects of Nitrogen and Phosphorus Discharges under Different Reduction Scenarios: A Case of Chaohu Lake Basin, China
Agronomy 2023, 13(12), 3079; https://doi.org/10.3390/agronomy13123079 - 18 Dec 2023
Viewed by 727
Abstract
Determining the amount of nitrogen (N) and phosphorus (P) discharged into lakes and assessing the effectiveness of reduction measures in a basin that involve the interaction of multiple factors are still daunting challenges. In this study, the random forest (RF) model was employed [...] Read more.
Determining the amount of nitrogen (N) and phosphorus (P) discharged into lakes and assessing the effectiveness of reduction measures in a basin that involve the interaction of multiple factors are still daunting challenges. In this study, the random forest (RF) model was employed to simulate the impact of controlling measures on the amount of N and P discharged in 2025 under seven specific reduction scenarios. Discharged N and P decreased in the basin by 23.38% and 31.69% from 2011 to 2020, respectively. The N and P nutrient discharge intensities were significantly higher in the western part of the basin (13.31 kg·ha−1·a−1 and 1.34 kg·ha−1·a−1) than those in the eastern region (10.24 kg·ha−1·a−1 and 0.74 kg·ha−1·a−1). Fertilizer runoff (N: 34.72%, 5934.49 t; P: 13.60%, 199.76 t), domestic sewage (N: 29.14%, 4009.27 t; P: 34.84%, 496.59 t), and livestock farming (N: 15.11%, 2657.50 t; P: 40.05%, 616.05 t) were the key sources of N and P. The RF model shows that (R2 > 0.994, p < 0.01) the multi-factor reduction effect is the best, and under this discharge reduction effect, the amount of N and P discharged in 2025 are expected to decrease by 13.79% and 19.42%, respectively, compared with those in 2020. In addition, different key sources in sub-basins might lead to regional differences in the discharge reduction effects of various measures. Ultimately, we recommend that the synergistic treatment of point and non-point sources, using treatments with multiple measures, should be implemented in different regions to reduce the amount of N and P discharged in the Chaohu Lake Basin. Full article
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21 pages, 10769 KiB  
Article
Exogenous GR24 Inhibits Strawberry Tillering by Affecting the Phytohormone Signaling and Sugar Metabolism Pathways
Agronomy 2023, 13(12), 3078; https://doi.org/10.3390/agronomy13123078 - 17 Dec 2023
Viewed by 758
Abstract
Tillering is an important part in strawberry growth, and strawberries can reproduce nutritionally through stolons to generate genetically stable offspring. However, excessive tillering during the fruit-growing stage can negatively impact fruit yield and quality. In this study, different concentrations of exogenous rac-GR24 (GR24) [...] Read more.
Tillering is an important part in strawberry growth, and strawberries can reproduce nutritionally through stolons to generate genetically stable offspring. However, excessive tillering during the fruit-growing stage can negatively impact fruit yield and quality. In this study, different concentrations of exogenous rac-GR24 (GR24) are used to treat the strawberry plants. It was found that GR24 effectively inhibited the sprouting of strawberry stolons, while promoting the growth of the stems and leaves. Among the treatments, the most effective concentration was found to be 5 μmol/L GR24. This treatment resulted in a decrease in the glucose content in the strawberry crowns and also caused changes in the contents of two endogenous phytohormones, gibberellic acid (GA3) and trans-zeatin riboside (tZR). Transcriptome data further suggested that exogenous GR24 may inhibit strawberry plant tillering by affecting various phytohormone signaling pathways and the sugar metabolism pathway. In 5 μmol/L GR24-treated plants, the expression level of type-B response regulator (B-ARR) was down-regulated and the expression level of CYTOKININ RESPONSE 1 (CRE1), histidine-containing phosphotransfer protein (AHP), and type-A response regulator (A-ARR) were up-regulated, suggesting the inhibition of the cytokinin (CTK) signaling pathway. The down-regulation of auxin (AUX) and auxin response factor (ARF), as well as the up-regulation of auxin/indole-3-acetic acid (AUX/IAA), led to the inhibition of the indole-3-acetic acid (IAA) signaling pathway. Additionally, the up-regulation of pyrabactin resistance 1/ pyrabactin resistance 1-like (PYR/PYL), non-fermenting 1-related protein kinase 2 (SnRK2), and ABRE binding factors (ABF) and the down-regulation of protein phosphatase 2C (PP2C) were observed in the up-regulated abscisic acid (ABA) signaling pathways. In the sugar metabolism pathway, the up-regulation of invertase (INV), hexokinase (HK), and fructokinase (FRK) and the down-regulation of trehalase (TREH) and beta-amylase (BMY) led to a decreased glucose synthesis and an increased glucose consumption. Therefore, GR24 can effectively inhibit strawberry plant tillering through these pathways, making it an effective reagent for tillering inhibition. Full article
(This article belongs to the Special Issue Progress in Horticultural Crops - from Genotype to Phenotype)
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15 pages, 2551 KiB  
Article
Nitrogen Foliage Application at Anthesis Improves Grain Yield and Quality of Wheat in a Genotype-Dependent Manner
Agronomy 2023, 13(12), 3077; https://doi.org/10.3390/agronomy13123077 - 17 Dec 2023
Viewed by 546
Abstract
Crop quality tends to decrease with an increasing grain yield. Nitrogen is an important nutrient and moderate nitrogen foliage application (NFA) can significantly improve the wheat yield and quality. The objective of this study was to investigate the effect of NFA on the [...] Read more.
Crop quality tends to decrease with an increasing grain yield. Nitrogen is an important nutrient and moderate nitrogen foliage application (NFA) can significantly improve the wheat yield and quality. The objective of this study was to investigate the effect of NFA on the grain yield and quality of wheat and its genotype-dependent variation. Eighteen wheat cultivars were used, and two NFA levels (N1 and N2; 10.70 and 21.40 kg N ha−1 two day−1, respectively) were applied. Significant genotypic differences in the yield and quality were observed among the 18 varieties, and their responses to NFA differed. For nine varieties in the experiment, N1 increased the grain yield, but N2 did not. In contrast, high concentrations of NFA had no effect on the grain yield in the other nine varieties. The protein content and composition and trace element (Fe, Zn, etc.) are all nutrient elements that notably affect the wheat grain quality and yield. NFA significantly increased the grain prolamin and glutelin concentrations in the grains, thereby increasing the total protein concentration. The prolamin, glutelin, and total protein concentrations in the grains of the lower-protein cultivars were more sensitive to NFA than those of the higher-protein cultivars. In addition, NFA significantly decreased the amylose concentration in the grains. By affecting the prolamin, glutelin, and amylose concentrations in the grains, NFA significantly increased the development and stability times of the corresponding wheat flour dough, thereby improving the dough quality. Moreover, NFA reduced the molar ratio of phytic acid to Fe and Zn, increasing the bioavailability of trace elements. The judicious application of nitrogen fertilizer resulted in the synergistic improvement in the yield and quality. Full article
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12 pages, 1063 KiB  
Article
Effect of Varied Salinity on Marigold Flowers: Reduced Size and Quantity Despite Enhanced Antioxidant Activity
Agronomy 2023, 13(12), 3076; https://doi.org/10.3390/agronomy13123076 - 17 Dec 2023
Viewed by 675
Abstract
Salinity is an increasing problem worldwide that limits crop production. The cultivation of salt-tolerant flowers is a potential sustainable strategy for the exploitation of saline soils while avoiding the use of freshwater resources. However, our understanding of how flowers can adapt to salinity [...] Read more.
Salinity is an increasing problem worldwide that limits crop production. The cultivation of salt-tolerant flowers is a potential sustainable strategy for the exploitation of saline soils while avoiding the use of freshwater resources. However, our understanding of how flowers can adapt to salinity is still limited. In this study, we investigated the effects of salinity on a widely-used ornamental plant (Tagetes patula) by submitting three cultivars (cv. Aurora Orange, Fireball, Safari Scarlet) to different salinity levels (0, 50, 100, 300 mM). The plants were grown under controlled conditions and followed over two weeks. We tested the effect of salinity on plant growth and flower production, as well as on the levels of total carotenoids, polyphenols, and flavonoids, and the activities of antioxidant enzymes (catalase, peroxidase activity, ascorbate peroxidase). The findings indicate a substantial decline in both plant growth and flower production under saline conditions. Overall, plant height was ¼ lower, and there were 1/3 less flowers under salinity. Additionally, there was a consistent rise in antioxidant compounds, highlighting the swift response of defense mechanisms, both enzymatic and non-enzymatic, to combat stress. The high levels of antioxidant compounds sustain the use of marigold flowers as a new source of nutritional compounds, with enriched nutritional contents. Yet, cultivation of these plants in saline conditions should carefully consider the pronounced adverse effects observed at high salinity levels (e.g., 100 and 300 mM) on both plant and flower production. Full article
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36 pages, 10950 KiB  
Article
Effectiveness of Oregano and Thyme Essential Oils as Alternatives for Sulfur Dioxide in Controlling Decay and Gray Mold and Maintaining Quality of ‘Flame Seedless’ Table Grape (Vitis vinifera L.) during Cold Storage
Agronomy 2023, 13(12), 3075; https://doi.org/10.3390/agronomy13123075 - 17 Dec 2023
Viewed by 982
Abstract
The current study was carried out over two seasons (2020 and 2021) to assess the effects of preharvest treatments with oregano and thyme essential oils (EOs) as an alternative to the traditional use of sulfur dioxide (SO2) during cold storage of [...] Read more.
The current study was carried out over two seasons (2020 and 2021) to assess the effects of preharvest treatments with oregano and thyme essential oils (EOs) as an alternative to the traditional use of sulfur dioxide (SO2) during cold storage of grape clusters cv. Flame Seedless. Grapevines were sprayed with oregano or thyme essential oils at 2000 or 4000 µL/L two days before harvest. The results confirmed that oregano and thyme EOs treatments reduced the physiological loss in weight, decay incidence, gray mold, rachis browning index, and berry shattering as compared to sulfur dioxide and untreated fruits. In addition, EOs had higher marketable percentage, firmness, and visual appearance cluster scores, while they reduced the deterioration in titratable acidity (TA) and ascorbic acid (AsA) contents, slowing the increases in soluble solids content (SSC) and SSC/TA ratio of berries, and improving total anthocyanin content. Moreover, these EOs delayed berry activities of polyphenol oxidase (PPO), peroxidase (POX), and pectin methylesterase (PME) enzymes during cold storage. Results suggest that preharvest application with either oregano or thyme EOs at 2000 µL/L might be a promising eco-friendly and safe candidate as an alternative to conventional SO2 used to control decay incidence and gray mold rot caused by Botrytis cinerea, and the EOs were effective in maintaining the quality of grape clusters during cold storage for up to 45 days. Full article
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16 pages, 4276 KiB  
Article
Soil Salinity Mapping of Croplands in Arid Areas Based on the Soil–Land Inference Model
Agronomy 2023, 13(12), 3074; https://doi.org/10.3390/agronomy13123074 - 16 Dec 2023
Cited by 1 | Viewed by 627
Abstract
Soil salinization can decrease soil productivity and is a significant factor in causing land degradation. Precision mapping of salinization in agricultural fields would improve farmland management. This study focuses on the cropland in the Manas River Basin, located in the arid region of [...] Read more.
Soil salinization can decrease soil productivity and is a significant factor in causing land degradation. Precision mapping of salinization in agricultural fields would improve farmland management. This study focuses on the cropland in the Manas River Basin, located in the arid region of northwest China. It explores the potential of a soil mapping method, the Soil–Land Inference Model (SoLIM), which only requires a small number of soil samples to infer soil salinization of farmlands in arid areas. The model was utilized to create spatial distribution maps of soil salinity for the years 2009 and 2017, and changes in the distribution were analyzed. The research results indicate: (1) Through the analysis of sample point data, it was observed that soil salinity in the study area tends to accumulate in the surface layer (0–30 cm) in spring and in the subsoil layer (60–90 cm) during the crop growing season, with significant spatial variability. Therefore, it is necessary to conduct detailed salinity mapping. (2) Using field measurements as validation data, the simulation results of the SoLIM were compared with spatial interpolation methods and regression models. The SoLIM showed higher inference accuracy, with R2 values for the simulation results of the three soil layers all exceeding 0.5. (3) The SoLIM spatial inference showed salt accumulation in the northern part and desalination in the southern part. The findings of this study suggest that the SoLIM has the potential to effectively map soil salinization of croplands in arid areas, offering an efficient solution for monitoring soil salinity in arid oasis croplands. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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15 pages, 962 KiB  
Article
Quantifying the Flows of Nitrogen Fertilizer under Different Application Rates in a Soil–Forage Triticale–Dairy Cow System
Agronomy 2023, 13(12), 3073; https://doi.org/10.3390/agronomy13123073 - 16 Dec 2023
Viewed by 900
Abstract
Nitrogen (N) can enhance the biomass and feeding quality of forage crops and advance the growth of the herbivorous livestock industry. Investigating the N fertilizer dynamics in the soil–crop–livestock system is important for resource-use efficiency and environmental safety. By using the 15N-labeled [...] Read more.
Nitrogen (N) can enhance the biomass and feeding quality of forage crops and advance the growth of the herbivorous livestock industry. Investigating the N fertilizer dynamics in the soil–crop–livestock system is important for resource-use efficiency and environmental safety. By using the 15N-labeled technology and the in vitro incubation technique, an experiment was conducted in the North China Plain (NCP) in 2015–2016 to quantify the migration and distribution of N fertilizer in the soil–forage triticale (X Triticosecale Wittmack)–dairy cow system. The results showed that 34.1–37.3% of the applied N fertilizer was absorbed by forage triticale, in which 35.9–39.6% N accumulated in the stems and 60.4–64.1% accumulated in the leaves. In addition, 36.3–39.1% of the applied N fertilizer remained in the 0–100 cm soil layer, in which 81.8–91.3% was distributed in the 0–40 cm soil layer. The remaining 24.6–26.8% of the applied N fertilizer was lost in various ways and 28.1–31.3% of the N fertilizer could be utilized by dairy cows. When N fertilizer was applied between 0–225 kg N ha−1, the increased application of N fertilizer improved the biomass yield from 14.0 to 17.5 t ha−1 and enhanced the N content of the forage triticale from 1.3% to 1.4%; however, it did not significantly affect the distribution rate of N fertilizer in the soil–forage triticale–dairy cow system. The optimum N fertilizer application rate for forage triticale is less than 225 kg N ha–1 to maintain high-efficient N use in the soil–crop–livestock system and reduce the environmental risks in the NCP. Our results quantified the N fertilizer dynamics in the soil–forage triticale–dairy cow system and provided a significant reference for guiding rational strategies of forage triticale cultivation. Full article
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19 pages, 2666 KiB  
Article
Responses of Crop and Soil Phosphorus Fractions to Long-Term Fertilization Regimes in a Loess Soil in Northwest China
Agronomy 2023, 13(12), 3072; https://doi.org/10.3390/agronomy13123072 - 15 Dec 2023
Viewed by 565
Abstract
Contrasting fertilization modifies soil phosphorus (P) transformation and bioavailability, which impact crop P uptake and P migration in the soil profile. A long-term (25-year) fertilizer experiment was employed to investigate crop yield, P uptake and changes in sequentially extracted P fractions in the [...] Read more.
Contrasting fertilization modifies soil phosphorus (P) transformation and bioavailability, which impact crop P uptake and P migration in the soil profile. A long-term (25-year) fertilizer experiment was employed to investigate crop yield, P uptake and changes in sequentially extracted P fractions in the soil profile, and their relationships on a calcareous soil derived from loess material under a winter wheat and summer maize double-cropping system. The experiment involved seven nutrient management treatments: control (CK, no nutrient input), N, NK, NP, and NPK, representing various combinations of synthetic nitrogen (N), phosphate (P), and potassium (K) applications, as well as combinations of NPK fertilizers with either crop residues (SNPK, where S refers to maize stalk or wheat straw) or manure (MNPK, where M refers to dairy manure). Wheat and maize yields were significantly higher with P input fertilizer relative to the P-omitted treatments. Long-term application of P-containing fertilizers markedly raised the contents of inorganic (Pi) and organic (Po) P fractions at 0–20 cm depth compared with the P-omitted treatments. Moreover, both Pi and Po fractions were markedly higher under MNPK than under NPK and SNPK treatments. For achieving high yield for wheat and maize, the critical contents of labile P were 54 and 63 mg kg−1, and those of moderately labile P were 48 and 49 mg kg−1, respectively, defined by the linear plateau model. In addition, the change points of labile P and moderately labile P were 99 and 70 mg kg−1, above which CaCl2-P content significantly increased. Moreover, long-term P input significantly accumulated different P fractions in the deeper soil layers up to 100 cm, with large portions of organic P being a composite of labile and moderately labile P, especially in MNPK treatment. Our results suggest that excessive P supply with organic manure resulted in massive P accumulation in the topsoil and promoted soil P fraction transformation and availability in the deep soil layers, especially in an organic P form that has often been neglected. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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18 pages, 6310 KiB  
Article
Potato Leaf Chlorophyll Content Estimation through Radiative Transfer Modeling and Active Learning
Agronomy 2023, 13(12), 3071; https://doi.org/10.3390/agronomy13123071 - 15 Dec 2023
Viewed by 544
Abstract
Leaf chlorophyll content (LCC) significantly correlates with crop growth conditions, nitrogen content, yield, etc. It is a crucial indicator for elucidating the senescence process of plants and can reflect their growth and nutrition status. This study was carried out based on a potato [...] Read more.
Leaf chlorophyll content (LCC) significantly correlates with crop growth conditions, nitrogen content, yield, etc. It is a crucial indicator for elucidating the senescence process of plants and can reflect their growth and nutrition status. This study was carried out based on a potato nitrogen and potassium fertilizer gradient experiment in the year 2022 at Keshan Farm, Qiqihar Branch of Heilongjiang Agricultural Reclamation Bureau. Leaf hyperspectral and leaf chlorophyll content data were collected at the potato tuber formation, tuber growth, and starch accumulation periods. The PROSPECT-4 radiative transfer model was employed to construct a look-up table (LUT) as a simulated data set. This was accomplished by simulating potato leaves’ spectral reflectance and chlorophyll content. Then, the active learning (AL) technique was used to select the most enlightening training samples from the LUT based on the measured potato data. The Gaussian process regression (GPR) algorithm was finally employed to construct the inversion models for the chlorophyll content of potato leaves for both the whole and single growth periods based on the training samples selected by the AL method and the ground measured data of the potatoes. The R2 values of model validation accuracy for the potato whole plantation period and three single growth periods are 0.742, 0.683, 0.828, and 0.533, respectively with RMSE values of 4.207, 4.364, 2.301, and 3.791 µg/cm2. Compared with the LCC inversion accuracy through LUT with a cost function, the validation accuracies of the GPR_PROSPECT-AL hybrid model were improved by 0.119, 0.200, 0.328, and 0.255, and the RMSE were reduced by 3.763, 2.759, 0.118, and 5.058 µg/cm2, respectively. The study results indicate that the hybrid method combined with the radiative transfer model and active learning can effectively select informative training samples from a data pool and improve the accuracy of potato LCC estimation, which provides a valid tool for accurately monitoring crop growth and growth health. Full article
(This article belongs to the Special Issue Remote Sensing in Smart Agriculture)
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19 pages, 3030 KiB  
Article
Integrating Spectral, Textural, and Morphological Data for Potato LAI Estimation from UAV Images
Agronomy 2023, 13(12), 3070; https://doi.org/10.3390/agronomy13123070 - 15 Dec 2023
Viewed by 682
Abstract
The Leaf Area Index (LAI) is a crucial indicator of crop photosynthetic potential, which is of great significance in farmland monitoring and precision management. This study aimed to predict potato plant LAI for potato plant growth monitoring, integrating spectral, textural, and morphological data [...] Read more.
The Leaf Area Index (LAI) is a crucial indicator of crop photosynthetic potential, which is of great significance in farmland monitoring and precision management. This study aimed to predict potato plant LAI for potato plant growth monitoring, integrating spectral, textural, and morphological data through UAV images and machine learning. A new texture index named VITs was established by fusing multi-channel information. Vegetation growth features (Vis and plant height Hdsm) and texture features (TIs and VITs) were obtained from drone digital images. Various feature combinations (VIs, VIs + TIs, VIs + VITs, VIs + VITs + Hdsm) in three growth stages were adopted to monitor potato plant LAI using Partial Least Squares Regression (PLSR), Support Vector Regression (SVR), random forest (RF), and eXtreme gradient boosting (XGBoost), so as to find the best feature combinations and machine learning method. The performance of the newly built VITs was tested. Compared with traditional TIs, the estimation accuracy was obviously improved for all the growth stages and methods, especially in the tuber-growth stage using the RF method with 13.6% of R2 increase. The performance of Hdsm was verified by including it either as one input feature or not. Results showed that Hdsm could raise LAI estimation accuracy in every growth stage, whichever method is used. The most significant improvement appeared in the tuber-formation stage using SVR, with an 11.3% increase of R2. Considering both the feature combinations and the monitoring methods, the combination of VIs + VITs + Hdsm achieved the best results for all the growth stages and simulation methods. The best fitting of LAI in tuber-formation, tuber-growth, and starch-accumulation stages had an R2 of 0.92, 0.83, and 0.93, respectively, using the XGBoost method. This study showed that the combination of different features enhanced the simulation of LAI for multiple growth stages of potato plants by improving the monitoring accuracy. The method presented in this study can provide important references for potato plant growth monitoring. Full article
(This article belongs to the Special Issue Application of Remote Sensing and GIS Technology in Agriculture)
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20 pages, 2278 KiB  
Article
Effect of Partial Root-Zone Irrigation on Plant Growth, Root Morphological Traits and Leaf Elemental Stoichiometry of Tomato under Elevated CO2
Agronomy 2023, 13(12), 3069; https://doi.org/10.3390/agronomy13123069 - 15 Dec 2023
Viewed by 489
Abstract
The increasing CO2 concentration ([CO2]) in the atmosphere decreases mineral nutrients concentration in crops, whereas it increases water use efficiency (WUE). Partial root-zone irrigation (PRI) could not only increase WUE but also improve plant nutrient status. Yet the effect of [...] Read more.
The increasing CO2 concentration ([CO2]) in the atmosphere decreases mineral nutrients concentration in crops, whereas it increases water use efficiency (WUE). Partial root-zone irrigation (PRI) could not only increase WUE but also improve plant nutrient status. Yet the effect of PRI combined with elevated CO2 concentration (e[CO2]) on the element stoichiometry of tomato leaves remains unknown. This study sought to investigate the responses of leaf mineral nutrients status and element stoichiometric ratios in tomatoes to PRI combined with e[CO2]. Tomato plants (cv. Ailsa Craig) were grown in pots in climate-controlled growth chambers with ambient [CO2] (a[CO2], 400ppm) and elevated [CO2] (e[CO2], 800ppm), respectively. Three irrigation regimes, i.e., full irrigation (FI), deficit irrigation (DI) and PRI, were applied to tomato plants at the flowering stage. The results showed that plants grown under DI and PRI had a similar biomass, enhanced root growth including greater root to shoot ratio, root length, surface area, volume and specific length, and an improved WUE in comparison with FI under e[CO2]. Additionally, under e[CO2], PRI showed an increase in leaf [C](+1.5%) and [N] (+9.3%), no decrease in leaf [K], [Ca], [Mg], [S] and [15N], but a decrease in leaf C/N (−6.6%) as compared with FI. Conclusively, PRI had the ability to improve leaf N concentration, maintain most leaf mineral nutrient concentrations, and optimize or maintain leaf element stoichiometric ratios under e[CO2]. Therefore, PRI would be a practicable mode of irrigation for optimizing WUE and nutrient status in tomato leaves in a future freshwater-limited and higher-CO2 environment. Full article
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12 pages, 1965 KiB  
Article
Rice Straw Mulch Installation in a Vineyard Improves Weed Control and Modifies Soil Characteristics
Agronomy 2023, 13(12), 3068; https://doi.org/10.3390/agronomy13123068 - 15 Dec 2023
Cited by 1 | Viewed by 619
Abstract
After harvesting rice paddy fields, rice straw is a significant problem due to uncontrolled CO2 emissions when the straw is burned. One solution to this problem is to use this rice by-product for mulching planting lines of fruit trees or vineyards with [...] Read more.
After harvesting rice paddy fields, rice straw is a significant problem due to uncontrolled CO2 emissions when the straw is burned. One solution to this problem is to use this rice by-product for mulching planting lines of fruit trees or vineyards with the purpose of controlling weeds and improving soil characteristics. A 3-year experiment was conducted at the Polytechnic University of Valencia (Spain) demonstration vineyard, where rice-straw mulch was installed at three rates in 2021, 24.0, 43.1, and 63.1 t ha−1, and in 2022, 25.0, 37.5, and 50.0 t ha−1. Weeds were mainly controlled with the highest treatment rate (50.0–63.1 t ha−1), as the time of the year for mulch installation is decisive for achieving different weed control rates. On average, mulch decreased soil bulk density (5.4%), and increased the soil organic carbon (24.3%) and water-soluble organic carbon (24.3%) compared to bare soil. Soil temperature changes were observed due to the mulch treatment, with soil temperature lower in bare soil than in mulched soil during the cold season, and higher during the warm season. This effect was highly dependent on the mulch application rate. Soil moisture content was also higher under the mulch treatment, showing a mulch-rate response during the four seasons of the year. The changes in the physical and biological soil properties induced a higher soil respiration rate when mulched soil was compared to bare soil. This study concludes that the use of rice straw as a mulch had positive effects on weed control and soil properties, although three factors concerning mulch management were paramount: rate, the timing of installation, and replacement rate. Full article
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15 pages, 3986 KiB  
Article
Identification and Analysis of the Expression of microRNAs during the Low-Temperature Dormancy Release of Tulipa thianschanica Seeds
Agronomy 2023, 13(12), 3067; https://doi.org/10.3390/agronomy13123067 - 15 Dec 2023
Viewed by 601
Abstract
With versatile biological functions, microRNAs (miRNAs) participate in the regulation of post-transcriptional gene expression in plants. Tulipa thianschanica Regel is a key wild tulip resource of the Liliaceae; however, it reproduces poorly under natural conditions, and the spreading and expansion of its population [...] Read more.
With versatile biological functions, microRNAs (miRNAs) participate in the regulation of post-transcriptional gene expression in plants. Tulipa thianschanica Regel is a key wild tulip resource of the Liliaceae; however, it reproduces poorly under natural conditions, and the spreading and expansion of its population rely on the release of its seeds. In this study, T. thianschanica seeds were subjected to stratification at 4 °C for three different durations: 1 d (physiological dormancy), 20 d (dormancy release), and 40 d (non-dormancy). Nine samples were selected, and miRNA databases were established and annotated. This research revealed information on 34 miRNA families, including 14 newly discovered families and 20 families that were previously known. TpmiRNA167 and TpmiRNA395 were observed to be upregulated. Conversely, TpmiRNA166, which targets the key enzymes involved in antioxidant reactions, was downregulated. Notably, PC-5p-84014 and TpmiRNA159 were found to target TpPYL and TpDELLA, respectively, which influenced the abscisic acid/gibberellin (ABA/GA) ratio. Additionally, TpmiRNA160 and TpmiRNA164 were found to participate in the indole-3-acetic acid signal transduction pathway and interact with ABA, thereby contributing to the release of dormancy. In conclusion, this study provides a comprehensive understanding of the mechanism used to release dormancy in T. thianschanica seeds at the molecular level. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
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18 pages, 4307 KiB  
Article
Low-Temperature Fermented Straw Compost Regulates Rice Growth and Yield by Affecting Soil Physicochemical Properties and the Expression of Important Signaling Pathway Genes
Agronomy 2023, 13(12), 3066; https://doi.org/10.3390/agronomy13123066 - 15 Dec 2023
Viewed by 507
Abstract
Soil physicochemical properties affect crop growth and yield. The addition of fertilizers can improve the soil quality during crop cultivation, leading to increased agricultural production. Organic fertilizers may be produced by composting straw that would otherwise be discarded as agricultural waste, with potential [...] Read more.
Soil physicochemical properties affect crop growth and yield. The addition of fertilizers can improve the soil quality during crop cultivation, leading to increased agricultural production. Organic fertilizers may be produced by composting straw that would otherwise be discarded as agricultural waste, with potential implications for sustainable agricultural development. However, the mechanism underlying the effects of straw compost on crop growth is unknown. In this study, a microbial agent suitable for straw decomposition in cold regions was used for a large-scale biological fermentation. Organic compost was obtained after the decomposition of straw. The straw compost was mixed with soil in different proportions and then used to cultivate Songjing 2 rice plants. The addition of straw compost significantly increased the growth and yield of the rice plants and enhanced various physiological indices. Moreover, the straw compost treatment significantly improved soil physicochemical properties (e.g., pH, enzyme activity, nutrient composition, and microbial diversity) and optimized the soil conditions for crop growth. In addition, the application of straw compost influenced the expression of genes in rice metabolic pathways as well as pathways mediating secondary metabolite synthesis and plant hormone signal transduction. The study data reflect the potential applicability of low-temperature straw fermentation technology for maximizing crop production. Full article
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21 pages, 1803 KiB  
Article
Co-Composting of Hop Bines and Wood-Based Biochar: Effects on Composting and Plant Growth in Copper-Contaminated Soils
Agronomy 2023, 13(12), 3065; https://doi.org/10.3390/agronomy13123065 - 15 Dec 2023
Viewed by 656
Abstract
Decades of intensive use of copper-based fungicides against downy mildew in hops has led to considerable accumulation of copper in topsoil, resulting in toxic effects on plants. Due to its high sorption capacity, the application of co-composted biochar compost might reduce copper toxicity, [...] Read more.
Decades of intensive use of copper-based fungicides against downy mildew in hops has led to considerable accumulation of copper in topsoil, resulting in toxic effects on plants. Due to its high sorption capacity, the application of co-composted biochar compost might reduce copper toxicity, whereby a synergistic effect of the composting process is supposed to occur. Furthermore, biochar addition might improve the composting process itself. Therefore, hop bines were co-composted without as well as with 5 and 20 vol% biochar, respectively. During composting, the temperature and concentration of O2, CO2, H2S, CH4 and NH3 in the compost heaps were regularly recorded. The biochar-free compost as well as the two composts with the biochar addition were characterized with regard to their plant-growing properties and were mixed into soils artificially spiked with different amounts of copper as well as into copper-polluted hop garden and apple orchard soils. The respective soil without the compost addition was used as the control, and further treatments with biochar alone and in combination with biochar-free compost were included in a plant response test with Chinese cabbage. The biochar addition increased the temperature within the compost heaps by about 30 °C and extended the duration of the thermophilic phase by almost 30 days, resulting in a higher degree of hygienization. Furthermore, the application of co-composted biochar composts significantly improved plant biomass by up to 148% and reduced the copper concentration, especially of roots, by up to 35%. However, no significant differences in the biochar-free compost were found in the artificially copper-spiked soils, and the effect of co-composted biochar compost did not differ from the effect of biochar alone and in combination with biochar-free compost. Nevertheless, the co-composting of hop bines with biochar is recommended to benefit from the positive side effect of improved sanitization in addition to reducing copper toxicity. Full article
(This article belongs to the Special Issue Remediation of Heavy Metal/Organic Pollutant Contaminated Farmland)
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14 pages, 1322 KiB  
Article
Investigating the Phytotoxic Potential of Helianthus annuus on Germination and Seedling Morphological Parameters of Two Target Poaceae Species: Spring Barley and Spring Wheat
Agronomy 2023, 13(12), 3064; https://doi.org/10.3390/agronomy13123064 - 14 Dec 2023
Viewed by 736
Abstract
Allelopathy is a phenomenon that has both beneficial and deleterious influences among plants within the same ecosystem. The allelopathic activity of sunflower on cereals, one of the most popular crops in crop rotation, is still poorly studied and understood. This experiment was aimed [...] Read more.
Allelopathy is a phenomenon that has both beneficial and deleterious influences among plants within the same ecosystem. The allelopathic activity of sunflower on cereals, one of the most popular crops in crop rotation, is still poorly studied and understood. This experiment was aimed at evaluating the allelopathic potential of aqueous extracts of different parts of the sunflower (Helianthus annuus L.) grown in the Boreal environmental zone on seedling morphological parameters of spring barley (Hordeum vulgare L.) and spring wheat (Triticum aestivum L.). The following three factors were studied: factor A—two growth stages: flowering sunflower (FS) and ripe sunflower (RS); factor B—three sunflower plant parts: leaves and stems (L + S), heads (H), and roots (R) for extract preparation; factor C—five concentrations (25%, 50%, 75%, and 100% (initial concentration 1:10, referred to as 100% solution)) of sunflower aqueous extracts and deionised water (0%) as a control. FS extract revealed an inhibitory effect on all parameters of spring barley and spring wheat in comparison to RS extract. Extracts from different plant parts differed in their allelopathic effects. Compared with L + S extract, R extract significantly stimulated SG and the morphological characteristics of wheat. H extract significantly inhibited barley RL and SL. With increasing concentrations of the extracts, the values of all investigated parameters were significantly inhibited for both receptor plants. Full article
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14 pages, 493 KiB  
Article
The Supply of Macro- and Microelements to Cotton Plants at Different Distances from a Fertilizer Production Factory
Agronomy 2023, 13(12), 3063; https://doi.org/10.3390/agronomy13123063 - 14 Dec 2023
Viewed by 704
Abstract
Environmental pollution from industrial factories via air deposition is an urgent problem worldwide. Phosphate fertilizers, derived from rock phosphate, are characterized by the presence of potentially toxic elements, such as Zn, Co, Pb, Ni, Cr, Mn, Fe, and Cu, which are dispersed in [...] Read more.
Environmental pollution from industrial factories via air deposition is an urgent problem worldwide. Phosphate fertilizers, derived from rock phosphate, are characterized by the presence of potentially toxic elements, such as Zn, Co, Pb, Ni, Cr, Mn, Fe, and Cu, which are dispersed in the form of solid dust-like materials from the pipes of the factory. This study aimed to investigate the effects of airborne industrial emissions on the chemical and biochemical compositions of cotton grown in the immediate vicinity of a fertilizer factory in Uzbekistan. The composition of airborne dust deposited on the plants, the chemical composition of the cotton leaves before and after washing, as well as that of above- and below-ground plant organs, and their protein contents were determined. The concentrations of macro- and microelements in the leaves and roots were determined using an atomic absorption spectrophotometer. The fluorine contents in the leaves and in the roots were determined using a fluorine-selective electrode. The radius of dispersion of industrial emissions in the air was best described by measuring the fluorine contents in washed and unwashed cotton leaves. The relationships among P, K, Mg, Ca, S, F, and Mn in plant roots and leaves as a function of distance from the pollutant source were analyzed. Based on the fluorine contents in washed and unwashed cotton leaves, the two following zones of technogenic pollution were distinguished: the zone < 5 km from the factory, with high technogenic pollution, and the zone > 5 km from the factory, with moderate technogenic pollution. It was found that the resistance of cotton to air pollution from industrial emissions is determined by the ability of cotton plants to neutralize toxic compounds by increasing the influx of alkaline earth metals into the affected tissues. This study showed the possibility of growing cotton at a distance of >5 km from the fertilizer factory. It is strongly recommended to analyze the chemical composition of plants located in a highly polluted zone only after the dust particles have been washed off of the plant’s surface. Despite the resilience of cotton to industrial pollution, the monitoring of areas identified as pollution zones is recommended. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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16 pages, 2684 KiB  
Article
Substitution of Chemical Fertilizer with Organic Fertilizer Can Affect Soil Labile Organic Carbon Fractions and Garlic Yield by Mediating Soil Aggregate-Associated Organic Carbon
Agronomy 2023, 13(12), 3062; https://doi.org/10.3390/agronomy13123062 - 14 Dec 2023
Viewed by 686
Abstract
This study aimed to explore the impact paths on soil organic carbon and crop yield of completely or partially substituting chemical N fertilizer with organic fertilizers. A four-year field experiment was conducted and included four treatments: (i) N0, no N fertilization application; (ii) [...] Read more.
This study aimed to explore the impact paths on soil organic carbon and crop yield of completely or partially substituting chemical N fertilizer with organic fertilizers. A four-year field experiment was conducted and included four treatments: (i) N0, no N fertilization application; (ii) NF, only synthetic N fertilizer application; (iii) 1/2OF, organic fertilizer substituted for 100% of the synthetic N fertilizer, with the total N application amount being equivalent to half that of NF; and (iv) 1/3OF + 2/3NF, organic fertilizer substituted for 1/3 of the synthetic N fertilizer with the total N application amount from organic and synthetic fertilizer being equivalent to that of NF. Soil total organic carbon (TOC), labile organic-carbon fractions (microbial biomass carbon (MBC), dissolved organic carbon (DOC), particulate organic carbon (POC), and easily oxidized organic carbon (EOC)), the carbon pool management index (CPMI), soil aggregated distribution, and water-stable aggregate-associated organic carbon were determined. Structural equation modeling (SEM) was used to clarify the impact paths of TOC and garlic yield changes under different N fertilizer treatments. Results showed that compared with N0 and NF, 1/2OF and 1/3OF + 2/3NF significantly increased TOC contents by 14.1–20.6%. Soil MBC, DOC, and EOC under 1/2OF were significantly higher than under N0, whereas the 1/3OF + 2/3NF treatment had significantly greater POC. The CPMI was improved by organic fertilizer treatment, with 1/2OF treatment being significantly higher than N0 and NF. The proportion of soil aggregate mass with particle sizes >2 mm was significantly greater under N0, while 1/3OF + 2/3NF significantly increased the proportion of particle sizes of 0.5–2 mm. Soil water-stable aggregate-associated organic carbon showed a trend of first increasing and then decreasing, with the largest particle sizes being 1–2 mm. Moreover, organic fertilizer significantly increased soil water-stable aggregate organic carbon compared with N0 and NF. Similarly, the garlic yield increased with organic fertilizer treatment, while 1/3OF + 2/3NF significantly increased the yield by 37.2% and 15.3%, respectively, compared with N0 and NF. Furthermore, SEM analysis indicated that fertilizer regimes could directly affect TOC and labile organic carbon components by affecting aggregate-associated organic carbon. In particular, aggregates with particle sizes of 0.5–2 mm played an important role, indirectly affecting garlic yield and CPMI. These results indicate that organic fertilizer application has the potential to improve soil organic-carbon content and garlic yield; moreover, fully applying organic fertilizer can reduce N fertilizer input while still maintaining an increase in soil organic carbon and crop yield in the short term. However, caution is still needed regarding of the type and quantity of organic fertilizer added in different cropping systems, and with different soil textures. Full article
(This article belongs to the Special Issue Crop Yield and Quality Response to Cultivation Practices - Series II)
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21 pages, 3394 KiB  
Article
Influence of Extraction Methods on the Phytochemical Profile of Sambucus nigra L.
Agronomy 2023, 13(12), 3061; https://doi.org/10.3390/agronomy13123061 - 14 Dec 2023
Viewed by 689
Abstract
The aim of this work is to evaluate the influence of drying methods, extraction solvent, and extraction methods on the phytochemical profile of Sambucus nigra L. flowers harvested from the western region of Romania. Two drying methods for plant conditioning (room temperature and [...] Read more.
The aim of this work is to evaluate the influence of drying methods, extraction solvent, and extraction methods on the phytochemical profile of Sambucus nigra L. flowers harvested from the western region of Romania. Two drying methods for plant conditioning (room temperature and lyophilization), two extraction solvents (70% ethyl alcohol and water), and three extraction methods (conventional extraction (C), ultrasound-assisted extraction, and microwave extraction) were used. For the evaluation of the phytochemical profile, the following spectrophotometric methods were investigated: total polyphenol content, total antioxidant activity using the DPPH and FRAP methods, and flavonoid content. In addition to the spectrophotometric methods, the individual polyphenols were evaluated using the LC/MS method. Using atomic absorption spectrometry, the macro and microelement content of Sambucus nigra L. flowers was assessed. The results showed that the drying method, the solvent used for extraction, and the extraction method influenced the phytocompound content. The analyses showed that in terms of polyphenols, flavonoid content, and antioxidant activity, high values were recorded for lyophilization-dried samples compared to samples dried at room temperature. Also, higher values were recorded for alcoholic extracts compared to aqueous extracts, but also for extracts obtained by the ultrasound-assisted method, followed by extracts obtained via microwave compared to extracts obtained by conventional extraction. Full article
(This article belongs to the Special Issue Extraction and Analysis of Bioactive Compounds in Crops - Series II)
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24 pages, 1596 KiB  
Review
Synthesis of Zinc Oxide Nanoparticles and Their Applications in Enhancing Plant Stress Resistance: A Review
Agronomy 2023, 13(12), 3060; https://doi.org/10.3390/agronomy13123060 - 14 Dec 2023
Viewed by 1258
Abstract
Biotic and abiotic stress factors are pivotal considerations in agriculture due to their potential to cause crop losses, food insecurity, and economic repercussions. Zinc oxide nanoparticles (ZnO nanoparticles) have gained substantial attention from researchers worldwide for their capacity to alleviate the detrimental impacts [...] Read more.
Biotic and abiotic stress factors are pivotal considerations in agriculture due to their potential to cause crop losses, food insecurity, and economic repercussions. Zinc oxide nanoparticles (ZnO nanoparticles) have gained substantial attention from researchers worldwide for their capacity to alleviate the detrimental impacts of both biotic and abiotic stress on plants, concurrently reducing dependence on environmentally harmful chemicals. This article provides an overview of methods for synthesizing ZnO nanoparticles, encompassing physical vapor deposition, ball milling, hydrothermal methods, solvothermal methods, precipitation methods, microwave methods, microbial synthesis, and plant-mediated synthesis. Additionally, it delves into the absorption, translocation, and biotransformation pathways of ZnO nanoparticles within plants. The emphasis lies in elucidating the potential of ZnO nanoparticles to safeguard plants against biotic and abiotic stress, enhance plant performance, and modulate various plant processes. The article also offers a preliminary exploration of the mechanisms underlying plant stress tolerance mediated by ZnO nanoparticles. In conclusion, ZnO nanoparticles present an environmentally friendly and cost-effective strategy for plant stress management, paving the way for the integration of nanotechnology in sustainable agriculture. This opens new possibilities for leveraging nanotechnology to bolster plant resilience against stress in the ever-changing climate conditions, ensuring global food security. Full article
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14 pages, 2533 KiB  
Article
Analyzing Evapotranspiration in Greenhouses: A Lysimeter-Based Calculation and Evaluation Approach
Agronomy 2023, 13(12), 3059; https://doi.org/10.3390/agronomy13123059 - 14 Dec 2023
Viewed by 592
Abstract
The absence of accurate measurement or calculation techniques for crop water requirements in greenhouses frequently results in over- or under-irrigation. In order to find a better method, this study analyzed the accuracy, data consistency and practicability of the Penman–Monteith (PM), Hargreaves–Samani (HS), Pan [...] Read more.
The absence of accurate measurement or calculation techniques for crop water requirements in greenhouses frequently results in over- or under-irrigation. In order to find a better method, this study analyzed the accuracy, data consistency and practicability of the Penman–Monteith (PM), Hargreaves–Samani (HS), Pan Evaporation (PAN), and Artificial Neural Network (ANN) models. Model-calculated crop evapotranspiration (ETC) was compared with lysimeter-measured crop evapotranspiration (ETC) in the National Precision Agriculture Demonstration Station in Beijing, China. The results showed that the actual ETC over the entire experimental period was 176.67 mm. The ETC calculated with the PM, HS, PAN, and ANN model were 146.07 mm, 189.45 mm, 197.03 mm, and 174.7 mm, respectively, which were different from the actual value by −17.32%, 7.23%, 11.52%, and −1.12%, respectively. The order of the calculation accuracy for the four models is as follows: ANN model > PAN model > PM model > HS model. By comprehensively evaluating the statistical indicators of each model, the ANN model was found to have a significantly higher calculation accuracy compared to the other three models. Therefore, the ANN model is recommended for estimating ETC under greenhouse conditions. The PM and PAN models can also be used after improvement. Full article
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11 pages, 1234 KiB  
Article
Effects of Nitrogen Application Rate on Dry Matter Weight and Yield of Direct-Seeded Rice under Straw Return
Agronomy 2023, 13(12), 3058; https://doi.org/10.3390/agronomy13123058 - 14 Dec 2023
Viewed by 521
Abstract
Straw is an agricultural byproduct that results from the production of many crops, such as cereals, yet it is often considered a waste product. However, straw has both historical precedent and future potential as an agricultural resource. In this study, we aimed to [...] Read more.
Straw is an agricultural byproduct that results from the production of many crops, such as cereals, yet it is often considered a waste product. However, straw has both historical precedent and future potential as an agricultural resource. In this study, we aimed to determine the effects of returning straw to the soil on rice cultivation. To this end, we used the hybrid rice variety Luliangyou Jingling as the test material to study the effect of straw return under four different nitrogen application levels (0 kg N (N1), 120 kg N/hm2 (N2), 150 kg N/hm2 (N3), and 180 kg N/hm2 (N4)) on rice tillering dynamics, leaf area index (LAI), dry matter accumulation, and yield. We found that rice under straw return had a higher number of effective panicles, along with a higher number of grains per panicle, compared to those without straw return. Additionally, the tiller number, LAI, total dry matter, and yield of rice in each main growth period under straw return were higher than those without straw return, and these values increased with an increase in nitrogen application rate. The yield was the highest at 9520.63 kg/hm2 without straw return, while the highest yield with straw return was achieved at 10,738.26 kg/hm2. Our results revealed the optimal nitrogen application level for high yield of two-line direct-seeded rice under straw return, which provides a theoretical reference for the precise reduction of fertilizer application in rice cultivation. Full article
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16 pages, 3892 KiB  
Article
Spatiotemporal Evolution of Precipitation Heterogeneity Characteristics in the Heilongjiang Province from 1961 to 2020
Agronomy 2023, 13(12), 3057; https://doi.org/10.3390/agronomy13123057 - 14 Dec 2023
Viewed by 505
Abstract
Precipitation unevenness significantly influences the rational allocation of water resources and the management of agricultural irrigation. Based on precipitation data from 29 meteorological stations in Heilongjiang Province, China, from 1961 to 2020, this study calculated the precipitation concentration index (PCI), precipitation concentration degree [...] Read more.
Precipitation unevenness significantly influences the rational allocation of water resources and the management of agricultural irrigation. Based on precipitation data from 29 meteorological stations in Heilongjiang Province, China, from 1961 to 2020, this study calculated the precipitation concentration index (PCI), precipitation concentration degree (PCD), and precipitation concentration period (PCP) to analyze the spatial distribution characteristics of precipitation heterogeneity at three distinct timescales: year, maize growth period, and the four stages of the maize growth period. The findings reveal that the rainy season in Heilongjiang Province commences earlier in the southwest compared with the northeast and northwest, with a primary concentration in July. At the annual scale, PCI in southwestern Heilongjiang Province surpasses that in the southeastern region, displaying an approximate east–west gradient in PCD and PCP values ranging from 0.544 to 0.746 and 196 to 203, respectively. During the growth period scale, precipitation concentrates in the southwest and central regions, occurring earlier than in the northeast and northwest. In contrast to the annual scale, the PCI value is smaller, and precipitation predominantly concentrates in mid and late July. Examining the four stages of the maize growth period, PCD generally exhibits a decreasing gradient from west to east. The highest values of PCI and PCD manifest in the southwestern part of Heilongjiang Province, with precipitation concentrated in the middle of each growth stage. The research results serve as a valuable reference for policymakers and stakeholders involved in water resource allocation and agricultural water management in Heilongjiang Province. Full article
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10 pages, 1802 KiB  
Article
Propagation of Clematis ‘Warszawska Nike’ in In Vitro Cultures
Agronomy 2023, 13(12), 3056; https://doi.org/10.3390/agronomy13123056 - 14 Dec 2023
Viewed by 767
Abstract
A micropropagation protocol for growing Clematis ‘Warszawska Nike’ was developed. The MS medium supplemented with 1 mg∙dm−3 BAP showed good results in the case of microshoot initiation (80%). The addition of BAP to the medium at higher concentrations resulted in the formation [...] Read more.
A micropropagation protocol for growing Clematis ‘Warszawska Nike’ was developed. The MS medium supplemented with 1 mg∙dm−3 BAP showed good results in the case of microshoot initiation (80%). The addition of BAP to the medium at higher concentrations resulted in the formation of a large amount of callus tissue at the base of the explant. Of the explants growing on the medium with the lowest cytokinin concentration, 8% flowered. Very quickly, after just 14 days, the explants began to die: some of the leaves that developed in in vitro cultures began to turn yellow and wither. The propagation of shoots was performed in two steps. In the first step, cytokinin BAP and Kin in various concentrations (0.5–2 mg∙dm−3) were added to the MS medium. In the second step, MS medium with the combinations of BAP (0.5 and 1 mg∙dm−3) with IAA or GA3 (1 and 2 mg∙dm−3) was used. The MS medium with 0.5 mg∙dm−3 BAP and 2 mg∙dm−3 GA3 was the best medium for the multiplication stage of clematis. Plants growing on this medium had the largest number of leaves, shoots, and internodes, and were also heavier compared to plants propagated on other media. The proliferated clematis explants were rooted on MS medium with the addition of IAA or IBA in different concentrations (0.5 to 4 mg∙dm−3). Of the concentrations tested, 0.5 mg∙dm−3 IAA was the most effective one for in vitro root induction. The highest percentage of acclimatized plants (75%) was observed when the shoots were rooted on MS medium with 0.5 mg∙dm−3 IAA. Full article
(This article belongs to the Special Issue Plant Tissue Culture and Plant Somatic Embryogenesis)
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Article
Efficacy of Four Insecticides Applied to Fortified Rice with Basil against Major Stored-Product Insect Species
Agronomy 2023, 13(12), 3055; https://doi.org/10.3390/agronomy13123055 - 14 Dec 2023
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Abstract
Rice is one of the most important foods since it is grown in many countries and consumed by the majority of the population. Ensuring food security through the protection of stored-product commodities has become one of the most important priorities worldwide. In this [...] Read more.
Rice is one of the most important foods since it is grown in many countries and consumed by the majority of the population. Ensuring food security through the protection of stored-product commodities has become one of the most important priorities worldwide. In this study, the effects of three insecticidal formulations and an available diatomaceous earth formulation on basil-fortified rice against the major stored-product insects were evaluated. The label dose of each insecticidal formulation was used. Insect mortality was determined after 1, 3, 7, 14 and 21 days for each species. The entire experiment was repeated three times by preparing different lots of treated and untreated rice for each treatment. The results of the diatomaceous earth treatments showed that the most susceptible individuals were Sitophilus oryzae adults and Oryzaephilus surinamensis larvae, while the least susceptible individuals were Rhyzopertha dominica and Tribolium castaneum adults. The tested insecticides were effective against S. oryzae, as mortality was 100%. Between the two pyrethroids, deltamethrin was more effective than cypermethrin in the tested insecticides. Our findings indicate that there are available insecticides on the market which can be obtained successfully for the durable protection of agricultural commodities after the harvest stage. Full article
(This article belongs to the Special Issue Post-harvest Pest and Disease Management)
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