Soybean Production Research Articles

Alleviation of Drought Stress in Soybean [Glycine max (L.) Merril] by Foliar Application of Thiourea on Productivity and Profitability under Rainfed Condition

Background: In changing climatic scenario, plants often face periods of soil and atmospheric water deficits because of scarcity of water availability and deteriorating quality across the globe. Drought stress is the one of the major abiotic factors that reduce plant water status, obstructs photosynthesis, brings oxidative stress hindering soybean productivity. In view of this, bioregulators (thiourea) are innovative agricultural technique used to protect plants, minimizing the adverse effects caused by environmental stress. Therefore, an alternative to improve crop yield under rainfed condition by application of bioregulators like thiourea and suitable varieties are important in order to mitigate stress in soybean production. Methods: The field experiments were conducted in Factorial RBD with three replications. To know the impact of foliar spray of thiourea on growth, physiological parameters, yield parameters, yield and economics of two soybean varieties were carried out during kharif 2020, 2021 and 2022. Result: Long term results showed that, by using MACS 1188 variety of soybean and foliar spray of thiourea at 500 ppm and 750 ppm during the 25 and 55 DAS is a commendatory option and most remunerative for farmers to improve the productivity and profitability of soybean in Northern Transition Zone of Karnataka.

Appropriate Water and Nitrogen Regulation Promotes Soybean Yield Formation and Improves Water–Nitrogen Use Efficiency

To address water scarcity and soil damage in the Hexi Oasis irrigation area of China, a study was conducted on regulating water and nitrogen levels for soybean growth under film drip irrigation over two growing seasons (2020 and 2021). Two irrigation levels were tested: mild deficit (W1, 60–70% of field water capacity, FC) and full irrigation (W2, 70–80% of FC), along with three nitrogen levels: low (N1, 60 kg·ha−1), medium (N2, 120 kg·ha−1), and high (N3, 180 kg·ha−1). The control treatment was no nitrogen with full irrigation (W2N0), totaling seven treatments. Results showed that during both growing seasons, soybean plant height reached its peak at the tympanic ripening stage, while the leaf area index (LAI), net photosynthesis rate (Pn), and transpiration rate (Tr) decreased at the tympanic ripening stage. The highest values for the plant height, LAI, Pn, Tr, yield, and the cost–benefit ratio were observed under the W2N2 treatment, significantly outperforming the W2N0 in all aspects (p < 0.05). Over the two-year period, the plant height and LAI were notably higher by 22.86% and 7.09%, respectively, in the W2N2 treatment compared to the W1N1. Full irrigation under N1 and N2 conditions resulted in an enhanced soybean Pn and Tr. However, under N3 conditions, a deficit-tuned irrigation treatment led to a 15.71% increase in the Pn and a 13.34% increase in the Tr on a two-year average. The W2N2 treatment had the highest yield, with a significant 4.93% increase over the W1N3 treatment on a two-year average. The highest rate of change in yield was observed in W1. The two-year cost–benefit ratio and unilateral water benefit reached their peak values in W2N2 and W1N2, respectively. Water use efficiency (WUE) was lower in N1 but significantly increased by 21.83% on a two-year average in W1N3 compared to W1N2. Additionally, W1 had a 14.21% higher WUE than W2 over two years. N3 had the lowest partial factor productivity of nitrogen, which increased by 17.78% on a two-year average in W2N1 compared to W1N1. All nine indicators related to yield formation and water–nitrogen use efficiency showed a positive correlation (p < 0.05) in this study. The highest composite scores were achieved with the W2N2 treatment in both years using the entropy weight and TOPSIS method. Overall, the W2N2 treatment provides a water and nitrogen combination that enhances soybean water and fertilizer efficiency, making it a promising option for high-yield soybean cultivation with water and nitrogen conservation in the Hexi Oasis irrigation area of China. This study offers valuable insights for achieving efficient soybean production while saving water and reducing nitrogen use.

System fertilization in integrated crop-livestock management favors microbial processes, soil quality and production profitability

Integrated crop-livestock systems with no tillage (ICLS-NT) have emerged as more responsible modes of production. Different fertilization strategies can optimize the productivity and profitability of ICLS-NT. However, it is necessary to understand how these strategies can change soil quality. This study aimed to investigate how different fertilization strategies within the ICLS-NT impact the biochemical and chemical attributes of the soil, as well as the productivity and profitability of the system. An ICLS-NT experiment was conducted with beef cattle grazing in winter and soybean cultivation in summer, structured in a 2×2 factorial arrangement, starting in 2019 and evaluated after 3 years (2021/2022 harvest). The first factor was the timing of fertilization: conventional Fertilization (CF - application of phosphorus and potassium during soybean sowing), and system Fertilization (SF - application of phosphorus and potassium in pasture). The second factor was the application of 100 kg ha–1 of nitrogen to the Brachiaria pasture: with application (+N) or without application (–N), resulting in four treatments distributed in three blocks. The system fertilization showed greater biochemical activity, nutrient availability, forage accumulation, increased animal stocking, and animal weight gain, regardless of the level of nitrogen. The strategy SF+N also provided an increase of 438 kg ha–1 in soybean grain productivity, which added to profits from animal production culminating in 407.35 US$ ha–1 of net income more than what was obtained in reference treatment (CF–N). The findings highlight that applying fertilizers after the crop phase is an effective strategy for replenishing soil nutrients, activating microbial processes and improving soil quality. This approach means a more sustainable agricultural practice, reducing environmental impact and at the same time reinforcing profitability in ICLS-NT.

Nutrient dynamics study and yield optimization for soybean through integrated nutrient and weed management

Soybean production faces many constraints with several factors, such as biotic and abiotic factors, and the crop management practices where inadequate nutrient management leads to a decline in production potential of the crop. Among the biotic factors, exploitation of resources by weeds not only causes a decline in production but also decreases the crop quality. Managing the weeds during the critical period of crop weed competition plays outstanding role in maximizing soybean production. In order to study the influence of integrated nutrient and weed management on nutrient dynamics and yield optimization of soybean an experiment was conducted in Split Plot Design with three nutrient management treatments in main plot {100% recommended dose of fertilizer (RDF), 75% RDF + 25% N through farmyard manure (FYM) + Phosphate solubilizing bacteria (PSB) and 50% RDF + Rhizobium + PSB} and five weed management treatments in the sub-plot (Hand weeding at 15, 30 and 45 DAS, Mechanical weeding at 20 and 40 DAS, Pendimethalin @ 1 kg a.i. ha−1 PE fb Hand weeding at 30 DAS, Propaquizafop @ 0.075 kg a.i. ha−1 PoE fb Hand weeding at 45 DAS, and Weedy check as control). The results indicated that application of 75% RDF + 25% N through FYM + PSB recorded the highest seed yield, nutrient content in seed and uptake of N, P, K, and S in the seed and stover, microbial population, and soil nutrient status. Highest partial factor productivity was recorded under 50% RDF + Rhizobium + PSB. Under weed management, hand weeding recorded the highest growth, yield attributes and nutrient content, but was found to be at par with Pendimethalin @ 1 kg a.i. ha−1 PE fb Hand weeding at 30 DAS and Propaquizafop @ 0.075 kg a.i. ha−1 PoE fb Hand weeding at 45 DAS. Application of 75% RDF + 25% N through FYM + PSB and pendimethalin @ 1 kg a.i. ha−1 fb hand weeding at 30 DAS proves to be an effective strategy for soybean cultivation. The experiment was conducted at the experimental farm of School of Agricultural Sciences, Nagaland University, Medziphema, India.

Associations of physical activity and soybean product consumption with psychological symptoms: a cross-sectional survey of Chinese university students

IntroductionDeclining physical activity among university students has become a concern, with increasingly poor dietary behaviors and other unfavorable factors having an impact on the occurrence of psychological symptoms. Previous studies have analyzed the association between moderate-to-vigorous physical activity (MVPA) and psychological symptoms, but few studies have investigated the association between soy product consumption and these symptoms. In addition, the associations between physical activity and soy product consumption with psychological symptoms have not been investigated.MethodsIn this study, 7267 university students from different regions of China were surveyed regarding physical activity, soy product consumption, and psychological symptoms. Binary logistic regression was used to analyze the associations among MVPA, soy product consumption, and psychological symptoms. A generalized linear model (GLM) was applied to further analyze the associations of MVPA and soy product consumption with psychological symptoms in this population.ResultsThe detection rate of psychological symptoms among Chinese university students was 17.9%, with the rate among female students (18.9%) higher than that among male students (16.6%). The proportion of university students with MVPA < 30 min/d, 30–60 min/d, and > 60 min/d was 76.1%, 19.3%, and 4.6%, respectively, and the proportion with soy product consumption ≤ 2 times/wk, 3–5 times/wk, and ≥ 5 times/wk was 25.8%, 42.4%, and 31.7%, respectively. The GLM showed that compared with university students who had MVPA < 30 min/d and soy product consumption ≤ 2 times/week, those with the lowest risk of developing psychological symptoms had MVPA > 60 min/d and soy product consumption ≥ 6 times/week (OR = 0.198, 95% CI: 0.100–0.393, P < 0.001). This group was followed by university students with MVPA > 60 min/d and soy product consumption 3–5 times/week (OR = 0.221, 95% CI: 0.102–0.479, P < 0.001).ConclusionIn terms of research, there is an association between physical activity and soy product consumption and psychological symptoms among university students. The results of our study suggest that integrated intervention for psychological symptoms among university students is needed from the perspectives of physical activity and dietary behavior to promote good mental health in this population.

Conversion of monocropping to intercropping promotes rhizosphere microbiome functionality and soil nitrogen cycling

Intercropping can increase soil nutrient availability and provide greater crop yields for intensive agroecosystems. Despite its multiple benefits, how intercropping influences rhizosphere microbiome assemblages, functionality, and complex soil nitrogen cycling is not fully understood. Here, a three-year field experiment was carried out on different cropping system with five fertilization treatments at the main soybean production regions. We found that soybean yields in intercropped systems were on average 17 % greater than in monocropping system, regardless of fertilization treatments. We also found that intercropping systems significant increased network modularity (by 46 %) and functional diversity (by 11 %) than monocropping systems. Metagenomics analyses further indicated intercropping promotes microbiome functional adaptation, particularly enriching core functions related to nitrogen metabolism. Cropping patterns had a stronger influence on the functional genes associated with soil nitrogen cycling (R2 = 0.499). Monocropping systems increased the abundance of functional genes related to organic nitrogen ammonification, nitrogen fixation, and denitrification, while functional guilds of nitrate assimilation (by 28 %), nitrification (by 31 %), and dissimilatory nitrate reduction (by 10.1 %) genes were enriched in intercropping systems. Furthermore, we found that abiotic factors (i.e. AP, pH, and Moisture) are important drivers in shaping soil microbial community assemblage and nitrogen cycling. The functional genes include hzsB, and nrfA, and nxrA that affected by these biotic and abiotic variables were strongly related to crop yield (R2 = 0.076 ~ R2 = 0.249), suggesting a key role for maintaining crop production. We demonstrated that land use conversion from maize monocropping to maize-soybean intercropping diversify rhizosphere microbiome and functionality signatures, and intercropping increased key gene abundance related to soil nitrogen cycling to maintain the advantage of crop yield. The results of this study significantly facilitate our understanding of the complex soil nitrogen cycling processes and lay the foundation for manipulating desired specific functional taxa for improved crop productivity under sustainable intensification.

Comparison of grain traits and genetic diversity between Chinese and Uruguayan soybeans (Glycine max L.).

Soybeans (Glycine max L.), originating in China, were introduced to South America in the late 19th century after passing through North America. South America is now a major soybean-producing region, accounting for approximately 40% of the global soybean production. Crops like soybeans gradually adapt to the local climate and human-selected conditions, resulting in beneficial variations during cultivation in different regions. Comparing the phenotypic and genetic variations in soybeans across different regions is crucial to determining the variations that may enhance soybean productivity. This study identified seed-related traits and conducted a genetic diversity analysis using 46 breeding soybean varieties from China and Uruguay. Compared to the Chinese soybean germplasm, the Uruguayan equivalent had a lower 100-grain weight, higher oil content, lower protein content, and higher soluble sugar content. Using ZDX1 gene chips, genetic typing was performed on the 46 breeding varieties. Cluster analysis based on SNP sites revealed significant differences in the genetic basis of Sino-Uruguayan soybean germplasm. Selection analysis, including nucleotide polymorphism (π) and fixation indexes (Fst), identified several genomic regions under selection between Sino-Uruguayan soybean germplasm. The selected intervals significantly enriched gene ontology (GO) terms related to protein metabolism. Additionally, differentiation occurred in genes associated with the oil content, seed weight, and cyst nematodes between Sino-Uruguayan soybean germplasm, such as GmbZIP123 and GmSSS1. These findings highlight the differences in seed-related phenotypes between Sino-Uruguay soybean germplasm and provide genomic-level insights into the mechanisms behind phenotypic differences, offering valuable references for understanding soybean evolution and molecular breeding.

Application of Protein Hydrolysate Improved the Productivity of Soybean under Greenhouse Cultivation

Protein hydrolysates are plant biostimulants containing amino acids, oligopeptides, and peptides in their composition. When supplied to plants, protein hydrolysates (HPs) have been identified to improve nitrogen metabolism, enhance the activity of antioxidant enzymes, boost plant defense response to stresses, and positively impact the quantity and quality of products. Soybean is a crucial global commodity, with nitrogen being the primary nutrient for crop development as it directly affects productivity. This study aimed to evaluate the effect of an HP-based biostimulant on the N metabolism in nodulated soybean plants and their productivity. A greenhouse experiment was conducted to test two modes of application of the 0.20% HP-based biostimulant. Soybean plants, growing in pots, were treated with 0.20% HP either via seed treatment or foliar application (at growth stages V3 and V5). Activities of enzymes and compounds related to N metabolism, gene expression, and productivity components were analyzed. It was observed that the mode of application did not significantly influence the results. The application of HPs increased the concentration of nitrate, amino acids, and ureides in soybean leaves. It also positively altered the expression of genes such as nitrate reductase, urease, and asparagine. Additionally, it enhanced productivity, resulting in plants with a greater number and weight of pods and grains. Therefore, it is possible to consider HPs as a stimulator for increasing soybean productivity, even under non-stressing conditions.

The Biostimulant Potential of Clove Essential Oil for Treating Soybean Seeds

Increasing soybean productivity can be achieved by treating seeds with biostimulants. To this end, an investigation was conducted into the potential of a formulation prepared with clove es-sential oil (CEO) diluted in soybean oil for seed treatment. Soybean seeds were treated with CEO concentrations between 0.5 to 3.0 mL/L, and subjected to germination, vigor, and sanity analyses. The CEO at 1.6 mL/L exhibited favorable outcomes regarding germination, root length, and re-duced fungal infection. In this way, a two-crop field experiment evaluated soybean seeds treated with CEO at 1.6 mL/L. Soybean seeds treated with CEO in the field in 2021/2022 were not different from the controls. However, in 2019/2020, there was a higher percentage of emergence, nodulation, and production of 749 kg/ha more than in the industrial treatment. These results highlight the potential use of CEO as a biostimulant.

Identification of Insect Pests on Soybean Leaves Based on SP-YOLO

Soybean insect pests can seriously affect soybean yield, so efficient and accurate detection of soybean insect pests is crucial for soybean production. However, pest detection in complex environments suffers from the problems of small pest targets, large inter-class feature similarity, and background interference with feature extraction. To address the above problems, this study proposes the detection algorithm SP-YOLO for soybean pests based on YOLOv8n. The model utilizes FasterNet to replace the backbone of YOLOv8n, which reduces redundant features and improves the model’s ability to extract effective features. Second, we propose the PConvGLU architecture, which enhances the capture and representation of image details while reducing computation and memory requirements. In addition, this study proposes a lightweight shared detection header, which enables the model parameter amount computation to be reduced and the model accuracy to be further improved by shared convolution and GroupNorm. The improved model achieves 80.8% precision, 66.4% recall, and 73% average precision, which is 6%, 5.4%, and 5.2%, respectively, compared to YOLOv8n. The FPS reaches 256.4, and the final model size is only 6.2 M, while the number of computational quantities of covariates is basically comparable to that of the original model. The detection capability of SP-YOLO is significantly enhanced compared to that of the existing methods, which provides a good solution for soybean pest detection. SP-YOLO provides an effective technical support for soybean pest detection.

Effect of drying techniques on the stability of volatile compounds and antioxidative activities of dried Thai fermented black soybean (thua nao)

Thua nao, a traditional fermented soybean product in Thailand, is widely consumed as a plant-based food or a condiment due to its distinct flavor, taste, and nutritional benefits. In this research, thua nao samples were produced from black soybeans. After fermentation, various drying methods, including sun drying (SUN), hot air drying (HOT), microwave vacuum drying (MIC), and vacuum drying (VAC) were employed to produce dried thua nao. The dried samples were stored under ambient conditions for 8 months. Results revealed lipid oxidation and the Maillard reaction occurred during storage, leading to a decline in bioactive compounds and antioxidant activities. Volatile aroma compounds were analyzed using solid-phase microextraction coupled with gas chromatography-mass spectrometry, while principal component analysis (PCA) evaluated aroma profile changes during storage. PCA indicated that HOT, MIC, and VAC -treated samples remained stable for up to 4 months, while SUN-treated samples changed after 2 months. It was found that SUN treatment prominently promoted the formation of oxidized volatile compounds associated with fatty-waxy and green attributes. The HOT treatment contributed more to aroma volatile compounds associated with nutty-roasted, floral, woody-smoky, and sweet attributes. While, both MIC and VAC treatments showed a noticeable loss of aroma volatile compounds, they retained higher level of bioactive compounds compared to the other treatments. This information aids in selecting suitable drying techniques for thua nao products and enhances understanding of chemical transformations induced by drying.

Growth and Yield Dynamics in Three Japanese Soybean Cultivars with Plant Growth-Promoting Pseudomonas spp. and Bradyrhizobium ottawaense Co-Inoculation.

Co-inoculation of soybeans with Bradyrhizobium and plant growth-promoting bacteria has displayed promise for enhancing plant growth, but concrete evidence of its impact on soybean yields is limited. Therefore, this study assessed the comparative efficacy of two 1-aminocyclopropane-1-carboxylate deaminase-producing Pseudomonas species (OFT2 and OFT5) co-inoculated with Bradyrhizobium ottawaense (SG09) on the growth, physiology, nodulation efficiency, and grain yield of three major Japanese soybean cultivars: Enrei, Fukuyutaka, and Satonohohoemi. The experiments were conducted in a warehouse under natural light conditions. The treatments included the inoculation of SG09, SG09 + OFT2, and SG09 + OFT5. Compared with Bradyrhizobium inoculation alone, co-inoculation led to significant improvements in nodulation efficiency, growth, and physiological performance in the Enrei and Fukuyutaka cultivars, but not in the Satonohohoemi cultivar. Furthermore, co-inoculation significantly boosted the total nitrogen content and ion uptake in the shoots, ultimately leading to a remarkable improvement in the grain yield in the Enrei and Fukuyutaka cultivars. These findings contribute to clarifying the interplay among Bradyrhizobium, Pseudomonas, and the plant host cultivar. Notably, Bradyrhizobium-Pseudomonas co-inoculation represents a potentially effective biofertilization strategy for soybean production, highlighting promising avenues for sustainable agricultural practices.

Geochemical indices and sedimentation rates in the Pardo River basin, São Paulo state, Brazil

Sediment geochemical indices and sedimentation rates data from the Pardo River watershed, São Paulo State, Brazil, provide relevant reference guidelines for stakeholders to plan future actions aiming to achieve the appropriate management of that hydrographic basin. The watershed includes 20 municipalities where about 650,000 inhabitants are living and whose waters after withdrawal and treatment supply ∼300,000 people in that region. Six sediment cores provided the geochemical and radiometric dataset, which was obtained from sampling sites located in the following cities: Ourinhos, Santa Cruz do Rio Pardo, Águas de Santa Bárbara, Avaré, Botucatu, and Pardinho. The concentration data for some metals were compared with the reference values established by the Brazilian environmental legislation for sediment dredging because currently there is a lack of specific quality guidelines for marine or fluvial sediment in Brazil. Also, the entire dataset was used in the calculation of two traditional geochemical indices, i.e., the enrichment factor (EF) and contamination factor (CF). In some cores, both indices provided insight revealing possible anthropogenic inputs of magnesium oxide (MgO), potassium oxide (K2O), sulfur trioxide (SO3), vanadium oxide (V2O5), copper (II) oxide (CuO), and other constituents due to development of activities related to the crop production. The constant rate of supply (CRS) of the unsupported/excess lead 210 (210Pb) model has been successfully applied to the obtained a radiometric 210Pb dataset, yielding mean values of the mass accumulation rate (MAR) between 0.86 and 7.23 g/(cm2·y) and linear sedimentation rates (LSR) ranging from 2.9 to 7.1 cm/y. Both of these rates exhibited a significant correlation, representing physical weathering processes occurring in the basin. Chemical weathering rates reported in the literature indicate values much lower than the physical weathering rates and such findings have also been confirmed in the current study when the obtained data were compared with results from previous investigations in the Pardo River watershed. The CRS 210Pb chronological model was useful to track historical changes in the MgO and CuO concentration in the sediment cores, allowing curves to be plotted exhibiting major peaks in core 1 (1980–2010) and core 3 (2000–2010), a continuous increase from 1970 onwards until 2010 (core 4), and a sharp increase at the end of the monitoring period, 2017 (cores 5 and 6). Data available for the harvested area at a municipality located within the basin for the period 1990–2022 have indicated a more pronounced increase over the last years in the production of sugar cane, soybeans, and oranges, implying an increasing use of fertilizers and agricultural correctives for crop production, whose chemical composition would justify the trends observed for MgO and CuO concentrations in the sediment cores. The current study also revealed a wide range of significant relations involving the concentration of ferric oxide (Fe2O3) and other analyzed constituents, with iron tending to accumulate in the finer grain sizes (from 0.125 to <0.037 mm) of the sediment. The CRS 210Pb chronological model permitted evaluation of the history of the iron flux up to the present, which could represent baseline guidance levels for indicating future anthropic inputs in the basin.

Profile of mineral nutrients and proteins in soybean seeds (Glycine max (L.) Merrill): Insights from 95 varieties cultivated in Brazil

Soybean (Glycine max (L.) Merrill) stands out as a major source of protein meal for human and animal nutrition. Nevertheless, the increase in soybean yield has been accompanied by a reduction in protein content over the last decades. In this study, we determined the profile of mineral nutrients and total protein in 95 soybean varieties broadly cultivated in Brazil, the world’s largest soybean producer and exporter, to identify a possible association between seed mineral and protein content. Energy-dispersive X-ray fluorescence spectroscopy (EDXRF) was employed to determine the concentration of macro, i.e., potassium (K), phosphorus (P), sulphur (S), calcium (Ca), and micronutrients, i.e., iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). The protein content of soybean seeds was evaluated using the Dumas method. The correlation and clustering between nutrients and proteins were determined using both univariate and multivariate non-parametric tests. Both protein and nutrient concentrations were not homogeneous across soybean seed varieties. It was also revealed that the higher the seed protein content, the higher the S, Mn, and Zn concentrations, whereas the opposite trend was observed for K and P. These results indicate an intricate association between S, Zn, Mn, and total protein content in soybean seeds.

Socio-economic evaluation and technical efficiency of soybean (Glycine max) production in north west, Nigeria: A parametric approach

Socio-economic evaluation and technical efficiency of soybean (Glycine max) production in north west, Nigeria: A parametric approach

Rhizobium Inoculant and Seed-Applied Fungicide Effects Improve the Drought Tolerance of Soybean Plants as an Effective Agroecological Solution under Climate Change Conditions.

Rhizobial inoculation in combination with fungicidal seed treatment is an effective solution for improving soybean resistance to modern climate changes due to the maximum implementation of the plant's stress-protective antioxidant properties and their nitrogen-fixing potential, which will contribute to the preservation of the environment. Model ecosystems at different stages of legume-rhizobial symbiosis formation, created by treatment before sowing soybean seeds with a fungicide (fludioxonil, 25 g/L) and inoculation with an active strain of Bradyrhizobium japonicum (titer 109 cells per mL), were subjected to microbiological, biochemical, and physiological testing methods in controlled and field conditions. Seed treatment with fungicide and rhizobia showed different patterns in the dynamics of key antioxidant enzymes in soybean nodules under drought conditions. Superoxide dismutase activity increased by 32.7% under moderate stress, while catalase increased by 90.6% under long-term stress. An increase in the antioxidant enzyme activity induced the regulation of lipoperoxidation processes during drought and after the restoration of irrigation. Regeneration after stress was evident in soybean plants with a combination of fungicide seed treatment and rhizobial inoculant, where enzyme levels and lipoperoxidation processes returned to control plant levels. Applying seed treatment with fungicide and Rhizobium led to the preservation of the symbiotic apparatus functioning in drought conditions. As proof of this, molecular nitrogen fixation by nodules has a higher efficiency of 25.6% compared to soybeans without fungicide treatment. In the field, fungicidal treatment of seeds in a complex with rhizobia inoculant induced prolongation of the symbiotic apparatus functioning in the reproductive period of soybean ontogenesis. This positively affected the nitrogen-fixing activity of soybeans during the pod formation stage by more than 71.7%, as well as increasing soybean yield by 12.7% in the field. The application of Rhizobium inoculant and fungicide to seeds contributed to the development of antioxidant protection of soybean plants during droughts due to the activation of key enzymatic complexes and regulation of lipoperoxidation processes, which have a positive effect on nitrogen fixation and productivity of soybeans. This is a necessary element in soybean agrotechnologies to improve plant adaptation and resilience in the context of modern climate change.

ChinaSoyArea10m: a dataset of soybean-planting areas with a spatial resolution of 10 m across China from 2017 to 2021

Abstract. Soybean, an essential food crop, has witnessed a steady rise in demand in recent years. There is a lack of high-resolution annual maps depicting soybean-planting areas in China, despite China being the world's largest consumer and fourth-largest producer of soybean. To address this gap, we developed the novel Regional Adaptation Spectra-Phenology Integration method (RASP) based on Sentinel-2 remote sensing images from the Google Earth Engine (GEE) platform. We utilized various auxiliary data (e.g., cropland layer, detailed phenology observations) to select the specific spectra and indices that differentiate soybeans most effectively from other crops across various regions. These features were then input for an unsupervised classifier (K-means), and the most likely type was determined by a cluster assignment method based on dynamic time warping (DTW). For the first time, we generated a dataset of soybean-planting areas across China, with a high spatial resolution of 10 m, spanning from 2017 to 2021 (ChinaSoyArea10m). The R2 values between the mapping results and the census data at both the county and prefecture levels were consistently around 0.85 in 2017–2020. Moreover, the overall accuracy of the mapping results at the field level in 2017, 2018, and 2019 was 77.08 %, 85.16 %, and 86.77 %, respectively. Consistency with census data was improved at the county level (R2 increased from 0.53 to 0.84) compared to the existing 10 m crop-type maps in Northeast China (Crop Data Layer, CDL) based on field samples and supervised classification methods. ChinaSoyArea10m is very spatially consistent with the two existing datasets (CDL and GLAD (Global Land Analysis and Discovery) maize–soybean map). ChinaSoyArea10m provides important information for sustainable soybean production and management as well as agricultural system modeling and optimization. ChinaSoyArea10m can be downloaded from an open-data repository (DOI: https://doi.org/10.5281/zenodo.10071427, Mei et al., 2023).

A Method for Estimating Soybean Sowing, Beginning Seed, and Harvesting Dates in Brazil Using NDVI-MODIS Data

Brazil, as a global player in soybean production, contributes about 35% to the world’s supply and over half of its agricultural exports. Therefore, reliable information about its development becomes imperative to those who follow the market. Thus, this study estimates three phenological stages of soybean crops (sowing, beginning seed, and harvesting dates), identifying spatial–temporal patterns of soybean phenology using phenological metric extraction techniques from Normalized Difference Vegetation Index (NDVI) time-series data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Focused on the state of Paraná, this study validates the methodology using reference data from the Department of Rural Economics (DERAL). Subsequently, the model was applied to the major Brazilian soybean area cultivation. The results demonstrate strong agreement between the phenological estimates and reference data, showcasing the reliability of phenological metrics in capturing the stages of the soybean cycle. This study represents the first attempt, to the best of our knowledge, to correlate the vegetative peak of soybeans with the beginning seed stage at a large scale within Brazilian territory. Amidst the urgent need for the accurate estimation of agricultural crop phenological stages, particularly considering extreme weather events threatening global food security, this research emphasizes the continual importance of advancing techniques for soybean monitoring.

First report of Colletotrichum chlorophyti causing soybean anthracnose in Brazil.

Soybean [Glycine max (L.) Merr.] is one of the world's five major food crops, and Brazil produces the highest share at around 42%. Anthracnose caused by Colletotrichum is an important limiting factor to soybean production. In November 2013, anthracnose symptoms, characterized by brown irregular-shaped lesions on petioles, stems, and pods were observed in soybean fields (1% of incidence) in Vera, Mato Grosso State, Brazil. From the five plants gathered in the field, three leaves along with their corresponding petioles were meticulously chosen for the removal of symptomatic tissues. Sampling of these tissues involved carefully cutting a 0.5 × 0.5 cm fragment in the lesion area. The fragments were disinfected with 70% ethanol for 1 min, followed by 1% sodium hypochlorite for 2 min. Then the fragments were rinsed three times in sterile distilled water, placed on water-agar, and incubated at 25 °C for four days, in a 12/12 h photoperiod. Hyphal tips were transferred to potato dextrose agar (PDA) plates and incubated as previously described for seven days. A Colletotrichum sp. single-spore isolate (LFN0461) was selected, grown, preserved in filter paper, and stored at -80 °C. In 2023, it was reactivated for molecular characterization. On PDA, colony showed a rough-like mycelial growth, violaceous-black (front/reverse), with curved-shaped conidia 14.7 - 28.2 × 2.1 - 8.96 µm (average 18.4 × 4.7 µm). The DNA was extracted from 10-day-old mycelium using the cetyltrimethylammonium bromide (CTAB) method. The rDNA internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone (HIS3), and β-tubulin 2 (TUB2) regions were amplified by polymerase chain reaction (PCR), using the primer pairs ITS-1F + ITS-4 (Gardes and Bruns 1993; White et al. 1990), GDF1 + GDR1 (Guerber et al. 2003), CYLH3F + CYLH3R (Crous et al. 2006), and Bt2A + Bt2B (Glass and Donaldson 1995), respectively. The sequences were deposited in the GenBank database (accession numbers: PP209207 - ITS; PP213392 - GAPDH; PP213393 - HIS3; MN688797 - TUB2). The reconstruction of the multilocus phylogenetic tree revealed that the LFN0461 isolate clustered with C. cholorophyti reference strain (IMI 103806) with 99.9% of Bayesian probability. Given the seed-borne nature of soybean anthracnose (Boufleur et al. 2021; Yang et al. 2013), pathogenicity tests were carried out by soybean seeds inoculation. Fifty seeds of NS6220 IPRO (Nidera) cultivar were inoculated by water restriction method, with LFN0461 colonies grown on PDA amended with mannitol (Machado et al. 2004), while 50 seeds were placed on PDA amended with mannitol as negative control. Soybean seeds remained in contact with the inoculum for 48 hours. Subsequently, seeds were sown in 2 L pots (n = 10) containing sterilized substrate, which were placed in a greenhouse at 25 ± 5 ºC. After 10 days, inoculated soybean seedlings exhibited characteristic necrotic lesions on cotyledons and hypocotyls, while negative control plants remained asymptomatic. Colletotrichum chlorophyti was successfully reisolated from the symptomatic tissues. Currently, C. chlorophyti has been reported to cause soybean anthracnose and infect seeds in the United States (Yang et al. 2013, 2012). Although this pathogen has not been reported since our first observation in 2013 in Brazil, many Colletotrichum isolates are misidentified due to reliance on morphology (Boufleur et al. 2021). To our knowledge, this study is the first report of C. chlorophyti causing soybean anthracnose in Brazil, joining a new group of emergent Colletotrichum spp. associated with this disease.

Integrated examination of the transcriptome and metabolome of the gene expression response and metabolite accumulation in soybean seeds for seed storability under aging stress.

Soybean quality and production are determined by seed viability. A seed's capacity to sustain germination via dry storage is known as its seed life. Thus, one of the main objectives for breeders is to preserve genetic variety and gather germplasm resources. However, seed quality and germplasm preservation have become significant obstacles. In this study, four artificially simulated aging treatment groups were set for 0, 24, 72, and 120 hours. Following an aging stress treatment, the transcriptome and metabolome data were compared in two soybean lines with notable differences in seed vigor-R31 (aging sensitive) and R80 (aging tolerant). The results showed that 83 (38 upregulated and 45 downregulated), 30 (19 upregulated and 11 downregulated), 90 (52 upregulated and 38 downregulated), and 54 (25 upregulated and 29 downregulated) DEGs were differentially expressed, respectively. A total of 62 (29 upregulated and 33 downregulated), 94 (49 upregulated and 45 downregulated), 91 (53 upregulated and 38 downregulated), and 135 (111 upregulated and 24 downregulated) differential metabolites accumulated. Combining the results of transcriptome and metabolome investigations demonstrated that the difference between R31 and R80 responses to aging stress was caused by genes related to phenylpropanoid metabolism pathway, which is linked to the seed metabolite caffeic acid. According to this study's preliminary findings, the aging-resistant line accumulated more caffeic acid than the aging-sensitive line, which improved its capacity to block lipoxygenase (LOX) activity. An enzyme activity inhibition test was used to demonstrate the effect of caffeic acid. After soaking seeds in 1 mM caffeic acid (a LOX inhibitor) for 6 hours and artificially aging them for 24 hours, the germination rates of the R31 and R80 seeds were enhanced. In conclusion, caffeic acid has been shown to partially mitigate the negative effects of soybean seed aging stress and to improve seed vitality. This finding should serve as a theoretical foundation for future research on the aging mechanism of soybean seeds.