Soybean Yield Research Articles

Comparative Analysis of Phytochemicals and Gene Expression in Soybean (Glycine max) Under Acute Moderated and Severe Elevated Ozone: Unravelling the Role of Antioxidant Defence

ABSTRACTThe increasing concentrations of ground‐level ozone (O3) resulting from industrialisation and anthropogenic activities present a substantial environmental threat to agricultural productivity, particularly affecting O3‐sensitive crops such as soybeans. The effects of acute O3 exposure on soybean yield attributes and seed quality and whether soybean showed different detoxification mechanisms in response to moderate and severe O3 stress are not extensively explored. In this study, soybean seedlings were exposed to moderate (80 nmol mol−1) and acute severe (200 nmol mol−1) O3 stress, and then growth parameters, yield attributes, reactive oxygen species (ROS) levels, enzymatic and non‐enzymatic antioxidant properties and associated gene expression in the leaves were assessed. The results revealed that moderate O3 exposure enhanced growth parameters but reduced the 100‐grain weight, while acute severe exposure sharply depressed growth parameters, yield attributes and the 100‐grain weight. Moderate O3 fumigation significantly increased hydrogen peroxide (H2O2) levels and catalase (CAT) activity from 4 to 32 h. Acute severe O3 stress induced the overproduction of superoxide anions (O2.−) and H2O2 during nearly the whole experiment period, but only enhanced superoxide dismutase (SOD) activity at 32 h, and showed no stimulatory effects on CAT activity. Additionally, the relative expression levels of the SOD and CAT gene family in soybean leaves exposed to elevated O3 were upregulated, peaking at 8 h. Moderate O3 treatment enhanced reduced glutathione (GSH) and ascorbate (AsA) levels and increased the activities of AsA–GSH cycle‐related enzymes. In contrast, acute severe O3 exposure inhibited GSH and AsA contents and markedly suppressed AsA–GSH cycle‐related enzymes, particularly from 8 to 32 h. Redundancy analysis indicated that CAT and AsA play crucial roles in scavenging O3‐induced ROS under moderate stress, while ascorbate peroxidase (APX) and GSH were more effective under acute severe stress conditions. These findings provide insights into the differential impacts of acute O3 stress on soybeans, emphasising the importance of considering both crop yield and grain quality in assessing O3 risks to crops.

Far-Red Light Inhibits Soybean Biomass and Yield by Modulating Plant Photosynthesis

Alterations in the light environment can significantly influence soybean morphology and yield formation; however, the effects and mechanisms of different light qualities on these aspects require further investigation. Consequently, we selected soybean cultivars with marked differences in light sensitivity as test materials, conducted experiments with red, blue, and green light qualities against a blue light background, and analyzed parameters related to leaf photosynthetic capacity, chlorophyll fluorescence, morphological characteristics, biomass, and yield variations following different light quality treatments. The results showed that following far-red light treatment, soybean plants exhibited significant shade avoidance syndrome, internode elongation, increased plant height, and a marked reduction in both root and leaf biomass, as well as total biomass. Furthermore, there was a substantial reduction in photosynthetic capacity. This indicated that far-red light exerts an inhibitory effect on soybean growth and yield formation. Red light has basically no regulatory effect on plant morphology and yield, while green light has a yield-increasing effect, but there was a cultivar effect. This study not only enhances our understanding of the mechanisms through which light quality regulates plant photosynthesis but also lays a scientific foundation for future crop light environment management and for the further exploration of light quality’s regulatory potential on crop growth.

Soil test crop response nutrient prescription equations for improving soil health and yield sustainability—a long-term study under Alfisols of southern India

IntroductionEnhancing soil health and nutrient levels through fertilizers boosts agricultural productivity and global food security. However, careful fertilizer use is essential to prevent environmental damage and improve crop yields. The soil test crop response (STCR) is a scientific approach to fertilizer recommendation that ensures efficient use, supporting higher crop production while protecting the environment and preserving resources.MethodologyA long-term field experiment on the STCR approach was initiated in 2017 at the Zonal Agriculture Research Station, University of Agricultural Sciences, Bangalore, India. The experiment aimed to study the impact of STCR-based nutrient prescription along with farmyard manure (FYM) for a targeted yield of soybean (Glycine max), sunflower (Helianthus annuus), dry chili (Capsicum annuum), aerobic rice (Oryza sativa L.), foxtail millet (Setaria italica), okra (Abelmoschus esculentus), and kodo millet (Paspalum scrobiculatum) on yield and changes in soil health in comparison with other approaches of fertilizer recommendation.ResultsThe results showed a significant and positive impact of the integrated use of fertilizer with FYM based on the STCR approach on the productivity of all the crops and soil fertility. Significantly higher yields of soybean (23.91 q ha−1), sunflower (27.13 q ha−1), dry chili (16.67 q ha−1), aerobic rice (65.46 q ha−1), foxtail millet (14.07 q ha−1), okra (26.82 t ha−1), and kodo millet (17.10 q ha−1) were observed in the STCR NPK + FYM approach at yield level 1 compared to the general recommended dose and soil fertility rating approach. This approach outperformed the standard recommendations, enhancing nutrient uptake and efficiency across various crops. Utilizing the principal component analysis, the soil quality index effectively reflected the impact of nutrient management on soil properties, with the STCR NPK + FYM treatment at yield level 1 showing the highest correlation with improved soil physical and chemical parameters.DiscussionThe STCR approach led to improved yield, nutrient uptake, utilization efficiency, and soil health, thanks to a balanced fertilization strategy. This strategy was informed by soil tests and included factors like crop-induced nutrient depletion, baseline soil fertility, the efficiency of inherent and added nutrients through fertilizers and farmyard manure, and the success of yield-targeting techniques in meeting the nutritional needs of crops.

Drought stress mitigation and improved yield in Glycine max through foliar application of zinc oxide nanoparticles.

The impact of climate change on agricultural production is apparent due to declining irrigation water availability vis-à-vis rising drought stress, particularly affecting summer crops. Growing evidence suggests that zinc (Zn) supplementation may serve as a potential drought stress management strategy in agriculture. Field studies were conducted using soybean (Glycine max var. Saba) as a model crop to test whether foliar application of zinc oxide nanoparticles (ZnO-NPs) or conventional Zn fertilizer (ZnSO4) would mitigate drought-related water stress and improve soybean yield. Each fertilizer was foliar applied twice at a two-week interval during the flowering stage. Experiments were concurrently conducted under non-drought conditions (70% field capacity) for comparison. Results showed drought significantly reduced relative water content, chlorophyll-a, and chlorophyll-b in untreated control plants by 35.7%, 47.7%, and 41.4%, respectively, compared to non-drought conditions (p < 0.05). Under drought conditions, ZnO-NPs (200mg Zn/L) led to 33.1% and 20.7% increase in chlorophyll-a and chlorophyll-b levels, respectively, compared to ZnSO4 at 400mg Zn/L. Likewise, catalase, peroxidase and superoxide dismutase activities increased by 62.6%, 39.5% and 28.5%, respectively, with ZnO-NPs (200mg Zn/L) under drought compared to non-drought conditions. Proline was significantly increased under drought but was remarkably suppressed (~ 54% lower) with ZnO-NPs (200mg Zn/L) treatment. More importantly, the highest seed yield was observed with ZnO-NPs (200mg Zn/L) treatment under drought (39% higher than untreated control) and non-drought (79.4% higher than control) conditions. Overall, the findings suggest that ZnO-NPs could promote seed yield in soybean under drought stress via increased antioxidant activities, increased relative water content, decreased stress-related proline content, and increased photosynthetic pigments. It is recommended that foliar application of 200mg Zn/L as ZnO-NPs could serve as an effective drought stress management strategy to improve soybean yield.

Integration of Optical and Synthetic Aperture Radar Data with Different Synthetic Aperture Radar Image Processing Techniques and Development Stages to Improve Soybean Yield Prediction

Predicting crop yield throughout its development cycle is crucial for planning storage, processing, and distribution. Optical remote sensing has been used for yield prediction but has limitations, such as cloud interference and only capturing canopy-level data. Synthetic Aperture Radar (SAR) complements optical data by capturing information even in cloudy conditions and providing additional plant insights. This study aimed to explore the correlation of SAR variables with soybean yield at different crop stages, testing if SAR data enhances predictions compared to optical data alone. Data from three growing seasons were collected from an area of 106 hectares, using eight SAR variables (Alpha, Entropy, DPSVI, RFDI, Pol, RVI, VH, and VV) and four speckle noise filters. The Random Forest algorithm was applied, combining SAR variables with the EVI optical index. Although none of the SAR variables showed strong correlations with yield (r &lt; |0.35|), predictions improved when SAR data were included. The best performance was achieved using DPSVI with the Boxcar filter, combined with EVI during the maturation stage (with EVI:RMSE = 0.43, 0.49, and 0.60, respectively, for each season; while EVI + DPSVI:RMSE = 0.39, 0.49, and 0.42). Despite improving predictions, the computational demands of SAR processing must be considered, especially when optical data are limited due to cloud cover.

Assessing the impact of tillage practices and nutrient levels on the growth and productivity of Ethopian mustard (Brassica carinata L.) - soybean (Glycine max (L.) Merr.) cropping system

BackgroundAn importance of tillage, inorganic and organic nutrient sources in the mustard - soybean cropping system lies in their ability to enhance soil fertility, improve nutrient availability, optimize crop growth and yield, and promote sustainable agricultural practices. Any cropping system’s sustainability could be increased by implementing better management techniques like zero and reduced tillage with residue retention and better nutrient sources.ResultsA field experiment was conducted for four consecutive seasons (Winter 2019 to Rainy 2021) to compare the two enhanced management practices, zero and reduced tillage to conventional tillage across four levels of nutrient sources: 75 and 100% recommended dose of nitrogen through FYM and 75 and 100% recommended dose of fertilizers through urea, single super phosphate and muriate of potash in a two years experiment. Experiment results were evaluated in terms of nutrient status, profitability and productivity of Mustard-Soybean cropping system. The results show a substantial improvement in yield, nutrient status, and overall yield performance of mustard and soybean when using the full recommended dose of fertilizers combined with reduced tillage and mulching, compared to other treatment methods. The implementation of reduced tillage practices recorded significantly higher yield of mustard and soybean over conventional and zero tillage.ConclusionSystem productivity and profitability i.e. mustard equivalent yield, productivity, gross returns, net returns, profitability and B: C (benefit: cost) was found to be improved with reduced tillage and 100% recommended dose of fertilizer under reduced tillage practices. To enhance cropping system productivity in various sub-humid regions worldwide, farmers can adopt reduced tillage techniques combined with the full recommended dose of fertilizers (100% RDF).

Planting time and variety effects on biomass, harvest index, and yield of irrigated soybean in mid‐Southern United States

AbstractSoybean [Glycine max (L.) Merr.] biomass and grain yield has increased over the past several decades in the mid‐southern United States. This is attributable to technological advances and improved management strategies. However, a better understanding of biomass accumulation and partitioning is needed to improve our knowledge base of varietal growth habits relative to yield, planting date, and harvest index (HI). Field experiments within a split plot arrangement in a randomized complete block design were established in 2017 and 2018 in Stoneville, MS. The study aimed to evaluate the effect of early (late‐April or mid‐May) and late (late‐May) planting on biomass, HI, and yield amongst eight soybean varieties. Soybean total biomass accumulation was collected at multiple development stages, including V4, R2, mid R5, mid R6, and R8, and partitioned into senesced leaves, pods, and seeds. Overall, the planting date had no effect on yield, HI, and biomass accumulation at any of the growth stages. Yet, the interaction between planting date and variety significantly affected biomass accumulation at the mid R5 stage. Contrarily, the variety selection significantly affected yield, HI, and biomass accumulation at all growth stages except mid R6. The total biomass accumulation at R8 was greatest for Asgrow 46X6, Asgrow 4632, Terral 4857X, Terral 48A76, and Credenz 4748, when pooled over planting dates. Averaged across two planting dates, the greatest yield was produced by Terral 48A76, Asgrow 4632, and Asgrow 46X6. Furthermore, averaged across site‐years, HI was greatest for Asgrow 4632 and Terral 48A76. Based on the results of this study, evaluating soybean HI rather than overall biomass accumulation may be more beneficial for variety selection decisions.

Detection of Candidate Genes and Development of KASP Markers for Pod Length and Pod Width by Combining Genome-Wide Association and Transcriptome Sequencing in Vegetable Soybean

Vegetable soybeans are one of the most important vegetable types in East Asia. The yield of vegetable soybeans is considerably influenced by the size of their pods. To facilitate the understanding of the genetic basis of the pod length and width in vegetable soybeans, we conducted a genome-wide association study (GWAS) and transcriptome sequencing. Four quantitative trait loci, namely, qGPoL1, qGPoL2, qGPoW1, and qGPoW2, were mapped via GWAS analysis. Through the integration of gene function annotation, transcriptome sequencing, and expression pattern analysis, we identified Glyma.06G255000 and Glyma.13G007000 as the key determinants of the pod length and width in vegetable soybeans, respectively. Furthermore, two kompetitive allele-specific polymerase chain reaction (KASP) markers, namely, S06-42138365 (A/T) and S13_628331 (A/T), were developed and effectively validated in 27 vegetable soybean accessions. Overall, our research identified genes that regulate the pod length and width and determined KASP markers for molecular marker-assisted selection breeding. These findings have crucial implications for the improvement of soybean crops and can contribute to the development of efficient breeding strategies.

Effect of Different Organic Liquid Formulations on the Growth and Yield of Soybean: A Case Study from North Konkan Region of Maharashtra

This case study investigates the influence of the six different organic formulations on the growth and yield parameters of soybean (Glycine max L.), which is a popular vegetable oilseed in India. A Randomized Block Design (RBD) with four replications was considered to carry out the field experiment during rabi seasons of year 2022-23. Well-formulated organic liquids, namely Jeevamrut, Panchgavya, Vermiwash, Cowdung wash, Cow urine, and a Control, were applied as part of an integrated nutrient management (INM) approach. Key observations were recorded for various parameters such as plant height, number of branches per plant, number of pods per plant, length of pod, number of seeds per pod, test weight, pod yield, seed yield, and straw yield. The study indicate that Panchgavya (T2) was most effective among the treatments, showing highest seed yield of 1223 kg/ha and a corresponding straw yield of 2144.5 kg/ha. The outcomes of the study would be beneficial for other crops currently facing many challenges related to quality and yield due to the use of chemical-based treatments.

Early Modeling of the Upcoming Landsat Next Constellation for Soybean Yield Prediction Under Varying Levels of Water Availability

The upcoming Landsat Next will provide more frequent land surface observations at higher spatial and spectral resolutions that will greatly benefit the agricultural sector. Early modeling of the upcoming Landsat Next products for soybean yield prediction is essential for long-term satellite monitoring strategies. In this context, this article evaluates the contribution of Landsat Next’s improved spectral resolution for soybean yield prediction under varying levels of water availability. Ground-based hyperspectral data collected over five cropping seasons at the Brazilian Agricultural Research Corporation were resampled to Landsat Next spectral resolution. The spectral dataset (n = 384) was divided into calibration and external validation datasets and investigated using three strategies for soybean yield prediction: (1) using the reflectance from each spectral band; (2) using existing and new vegetation indices developed based on three general equations: Normalized Difference Vegetation Index (NDVI-like), Band Ratio Vegetation Index (RVI-like), and Band Difference Vegetation Index (DVI-like), replacing the traditional spectral bands by all possible combinations between two bands for index calculation; and (3) using a partial least squares regression (PLSR) model composed of all Landsat Next spectral bands, in comparison to PLSR models using Landsat OLI and Sentienel-2 MSI bands. The results show the distribution of the new spectral bands over the most prominent changes in leaf reflectance due to water deficit, particularly in the visible and shortwave infrared spectrum. (1) Band 18 (centered at 1610 nm) had the highest correlation with yield (R2 = 0.34). (2) A new vegetation index, called Normalized Difference Shortwave Vegetation Index (NDSWVI), is proposed and calculated from bands 19 and 20 (centered at 2028 and 2108 nm). NDSWVI showed the best performance (R2 = 0.37) compared to traditional existing and new vegetation indices. (3) The PLSR model gave the best results (R2 = 0.65), outperforming the Landsat OLI and Sentinel-2 MSI sensors. The improved spectral resolution of Landsat Next is expected to contribute to improved crop monitoring, especially for soybean crops in Brazil, increasing the sustainability of the production systems and strengthening food security in Brazil and globally.

Influence of Different Sources and Levels of Phosphorus on Nutrient Use Efficiency (NUE) and Properties of Low Calcareous Soil

A field experiment was conducted during kharif season of 2023 at Post Graduate Instructional Farm, College of Agriculture, Pune to study the impact of different phosphorus sources and levels on soybean growth and nutrient uptake in low calcareous soil. The experiment was laid out in randomized block design having eight treatments with three replications. The treatments comprised T1 - Absolute control, T2 - RDF (50:75:45 kg ha-1 N: P2O5: K2O), T3 - 50% P2O5 through PROM, T4 - 75% P2O5 through PROM, T5 - 100% P2O5 through PROM, T6 - 100% P2O5 through DAP + FYM @12.5 t ha-1, T7 - 100% P2O5 through SSP + FYM @12.5 t ha-1 and T8 - 100% P2O5 through vermicompost. The soil of experimental site was clay loam in texture. The findings of the present investigation revealed that the higher nutrient use efficiency was registered in treatment 100% P2O5 through SSP + FYM @12.5 t ha-1 (16.25 kg kg-1). The application of 100% P2O5 through PROM recorded higher nutrient use efficiency (13.31 kg kg-1) over RDF (11.52 kg kg-1). In respect of agronomic nutrient use efficiency, 100% P2O5 through SSP + FYM @12.5 t ha-1 registered higher nitrogen (40 kg grain kg nutrient-1), phosphorus (26 kg grain kg nutrient-1) and potassium efficiency (44 kg grain kg nutrient-1) to soybean crop. The agronomic efficiency of nitrogen, phosphorus and potassium was observed higher in treatment 100% P2O5 through PROM over treatment RDF. After harvest of crop the soil pH was remained unaffected while the electrical conductivity of soil was significantly higher in 100 % P2O5 through vermicompost and PROM to soybean crop. The application of 100% P2O5 either through vermicompost or PROM recorded at par organic carbon content in soil (0.66% and 0.64% respectively). The application of 100% P2O5 through PROM significantly reduced calcium carbonate (6.29%) in soil. The 100% P2O5 through SSP + FYM @12.5 t ha-1 showed higher available nitrogen in soil (297.33 kg ha-1) while the application of 100% P2O5 through DAP + FYM @12.5 t ha-1 exhibited higher level of available phosphorus and potassium content in soil (41.33 and 745.33 kg ha-1, respectively). Further, the application of 100% P2O5 through vermicompost was also significantly superior in available micronutrients like iron (5.7 mg kg-1), manganese (9.9 mg kg-1), zinc (4.6 mg kg-1) and copper (10.4 mg kg-1). The application of 100% P2O5 through PROM registered significantly higher available nitrogen (287.33 kg ha-1), available phosphorus (37.33 kg ha-1), available potassium (737.67 kg ha-1), available micronutrients viz. iron (5.4 mg kg-1), manganese (9.2 mg kg-1), zinc (4.4 mg kg-1) and copper (10.4 mg kg-1) over recommended dose of fertilizers. In general, the integration of organic fertilizers, FYM, PROM and vermicompost, with chemical fertilizers can significantly enhance nutrient use efficiency, soil nutrient content, improve soil health and increase soybean yield in low calcareous soils.

Soybean yield is positively linked to organic matter, but planting date remains more influential

AbstractEstablishing connections between soil health indicators and crop performance will help ensure that tests recommended to farmers relate to outcomes of interest. This study assessed the relationship of soybean [Glycine max (L.) Merr] yield with three common soil health indicators: soil organic matter (SOM), permanganate oxidizable carbon (POXC), and autoclaved citrate extractable nitrogen (ACE‐N). These tests were assessed alongside other factors (soil test phosphorus, soil test potassium [STK], mapped clay, planting date, summer precipitation, and location). Soil samples were collected from 457 producer‐managed fields between 2019 and 2021 in Arkansas, Michigan, North Carolina, and Wisconsin. Planting date and yield were reported by producers, while mapped clay and rainfall were determined using publicly available data. Simple linear regression was used to assess the relationship between soil health indicators and yield: the natural log of SOM and POXC were positively associated with soybean yield (R2 = 0.07, p &lt; 0.001; R2 = 0.03, p &lt; 0.001), while ACE‐N was not (p = 0.872). Multiple linear regression was used to further test the relationship of SOM and POXC with yield, while accounting for other factors that contribute to soybean yield. Models explained 27% of variation in yield, with significant factors including SOM or POXC, soybean planting date, STK, and mapped clay. Based on standardized coefficients, planting date was the most influential factor associated with yield. Broadly, our results indicate that improvements in yield are linked to higher SOM, but management decisions like planting early are critical for achieving high yields.

Soil P-stimulating bacterial communities: response and effect assessment of long-term fertilizer and rhizobium inoculant application

BackgroundPhosphorus (P) plays a vital role in plant growth. The pqqC and phoD genes serve as molecular markers for inorganic and organic P breakdown, respectively. However, the understanding of how P-mobilizing bacteria in soil respond to long-term fertilization and rhizobium application is limited. Herein, soil that had been treated with fertilizer and rhizobium for 10 years was collected to investigate the characteristics of P-mobilizing bacterial communities. Five treatments were included: no fertilization (CK), phosphorus fertilizer (P), urea + potassium fertilizer (NK), NPK, and PK + Bradyrhizobium japonicum 5821 (PK + R).ResultsThe soybean nodule dry weight was highest in the P treatment (1.93 g), while the soybean yield peaked in the PK + R treatment (3025.33 kg ha− 1). The abundance of the pqqC gene increased in the rhizosphere soil at the flowering-podding stage and in the bulk soil at the maturity stage under the P treatment, while its abundance increased in the bulk soil at the flowering-podding stage and in the rhizosphere soil at the maturity stage under the PK + R treatment. The abundance of the phoD gene was enhanced in the bulk soil at the flowering-podding stage under the PK + R treatment. The Shannon and Ace indexes of pqqC- and phoD-harboring bacteria were higher in the rhizosphere soil at maturity under the PK + R treatment compared to other treatments. Furthermore, a comprehensive analysis of the neutral community model and co-occurrence pattern demonstrated that the application of P fertilizer alone led to an increase in the distribution and dynamic movement of pqqC-harboring bacteria, but resulted in a decrease in complexity of network structure. On the other hand, rhizobium inoculation enhanced the distribution and dynamic movement of phoD-harboring bacteria, as well as the stability and complexity of the network structure. Pseudomonas and Nitrobacter, as well as Steptomyces, Stella, and Nonomuraea, may be crucial genera regulating the composition and function of pqqC- and phoD-harboring communities, respectively.ConclusionsThese findings affirm the crucial role of fertilization and rhizobium inoculation in regulating pqqC- and phoD-harboring bacterial communities, and highlight the significance of long-term phosphate-only fertilization and rhizobium inoculation in enhancing dissolved inorganic phosphorus and mineralized organophosphorus, respectively.

Influence of Different Sources and Levels of Phosphorus on Yield and Quality of Soybean in Low Calcareous Soil

Influence of Different Sources and Levels of Phosphorus on Yield and Quality of Soybean in Low Calcareous Soil

Effect of Level of Sulphur and Phosphorus on Yield and Quality of Soybean Grown in Inceptisol

The field experiment was conducted during Kharif 2017 at Post Graduate Research Farm, Rajarshee Chhatrapati Shahu Maharaj, College of Agriculture Kolhapur, with the view to study the effect of levels of sulphur and phosphorus on yield and quality of soybean grown in inceptisol. The soil of the experimental site was slightly alkaline in reaction, very low in available nitrogen, medium in available phosphorus and medium in available potassium and deficient in available sulphur. The field experiment was carried out in Factorial Randomized Block Design with three replications and sixteen treatments comprising four levels of sulphur (0, 20, 40, and 60 kg ha-1) through elemental sulphur and four levels of phosphorus (0, 75, 100, and 125 kg ha-1) through DAP. The result indicated that the significantly highest grain yield (27.20 q ha-1, 25.04 q ha-1 respectively) was recorded by application of sulphur and phosphorus at 60 kg ha-1 (S4) and 100 kg ha-1 (P3) than rest of the sulphur and the phosphorus levels. The application of (S4, P3) at 60 kg ha-1 and 100 kg P ha-1 showed significantly highest straw yield (38.85 q ha-1, 35.50 q ha-1 respectively) than rest of the combination of sulphur and Phosphorus levels. The quality parameter records highest percent of 1000 grain weight, oil content and oil yield were found in 60 kg S along with 100 kg P ha-1 while the lowest seed yield, 1000 grain weight and oil content were found in control. Therefore, application of 60 kg S with 100 kg P appeared as the promising practice for obtaining higher seed yield and better quality of Soybean.

Combined Effect of Arbuscular Mycorrhizal Fungi and Bradyrhizobium japonicum on Growth, Yield and Nodulation in Soybean

Response of soybean for combined application of AM fungi and Bradyrhizobium japonicum were studied in pot culture experiment in completely randomized design (CRD). Dual inoculation of AM fungi and B. japonicum improved growth, yield, AMF colonization and nodulation in soybean plant, in comparison to single inoculation. Increase in the level of AMF inoculation promoted the growth significantly. Dry weight of the plant was 5.54 g/ plant and 6.02 g/ plant in plants treated with B. japonicum and AMF respectively, which significantly increased to 7.36 g/ plant up on combined application. Similar results were obtained in plant height, No. of pods /plant, seed index, nodulation, AMF density and colonization and chlamydospore population in soybean rhizosphere. Thus, the experiment signifies the importance of combined application for the improvement of crop growth and yield.

Winter Cover Cropping in Sustainable Production Systems: Effects on Soybean and Synergistic Implications for Rhizosphere Microorganisms.

The aim of this study was to evaluate the effects of winter cover crops (CCs) on soybean agronomic performance and their implications for different physiological groups of rhizosphere microorganisms in two sustainable production systems. The production techniques for rye, peas, and oats are well known, but their suitability as CCs for soybean (organic and low-input) production needs to be examined. After two years of trials, soybean yields among the two tested winter CCs (peas and oats (P + O) and rye (R)) were statistically significant only for P + O. The soybean yield in succession to P + O as winter CCs was 3.0 t ha-1, whereas in succession to R, it was 2.7 t ha-1, and in the control plot, it was 2.6 t ha-1. The average soybean grain protein content was in the range of 40 to 41% dry matter (DM), while the oil content ranged from 20 to 22% DM. Protein and oil content primarily depends on the selected soybean variety and it is confirmed through this study that, in the studied system, we can obtain adequate grain nutritional quality. The results indicate an increase in the abundance of total bacteria, ammonifiers, and free N2-fixing bacteria in the rhizosphere, depending on the selected CCs, and differences between the tested production systems. According to this study, winter cover crops (CCs), including peas and oats (P + O) and rye (R), can be included in crop rotation for soybean. CCs can be the answer to agro-biodiversity empowerment in less diverse soybean cropping systems, along with other benefits that CCs can provide at the level of crop rotation. In addition, in almost all aspects of the study, organic production was ahead of low input. Low input is an adequate production system if there are no opportunities for organic certification and for producers who are aware of the advantages of sustainable systems, and it can also represent a transitional path towards regenerative agriculture or organic production.

Enhanced seed yield of full-season soybean when rotated with cereals and cover crops as compared to monoculture in a long-term experiment

Soybeans are of great importance to the global economy, but the cultivation as monoculture has shown several negative environmental implications in the long-term. Long-term studies demonstrate the cumulative effects of rotations on soil variables, but few studies have considered changes during consecutive years in a time series of soybean as a monoculture. The inclusion of cereals and cover crops in rotation with soybean increases the intensification sequence index (ISI, time with crops actively growing during the year) and increases in soybean yield are expected. In line with this, some studies suggest that only including a winter cover crop will increase ISI and raise production. However, these comparisons have not been made in the long term. The objectives of this work were to: i) compare the evolution of full-season soybean yield and production when sowed as monoculture and in cropping sequences that include cereal crops and cover crops, and ii) quantify a yield gap in full-season soybean due to monoculture by evaluating the long-term residual effect of crop sequences with different land occupation. Soybean yield time series in a 14-years period in rotation or as monoculture were studied in a long-term field experiment under no-tillage established in 2006 in the Northern Pampas region of Argentina. Rotations consisted in sequences that included soybean (S), maize (M) and wheat (W), and also incorporated wheat as a winter cover crop (CC): S-S, CC/S-CC/S, S-W/S-M, CC/S-W/S-M, M-W/S, and CC/M-W/S, with ISI values of 0.39, 0.69, 0.55, 0.64, 0.65 and 0.80, respectively. In 2021/22 season, full-season soybean was planted in all plots as a "test" crop, to evaluate the long-term residual effect of sequences with different intensification indexes. Seed yield averaged 3249 kg ha−1 among years. During the 14 years under study, seed yield in S-W/S-M surpassed S-S by 28 % in 6 out of 14 years. The differences between S-S with respect to this sequence were observed consistently from the ninth crop season (i.e. since 2017/18). The inclusion of a cover crop within a soybean monoculture (i.e. CC/S-CC/S) showed similar seed yields as in S-S in 11 out of 14 years. The analysis of the test crop showed yield-gaps when soybeans were grown as monoculture (seed yield in rotations minus seed yield in S-S) of 9, 20, 27, 21 and 31 % for CC/S-CC/S, S-W/S-M, CC/S-W/S-M, M-W/S and CC/M-W/S, respectively. In summary, soybean in rotation with cereals showed an average increase of ca. 346 kg ha−1 and including a cover crop within a soybean monoculture did not increase seed yield at the levels observed when rotated with cereals. Finally, when estimating seed yield-gaps in soybean, it is important to set in which rotation soybean is placed, since a higher maximum yield is expected to happen when soybean follows a more intensified rotation.

Effect of different fertilizer levels and seed treatments on growth and yield of soybean (Glycine max L. Merrill)

Effect of different fertilizer levels and seed treatments on growth and yield of soybean (Glycine max L. Merrill)

Changes in the Yield Effect of the Preceding Crop in the US Corn Belt Under a Warming Climate.

Crop rotation has been widely used to enhance crop yields and mitigate adverse climate impacts. The existing research predominantly focuses on the impacts of crop rotation under growing season (GS) climates, neglecting the influences of non-GS (NGS) climates on agroecosystems. This oversight limits our understanding of the comprehensive climatic impacts on crop rotation and, consequently, our ability to devise effective adaptation strategies in response to climate warming. In this study, we examine the impacts of both GS and NGS climate conditions on the yield effect of the preceding crop in corn-soybean rotation systems from 1999 to 2018 in the US Midwest. Using causal forest analysis, we estimate that crop rotation increases corn and soybean yields by 0.96 and 0.22 t/ha on average, respectively. We then employ statistical models to indicate that increasing temperatures and rainfall in the NGS reduce corn rotation benefits, while warming GS enhances rotation benefits for soybeans. By 2051-2070, we project that warming climates will reduce corn rotation benefits by 6.74% under Shared Socioeconomic Pathway (SSP) 1-2.6 and 17.18% under SSP 5-8.5. For soybeans, warming climates are expected to increase rotation benefits by 8.36% under SSP 1-2.6 and 13.83% under SSP 5-8.5. Despite these diverse climate impacts on both crops, increasing crop rotation could still improve county-average yields, as neither corn nor soybean was fully rotated. If we project that all continuous corn and continuous soybeans are rotated by 2051-2070, county-average corn yields will increase by 0.265 t/ha under SSP 1-2.6 and 0.164 t/ha under SSP 5-8.5, while county-average soybean yields will gain 0.064 t/ha under SSP 1-2.6 and 0.076 t/ha under SSP 5-8.5. These findings highlight the effectiveness of crop rotation in the face of warming NGS and GS in the future and can help evaluate opportunities for adaptation.