Soybean Yield Research Articles

Effect of Enriched Coconut Shell Biochar on Soil Properties and Soybean (Glycine max L.) Yield in Acidic Soils of Eastern Dry Zone of Karnataka, India

A two-season field study was conducted at ICAR-KVK, Hadonahalli, which is located in the Eastern Dry Zone of Karnataka, to evaluate the influence of phosphorus-solubilizing bacteria (PSB) and zinc-enriched coconut shell biochar on soil biological properties, nutrient bioavailability and soybean (Glycine max L.) yield in acidic soils. 13 treatments, including a control, package of practice and various combinations of PSB and zinc-enriched biochar were assessed in randomised complete block design at P=0.05 level of significance. The biochar was characterized for its physical properties, including bulk density (0.38 Mg m-3), water holding capacity (76.27%) and chemical properties including pH (9.52), electrical conductivity (1.12 dS m-1) and nutrient composition. Results indicated significant improvements in soil dehydrogenase activity, phosphatase activity and major nutrient bioavailability (N, P, K and Zn) in treatments receiving 100% NPK, PSB enriched FYM at 3.125 t ha-1 and different doses of zinc enriched Biochar at 5 t ha-1 compared to the control and package of practice. Soybean yield was maximized under treatments combining PSB-enriched FYM and zinc-enriched biochar, with the highest yield observed in T6 (23.61 q ha-1). The enhanced yield was attributed to improved soil health and nutrient dynamics by PSB and biochar. These findings underscore the potential of PSB and zinc-enriched biochar as sustainable amendments for enhancing soil fertility, crop productivity, and nutrient use efficiency in acidic soils.

Agronomic Efficiency of Compost Extracts and Nitrogen-Fixing Bacteria in Soybean Crops

Regenerative agriculture and the use of bioinputs have been gaining prominence in the global agribusiness sector, driven by the growing demand for healthier foods produced with minimal impact on ecosystems. In this context, compost and its derivatives (compost extracts and teas) are used to provide effective microorganisms to crops, although production processes affect the efficiency of compost extracts, as well as the soil microbiota. Thus, the hypothesis raised was that the organic matter source used for compost formation affects the agronomic efficiency of compost extracts. The objective of this study was to evaluate the effect of compost extracts based on litterfall of angiosperm (AC) and gymnosperm (GC) species, and the use of inoculation with the nitrogen-fixing bacteria Bradyrhizobium japonicum and Azospirillum brasilense (Bra+Azo), on soil quality, crop growth, grain yield, and disease control in soybean (Glycine max L.) crops. Using AC and GC resulted in varying effects on soybean growth and soil microbial biomass carbon (SMBC), confirming the hypothesis that the organic matter source affects the agronomic efficiency of compost extracts. Plants inoculated with Bra+Azo exhibited higher chlorophyll contents, resulting in a higher photochemical yield than for those treated with compost extracts (AC and GC). However, plants inoculated with AC and GC exhibited high plasticity in mitigating photochemical stress, reaching similar photosynthetic and transpiration rates to those observed in plants inoculated with Bra+Azo. Additionally, inoculation with Bra+Azo, overall, improved the photosynthetic efficiency of soybean plants, and the compost extracts (AC and GC) were more effective than the inoculation with Bra+Azo in increasing soybean 1000-grain weight, probably due to improvements in root development. The growth promotion observed with AC and GC is likely attributed to increases in SMBC by these compounds, denoting improvements in soil quality and biocontrol of damage caused by insect attacks.

Foliar application of iron strengthened- artificial humic acid promotes nitrogen fixation and improves soybean yield

Foliar application of iron strengthened- artificial humic acid promotes nitrogen fixation and improves soybean yield

Pulsating Drought and Insect Herbivory Cause Differential Effects on Soybean (Glycine max) Genotypes That Vary in Canopy Wilting Speed.

As a result of climate change, global temperatures are increasing, and water scarcity is on the rise. Soybean [Glycine max (L.) Merr] is one of the most important crops in the world due to its importance as food and feed. One of the major limiting factors for soybean production is drought, which can cause up to 80% reduction in yield. Therefore, growers and plant breeders are turning to soybean accessions that demonstrate better water use efficiency (WUE). However, in addition to drought, insect herbivory by soybean looper (Chrysodeixis includens, SBL) and fall armyworm (Spodoptera frugiperda, FAW) can also reduce soybean yield by feeding on foliar and floral organs. Using soybean accessions that differ in their wilting speed, we examined the relationship between physiological traits associated with WUE, and how they affect both herbivore and host plant growth and development. Results showed that both fast- and slow-wilting genotypes displayed strong overcompensation in terms of growth and development, but slow-wilting genotypes produced higher-quality pods and seeds. Regardless of treatment effects, FAW fed at a significantly higher rate than SBL despite being less specialized to feed on soybeans. While fast-wilting plants produced more pods than slow-wilting plants regardless of treatment, slow-wilting plants produced heavier pods with larger and heavier seeds. Collectively, we show that despite fast-wilting plants overcompensating in pod production and growth traits, slow-wilting plants may still be better fit through seed functions.

Deciphering the Dynamic Interplay between Rhizobacteria and Root Exudates via Cerium Oxide Nanomaterials Modulation for Promoting Soybean Yield and Quality.

The interplay between root exudates and rhizobacteria is essential for enhancing agricultural productivity. Herein, the impacts of cerium dioxide nanomaterials (CeO2 NMs) on these interactions in soybean plants were investigated. Following 3-5 weeks of exposure to 5 mg·kg-1 CeO2 NMs, the composition of root exudates changed over time, with isoflavone levels increasing by 6.3-21.7 folds, potentially manipulating the rhizobacteria. Correspondingly, rhizobacteria such as Ensifer, Allorhizobium, Nitrospira, and Bradyrhizobium were enriched by 40.7-367.3% at three time points. CeO2 NMs stimulated isoflavone biosynthesis in soybean plants and their excretion into the rhizosphere via upregulating the expressions of MYB transcription factors, biosynthesis, and transporter genes. The interactions of root exudates and rhizobacteria mediated by CeO2 NMs enhanced plant biomass (45.5-75.9%), nodulation (85.7%), nitrogen fixation, nutrient acquisition, and soil health, improving soybean quality (34.4-223.9%) and yield (16.2%). This study provides insights into root exudate-rhizobacteria interactions in leguminous plants facilitated by NMs for sustainable agriculture.

Effect of Different Application Methods of Iron Chelate (EDDHA Na Fe) on Agronomic, Yield, and Quality Characteristics of Soybean (Glycine Max (L.) Merr.)

ABSTRACT Soybeans are significantly affected by iron deficiency, a prominent type of abiotic stress that results in considerable yield losses. Various sources of iron are utilized to mitigate the adverse consequences of iron (Fe) deficiency. The success of Fe can vary depending on the application method and the stage of treatment. The research purpose of this study was to focus on various application methods, including soil, seed, and foliar application (two trifoliate vegetative stage-V2, five trifoliate vegetative stage-V5, and V2 + V5 stages) with iron chelate Iron(III) ethylenediamine-N,N’-bis(2-hydroxyphenylacetic acid) (FeEDDHA) fertilizer in a Fe deficiency susceptible soybean cultivar (cultivar Nova). After conducting a thorough analysis, it was concluded that applying FeEDDHA fertilizer as a foliar spray during V2, V5, and V2 + V5 resulted in better outcomes than using the seed and soil application methods. In the study, it was observed that the foliar treatment at V5 stage yielded the highest values for Soil Plant Analysis Development (SPAD index) (41.6), plant height (33.4 cm), number of nodes per plant (9.62), number of pods per plant (20.35), number of seeds per plant (22.75), and seed yield per plant (7.02). However, the highest values for oil (22.83%) and protein contents (38%) were obtained through the foliar Fe fertilization at V2 + V5 stages. The primary contribution of this study will lead to gain insightful knowledge about different methods of applying Fe fertilizers on soybean.

Salt Tolerance Induced by Plant Growth-Promoting Rhizobacteria Is Associated with Modulations of the Photosynthetic Characteristics, Antioxidant System, and Rhizosphere Microbial Diversity in Soybean (Glycine max (L.) Merr.)

Salinity stress poses a major obstacle to agricultural productivity. Employing plant growth-promoting rhizobacteria (PGPR) has attracted significant attention due to its potential to improve plant development in challenging conditions. Yet, additional investigation is essential to fully understand the potential of PGPR in mitigating salinity stress, especially in field applications. Hence, this study investigated the resistance mechanisms of soybean (Glycine max (L.) Merr.) under salt stress with PGPR application through a field experiment with four treatments: normal soybean planting (NN), normal planting + PGPR (NP), salt stress planting (SN), and salt stress planting + PGPR (SP). This research investigated how applying PGPR under salt stress influences soybean photosynthetic traits, osmotic regulation, rhizosphere microbial communities, and yield quality. The results demonstrated that salt stress enhanced leaf temperature and significantly reduced the leaf area index, SPAD value, stomatal conductance, photosynthetic rate, and transpiration rate of soybeans. Compared to SN treatment, SP treatment significantly improved the stomatal conductance, photosynthetic rate, and transpiration rate by 10.98%, 16.28%, and 35.59%, respectively. Salt stress substantially increased sodium (Na+) concentration and Na+/K+ ratio in leaves, roots, and grains while reducing potassium (K+) concentration in roots and leaves. Under salinity stress, PGPR application significantly minimized Na+ concentration in leaves and enhanced K⁺ concentration in leaves, roots, and grains by 47.05%, 25.72%, and 14.48%, respectively. PGPR application boosted carbon assimilation (starch synthesis) by enhancing the activities of sucrose synthase, fructokinase, and ADP-glucose pyrophosphorylase. It improved physiological parameters and increased soybean yield by 32.57% compared to SN treatment. Additionally, PGPR enhanced antioxidant enzyme activities, including glutathione reductase, peroxidase, ascorbate peroxidase, and monodehydroascorbate reductase, reducing oxidative damage from salt stress. Analysis of rhizosphere microbial communities revealed that PGPR application enriched beneficial bacterial phyla such as Bacteroidetes, Firmicutes, Nitrospirae, and Patescibacteria and fungal genera like Metarhizium. These microbial shifts likely contributed to improved nutrient cycling and plant–microbe interactions, further enhancing soybean resilience to salinity. This study demonstrates that PGPR enhances soybean growth, microbial diversity, and salt tolerance under salinity stress, while future efforts should optimize formulations, explore synergies, and scale up for sustainable productivity.

Analysis of Spatial Dependence Using the Wave Covariance Structure in Soybean Productivity Associated With Soil Attributes

Objective: The aim of this study is to investigate the interaction between soybean yield and the physical and chemical attributes of the soil, with the goal of developing techniques used in precision agriculture to increase productivity, reduce costs, and minimize environmental impacts. Theoretical Framework: This work is based on the principles of geostatistics, particularly the Wave spatial dependence structure, which is used to model the semivariance function when it exhibits the "hole effect." Method: The research involves a study of soybean yield conducted in a commercial area of 172.04 hectares during the 2022/2023 growing season. Calcium (Ca), copper (Cu), acidity (pH), potassium (K), phosphorus (P), and soil penetration resistance (SPR) levels were used as covariates to explain soybean yield (Prod) through a Gaussian linear spatial model (GLSM). The Thin Plate Spline (TPS) interpolation method was applied to interpolate the physical and chemical soil attributes, considered as fixed covariates, while soybean yield was interpolated using External Drift Kriging (EDK) based on the GLSM. Additionally, techniques for local influence diagnostics were developed and applied to identify observations impacting the results, utilizing the Wave geostatistical model. Results and Discussion: The results revealed that the generated soybean yield map provides important information for defining management zones, optimizing input use, and promoting greater profitability. Furthermore, the removal of locally influential observations alters parameter estimation, the significance of parameters associated with the covariates in the GLSM, and the construction of the interpolated soybean yield map. In the discussion, the results were contextualized in light of the theoretical framework, emphasizing the relevance of the Wave structure and the integration of interpolation techniques in the study of spatial variability. Research Implications: The practical and theoretical implications of this research include improvements in agricultural management by providing support for the delineation of management zones that balance productivity and sustainability. Theoretically, the study contributes to advancing the use of geostatistical models, such as the Wave model, in the analysis of spatial data in precision agriculture. Originality/Value: This study contributes to the literature by exploring the application of the Wave model in an agricultural context, combined with the use of interpolation techniques and local influence diagnostics. Its originality lies in the methodological combination of spatial interpolators and the development of local influence techniques.

Identification and functional characterization of the MYB transcription factor GmMYBLJ in soybean leaf senescence

Leaf senescence is an important agronomic trait that significantly influences the quality and yield of soybeans. v-Myb avian myeloblastosis viral oncogene homolog (MYB) transcription factors are considered crucial regulators governing leaf senescence, which can be utilized to improve agronomic traits in crops. However, our knowledge regarding the functional roles of soybean MYBs in leaf senescence is extremely limited. In this study, GmMYBLJ, a CCA1-like MYB, was identified and functionally characterized with respect to leaf senescence. The GmMYBLJ protein is localized in the nucleus, and a high accumulation of its transcripts was observed in nodules and embryos. Notably, GmMYBLJ was highly expressed in soybean senescent leaves and was transcriptionally induced by dark or NaCl treatment, as confirmed by histochemical GUS staining analysis. Ectopic overexpression of GmMYBLJ in Arabidopsis not only led to earlier leaf senescence, reduced chlorophyll content, and increased MDA accumulation but also promoted the expression of several WRKY family transcription factors and senescence-associated genes, such as SAG12 and ORE1. Further investigation showed that overexpression of GmMYBLJ accelerated Arabidopsis leaf senescence under darkness and in response to Pst DC3000 infection. Moreover, transgenic soybean plants overexpressing GmMYBLJ grew faster and exhibited accelerated senescence under salt stress. DAB staining analysis showed that GmMYBLJ induced ROS accumulation in soybean hairy roots and Arabidopsis leaves. Collectively, our results provided useful information into the functional roles of GmMYBLJ in both age-dependent and stress-induced senescence.

A Phosphate-Starvation Enhanced Purple Acid Phosphatase, GmPAP23 Mediates Intracellular Phosphorus Recycling and Yield in Soybean.

Plant internal phosphorus (P) recycling is a complex process, which is vital for improving plant P use efficiency. However, the mechanisms underlying phosphate (Pi) release from internal organic-P form remains to be deciphered in crops. Here, we functionally characterised a Pi-starvation responsive purple acid phosphatase (PAP), GmPAP23 in soybean (Glycine max). GmPAP23 could hydrolyse a series of Pi-containing compounds in vitro, such as trehalose-6-phosphate and glucose-l-phosphate. Moreover, GmPAP23 overexpression led to less P distribution in soybean source organs, including mature leaves and pod shells, but more P distribution in seeds under P sufficient conditions, although no effect was observed for transgenic soybean lines with its suppression. Metabolomic analysis found that a group of P-containing metabolites exhibited differential accumulations in mature leaves between wild type (WT) and GmPAP23 overexpression lines, such as glucose-l-phosphate and trehalose-6-phosphate. Moreover, a MYB transcription factor, GmPHR14 was subsequently found to activate the transcription of GmPAP23 via directly binding to its promoter. Collectively, these findings could highlight that the GmPHR14-GmPAP23 pathway, which controls internal P recycling in soybean, and thus affect yield.

Natural variation in the GmVPE1 promoter contributes to phosphorus re-translocation to seeds and improves soybean yield.

Phosphorus (P) is an essential yet frequently deficient plant nutrient. Optimizing P distribution and recycling between tissues is vital for improving P utilization efficiency (PUE). Yet, the mechanisms underlying the transport and re-translocation of P within plants remain unclear. Here, wide-ranging natural diversity in seed P allocation and positive correlations among yield traits were found using 190 soybean accessions in field trials. Among them, the P-efficient genotype BX10 outperformed BD2 in assessments of PUE that were largely explained through differences in P redistribution from pods to seeds under low P stress. Pods of BX10 were therefore subjected to transcriptome analysis, and GmVPE1 was identified as a vacuolar Pi transporter to investigate further. Importantly, significant DNA polymorphism in GmVPE1 promoter regions was remarkably associated with seed weight among soybean accessions grown on P-deficient soils. Further analyses suggested that mRNA abundance of GmVPE1 in haplotype 2 (Hap) is significantly higher than that GmVPE1Hap1. GmVPE1 was highly upregulated by P deficiency and preferentially expressed in pods, seeds, and seed coats, which was consistent with GUS staining using transgenic soybean plants carrying pGmVPE1Hap2::GUS. Near-isogenic lines carrying the GmVPE1Hap2 allele, along with stable transgenic soybeans overexpressing GmVPE1 in a GmVPE1Hap1 background, had increases in PUE, more seed setting, and greater yields in both greenhouse and field trials than control plants. In summary, natural variation among GmVPE1 alleles determines genetic expression and subsequent P re-translocation phenotypes, which impacts PUE and yield, and thereby makes this an important genetic resource for soybean molecular breeding.

Postemergence giant ragweed management as affected by soil and cover crop management, soybean planting time, and preemergence herbicide application

Abstract Early soybean planting and cover crop adoption in the US Midwest prompt investigation into the impact of these practices on weed community dynamics and best management practices. While previous research has explored different aspects of giant ragweed control, the specific integration among soil management practices, including cover crop adoption, soybean planting timing, and herbicide use, has not been thoroughly investigated. This study assessed soil management, soybean planting time, and PRE herbicide application on giant ragweed control and soybean yield in Wisconsin and Nebraska in 2022 and 2023. The study included a factorial arrangement of four soil management treatments [conventional tillage, no-till, and fall-planted cereal rye early terminated and terminated at planting (planting green)]; two soybean planting times; and two PRE herbicide treatments (PRE and no PRE). Postemergence (POST) herbicides were applied when ∼50% of giant ragweed plants within each treatment reached ∼10 cm in height. In Nebraska, cereal rye and tillage treatments without a PRE had at least 67% lower giant ragweed density than no-till at POST. In no-till, densities were at least 60% lower with PRE compared to no PRE. In Wisconsin, cereal rye did not reduce giant ragweed density at POST compared to no-till, likely due to relatively low biomass accumulation. In contrast, delayed soybean planting reduced giant ragweed density for most treatments but lowered soybean yield in no-till and planting green treatments. The PRE herbicides had either no or positive effects on reducing giant ragweed density and increasing soybean yield. Overall, this study suggests that soil management and soybean planting timing are crucial for effective giant ragweed management in Wisconsin, where biotypes with a long emergence window during the spring and summer are present, while in Nebraska, soil management and soybean planting timing are less critical due to giant ragweed biotypes with an early and short emergence window in the spring.

Weed Management in Early Planted Soybean Early Planted Soybean Weed Management as Effected by Herbicide Application Rate and Timing

Abstract The opportunity to increase soybean yield has prompted Illinois farmers to plant soybean earlier than historical norms. Extending the growing season with an earlier planting date might alter the relationship between soybean growth and weed emergence timings, potentially altering the optimal herbicide application timings to minimize crop yield loss due to weed interference and ensure minimal weed seed production. The objective of this research was to examine various herbicide treatments applied at different timings and rates to assess the effect on weed control and yield in early planted soybean. Field experiments were conducted in 2021 at three locations across central Illinois to determine effective chemical strategies for weed management in early planted soybean. Preemergence (PRE) treatments consisted of a S-metolachlor plus metribuzin premix applied at planting or just prior to soybean emergence at 1/2x (883 + 210 g ai ha-1) or 1x (1,766 + 420 g ai ha-1) label recommended rates. Postemergence (POST) treatments were applied when weeds reached 10 cm tall and consisted of 1x rates of glufosinate (655 g ai ha-1) plus glyphosate (1,260 g ae ha-1) plus ammonium sulfate, with or without pyroxasulfone at a 1/2x (63 g ai ha-1) or 1x (126 g ai ha-1) rate. Treatments comprised of both a full rate of PRE followed by (fb) a POST resulted in the greatest and most consistent weed control at the final evaluation timing. The addition of pyroxasulfone to POST treatments did not consistently reduce late-season weed emergence. The lack of a consistent effect by pyroxasulfone could be attributed to suppression of weeds by soybean canopy closure due to earlier soybean development. The full rate of PRE extended the timing of POST application 2 to 3 weeks for all treatments at all locations except Urbana. Full-rate PRE treatments also reduced the time between the POST application and soybean canopy closure. Overall, a full rate PRE reduced early season weed interference and minimized soybean yield loss due to weed interference.

Analysis of the Synergistic Effect of Endophytic Bacteria and Metabolites on Yield in Soybean Roots Under Biochar with Nitrogen Fertilization

The appropriate application of nitrogen fertilizers and biochar to the soil is beneficial for soybean growth, and a combination of biochar and nitrogen can improve low-nitrogen fertilizer utilization efficiency. However, the effect of the combination of biochar and nitrogen fertilizer on soybean roots is still unclear. Therefore, in this study, we investigate the changes in endophytic bacterial communities and metabolites in soybean roots under different combinations of biochar and nitrogen fertilizer treatments by setting different fertilization levels and using high-throughput sequencing and non-targeted metabolomics techniques. The results showed that applying 20 t/ha of biochar and 180 kg/ha of nitrogen fertilizer (C2N1) resulted in the highest soybean yield. By studying the endophytic bacterial community in soybean roots, it was observed that the dominant phyla were Proteobacteria, Bacteroidota, and Actinobacteriota, and the dominant genera were Bradyrhizobium, Streptomyces, and Rhizobacter. Moreover, a metabolic pathway analysis revealed that glycosylphosphatidylinositol (GPI)-anchor biosynthesis was the most significant metabolic pathway in the C0N1 vs. C0N0 comparison group, and glycerophospholipid metabolism was the most significant metabolic pathway in the C2N1 vs. C1N1 comparison group; they were both associated with regulatory mechanisms such as plant growth promotion and nutrient cycling. Structural equation modeling indicates that both endophytic bacteria and metabolites have a significant positive impact on yield. Bradyrhizobium and Rhizobium are observable variables with significant positive effects on endophytic bacteria, while Phe-Thr and 7-allyloxycoumarin are observable variables with significant positive effects on metabolites. Endophytic bacteria not only have a direct impact on crop yield, but also indirectly affect crop yield through their effects on metabolites. This study has important scientific value and guiding significance for improving soybean yields.

Effects of Irrigation with Treated Slaughterhouse Effluent and Bradyrhizobium spp. Inoculation on Soybean Development and Productivity: Strategies for Sustainable Management

Water scarcity challenges in agriculture are prompting the exploration of alternative irrigation sources, including treated effluents. This study investigates the effects of irrigation with treated slaughterhouse effluent on soybean productivity and development, with and without inoculation, over two cropping cycles. Plant performance was significantly influenced by environmental factors and the interaction between effluent and inoculation. Plant height and leaf area were greater in the second cycle, with effluent enhancing growth and foliar development. Fresh and dry shoot biomass showed significant interactions among cycle, inoculation, and effluent, with higher effluent concentrations combined with inoculation being most effective in the first cycle. Foliar nitrogen concentrations were higher in the first cycle, particularly at elevated effluent doses, while foliar sodium showed a positive correlation with nitrogen and a negative correlation with magnesium. Chlorophyll indices varied across developmental stages, with maximum chlorophyll b estimated at 85.35% effluent irrigation. Soybean yield did not vary significantly with effluent dilutions, suggesting environmental factors had a greater influence. In conclusion, treated effluent irrigation represents a sustainable strategy for soybean production, optimizing water and nutrient use while reducing reliance on chemical fertilizers.

Effects of Different Intertillage Practices on Soil Biochemical Properties and Soybean Yield in Soybean Fields

Heilongjiang Province, China, is a major soybean-producing area where low temperatures in early spring and poor soil moisture retention are the main limiting factors leading to low soybean yields. To improve land productivity, this study was conducted in Heilongjiang Province, China, from 2020–2021 via a field plot trial method, where four different intertillage treatments were set up in 2020: conventional intertillage (T1), early intertillage (T2), conventional subsoiling (T3), and early subsoiling (T4). In 2021, the effects of intertillage on soil biochemical characteristics and soybean yield formation were systematically analyzed under the T5 treatment (subsoiling at the stage of full development from the fourth to the fifth compound leaf) and the T6 treatment (soil culture at the stage of full development from the fourth to the fifth compound leaf). The results of the experiment revealed that deep loosening in advance improved the chemical properties of the soil. Compared with those of the T1 treatment, the contents of the organic carbon, total nitrogen, and available phosphorus and potassium in the early subsoiling treatments (T4, T5, and T6) were significantly increased. Intertillage time and depth had a strong influence on the soil microbial characteristics. Early medium intertillage could significantly increase the species abundance of bacteria and fungi in the soil, whereas subsoiling could increase the relative abundance ratio and uniformity of the dominant species. Compared with that in the T1 treatment, the yield of soybean in the T4 treatment was significantly greater, with yield increases ranging from 18.71% to 19.36%. In summary, the intertillage measures of one deep loosening and one medium soil cultivation at the stage of full development from the fourth to the fifth compound leaf and one large soil cultivation at the stage of full development from the sixth to the seventh compound leaf can be adopted on the basis of early deep loosening 4–5 d after soybean sowing to achieve high soybean yields. The results provide a theoretical basis for increasing the yield and efficiency of soybean fields under corn–soybean rotation, as well as innovation and development of cultivation systems

Crop rotation and herbicide program effects on Palmer amaranth and common ragweed population growth rate

AbstractThe success of weed management decisions must be assessed not only in the short‐term within season but also in the long‐term over several seasons. This study investigated the effects of crop rotation and herbicide program structure on the population growth rates of Palmer amaranth (Amaranthus palmeri S. Watson) and common ragweed (Ambrosia artemisiifolia L.). A field experiment was conducted over a 3‐year period in North Carolina to compare cotton (Gossypium hirsutum L.)–sweetpotato [Ipomoea batatas (L.) Lam.]–soybean [Glycine max (L.) Merr.], cotton–peanut (Arachis hypogaea L.)–soybean, cotton–tobacco (Nicotiana tabacum L.)–soybean, and cotton–soybean–soybean rotations and preemergence and postemergence herbicide application timings. Results showed that preemergence herbicide application in the soybean phase of the rotation reduced Palmer amaranth populations 79%. However, the preemergence herbicides were only effective at reducing weed populations for the current season, not beyond. Common ragweed population growth rate was highest after the first 2 years (λ = 1.63) of the cotton–tobacco–soybean rotation. Preemergence herbicides were effective in reducing common ragweed populations, particularly in rotations with cotton–sweetpotato and cotton–peanut. Soybean yields were similar across rotations ranging from 62 bu/ac to 68 bu/ac. Annual use of preemergence herbicides was essential to reduce Palmer amaranth populations. For common ragweed, the effectiveness of preemergence herbicides to mitigate population growth was reduced when poorly competitive crops were part of the rotation.

Honey bee toxicity of pesticides used in United States maize and soybean production, 1998–2020

Abstract Pesticides are widely used around the world and have demonstrated benefits to crop production. However, pesticides have also been associated with negative impacts to non-target organisms, including pollinators. Here, we combined pesticide usage and toxicity data to create a toxicity index, which shows that pesticide hazard to honey bees (Apis mellifera) has changed substantially in U.S. maize (Zea mays) and soybean (Glycine max) production between 1998 and 2020. To reduce potential risks to honey bees and increase the eco-efficiency of crop production, efforts should be made to refine management strategies for pests that contribute most to the honey bee toxicity index. In maize, Coleoptera and Lepidoptera pests drive pesticide usage most responsible for hazard to honey bees, although the relative hazard from targeting those pests has decreased over time. In soybean, hemipteran pests were the largest relative contributor to insecticide honey bee hazard. Specific pests that contributed to honey bee toxicity hazard included corn rootworm species (Diabrotica spp.), silk-eating insects, and cutworms in maize, and stink bugs (Family Pentatomidae) and aphid species (Family Aphididae) in soybean. We combined crop yield data with the toxicity index to quantify the eco-efficiency, a measure of crop yield per unit of toxicity hazard. While crop yield for both maize and soybean increased steadily throughout the study period, eco-efficiency decreased in both crops between 2012 to 2020, suggesting increases in crop yield have failed to keep pace with increases in insecticide hazard to honey bees.

Response of Crop Yield and Productivity Contribution Rate to Long-Term Different Fertilization in Northeast of China.

To reveal the changes in crop yield and contribution rate of black soil productivity under long-term different fertilization conditions in black soil areas and to find the important significance of fertilization for sustainable and stable crop yield, high yield, and improving the contribution rate of black soil nutrients. Based on the long-term experiment of black soil fertility in Harbin, the Ministry of Agriculture and Rural Affairs, under the maize-wheat-soybean rotation system, crop yield, sustainability and stability of yield, the contribution rate of black soil productivity, and natural nutrient supply capacity under 10 fertilization treatments (CK, NP, NK, PK, NPK, M, MNP, MNK, MPK, and MNPK) were analyzed. Results showed that, compared with the treatment of chemical fertilizer, yields of maize, wheat, and soybeans increased under treatment of organic fertilizer combined with chemical fertilizer, among which the yields of maize and wheat changed the most. As the rotation period lengthened, the sustainable yield index (SYI) values of chemical fertilizer treatment and its combination with organic fertilizer treatment gradually decreased. During the rotation period, the SYI value follows: chemical fertilizer combined with organic fertilizer > chemical fertilizer > organic fertilizer. The coefficient of variation (CV) of yield stability showed an overall trend of increasing first and then decreasing, with individual treatments showing a gradual increasing trend (NP and NPK; MNP and MNPK). Under different rotation periods, the overall contribution rate of soil productivity of long-term organic fertilizer combined with chemical fertilizer treatment was higher than that of single chemical fertilizer treatment. With the extension of the rotation period, the contribution rate of soil productivity of NPK treatment was higher and slightly increased, while other treatments showed a downward trend. Although the contribution rate of soil productivity of organic-inorganic fertilizer combined treatment (MNP and MNK) showed a downward trend, it still remained at a high level (97.2% and 95.9%). In addition, the black soil has strong phosphorus and potassium supply capacity; nitrogen was lower than those two elements, with an average natural potassium supply capacity of 94.0-97.1%. Therefore, the combination of organic and inorganic fertilizers is one of the most effective fertilization measures to stabilize crop yield in the black soil region. Nitrogen fertilizer, as a limiting factor for crop growth in the black soil region, should be emphasized in its application.

Swift and portable detection of soybean mosaic virus SC7 through RNA extraction and loop-mediated isothermal amplification using lateral flow device.

The soybean mosaic disease-caused by the soybean mosaic virus (SMV)-significantly impacts soybean quality and yield. Among its various strains, SMV-SC7 is prevalent in China. Therefore, rapid and accurate diagnosis is deemed critical to mitigate the spread of SMV-SC7. In this study, a simple and rapid magnetic bead-based RNA extraction method was optimized. Furthermore, a reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay that requires no specialized equipment such as PCR Amplifier was proposed, employing a lateral flow device (LFD) for visual interpretation of SMV-SC7. The RT-LAMP-LFD approach facilitated specificity testing of SMV-SC7. Moreover, the limit of detection (LOD) of this method was as low as 10-5 ng (2.4 copies). The sensitivity of RT-LAMP-LFD was 10-fold higher than that of the colorimetric RT-LAMP method. In 194 field samples tested, the RT-LAMP-LFD detection of the SMV-SC7 had accuracy of 98.45% in comparison to RT-qPCR. In conclusion, the assay exhibited high specificity, sensitivity, and rapidity, enabling economical and portable detection of SMV-SC7 and providing technical support to identify SMV-SC7-infected soybeans.