Soybean Research Articles

Bacillus amyloliquefaciens SS1-fermented soybean meal influenced the flesh texture of Nile tilapia: Involvement of microbial metabolite propionate

Microbial fermentation is recognized to improve feed utilization and health of farmed animals. However, its effect on flesh quality and the underlying mechanisms remain understudied. Herein, Bacillus amyloliquefaciens SS1, a probiotic strain isolated from the intestinal tract of Nile tilapia (Oreochromis niloticus) was used to ferment soybean meal (FSM). Two tilapia experimental diets containing FSM and raw soybean meal were formulated for an eight-week feeding trial. Results showed that dietary FSM significantly increased the carcass ratio of fish, while there was no significant difference in weight gain or feed utilization between the two dietary treatments. Texture profile analysis showed that muscle springiness was improved by the FSM diet. There was no discernible difference in myofiber morphology between the two treatments. However, the FSM-fed fish had significantly lower muscle lipid contents than the control, accompanied by suppressed lipogenesis, while lipolysis was promoted both in muscle and liver tissues. Interestingly, the FSM diet modified gut microbial community, resulting in increased propionate concentrations. By establishing a high-fat model using primary hepatocytes of tilapia, we demonstrated the role of propionate in reducing lipid accumulation. Our finding highlights the emerging roles of gut-derived metabolites in affecting flesh quality by modifying host metabolism, providing a foundation for improving the flesh quality of aquaculture fish starting from the feed.

Developing Adventitious Root Meristems Induced by Layering for Plant Chromosome Preparation

Chromosome numbers and morphology are important characteristics of a species and its evolution. Root tips are the most commonly used tissue as a source of actively dividing cells for chromosome visualization in plants. Previously, rapidly growing root tips were collected from germinating kernels or from seedlings growing in pots or fields. However, the use of adventitious roots (ARs) derived from aerial tissue as meristems for chromosome visualization has always been overlooked. Here, we successfully induced ARs in 11 materials that were investigated, with the exception of Sorghum nitidum. Using ARs meristem we obtained high-quality chromosome spreads for Morus alba, Broussonetia papyrifera, Lolium multiflorum, Sorghum sudanense, S. propinquum, S. bicolor × S. sudanense, Zea mays, Z. mexicana, Glycine max, Medicago sativa, and Brassica napus. The results reported here demonstrate that layering is an alternative and effective method for producing meristematic cells for high-quality chromosome preparation in plant species producing ARs. For species that produce ARs by layering, this protocol is particularly valuable for the development of cost-effective and high-throughput non-invasive cytogenetic studies.

Economic considerations of in‐season potassium applications to soybean using payoff matrices

AbstractPotassium (K) deficiency is a common yield‐limiting factor in Arkansas soybean (Glycine max (L.) Merr.) production that can be addressed with innovative supplemental fertilizer application. An established leaf sampling protocol and dynamic critical concentration allow accurate diagnosis of K deficiency with corresponding recommendations for corrective, in‐season K fertilizer applications at site‐specific rates and times to reach anticipated yield goals. However, the profitability of in‐season K fertilizer applications to irrigated soybean remains unclear. Research was conducted in Arkansas from 2021 to 2023 to evaluate multiple rates of in‐season applications of muriate of potash to soybean at 15 and 30 days after first flower (DAR1). The economic ramifications of in‐season fertilizer applications were quantified by calculating yield averages, partial returns (PRs), and regret when comparing PR to not fertilizing, each assuming 5‐year average prices for fertilizer and soybean grain. Significant yield responses to in‐season potash fertilizer were found at both 15 and 30 DAR1 times. These yield increases translated to large increases in PR or lower regret when compared to using no fertilizer. Corrective applications of 74–112 kg K ha−1 were often considered optimal, with risk assessments provided to allow informed decisions. Results were summarized by category of leaf‐K concentration, and treatment averages were provided to calculate payoff matrices for 15 and 30 DAR1 times. The resulting payoff matrices can be used as a decision support tool with any grain and fertilizer price to facilitate informed management decisions that optimize profitability as soybean and fertilizer prices impact optimal outcomes.

Dynamics of legume Cropping and Agro-ecological Transition in the Cotton Savannah Zones of West Africa: the Case of Koumbia District of Burkina Faso

Aims: This paper shows the contribution of participatory research to upgrade the integration of legumes into cropping systems. Place and Duration of Study: The investigation is based on survey data collected in 2008 and 2011 (two reference years) and 2021 and 2022 (current situation) in the village of Koumbia in western Burkina Faso. Methodology: Data was collected through surveys and field measurements. The surveys were conducted with a sample of fifty (50) volunteer farmers. In 2008, 2011 and 2022, the same questionnaire was administered to all 50 farmers. Field measurements with GPS (Global Positioning System) were conducted on crop area. Results: The results show that the proportion of area under legumes crops increased by 77,38% after 15 years. Other legumes crops (Glycine max and Mucuna sp.) were introduced in addition to those previously grown (groundnuts and cowpeas) by farmers. Surface cropped in sorghum (35.36%) and millet (82.79%) declined while cotton and maize remain the main crops in the zone. The results on farmers’ perception show that they prefer single cropping of legume crops as their insertion modality in the existing farming systems compared to their association with cereals. Conclusion: The study shows that the role of legumes is increasing in the cropping system, and represents an opportunity to succeed in the agro-ecological transition, even though the intercropping of cereal/legume, which is put forward by the theoretical models of the agro-ecological transition, is still little practiced. The structuration of the legume sector can be a condition for achieving it.

Advances in Soybean Genetic Improvement

The soybean (Glycine max) is a globally important crop due to its high protein and oil content, which serves as a key resource for human and animal nutrition, as well as bioenergy production. This review assesses recent advancements in soybean genetic improvement by conducting an extensive literature analysis focusing on enhancing resistance to biotic and abiotic stresses, improving nutritional profiles, and optimizing yield. We also describe the progress in breeding techniques, including traditional approaches, marker-assisted selection, and biotechnological innovations such as genetic engineering and genome editing. The development of transgenic soybean cultivars through Agrobacterium-mediated transformation and biolistic methods aims to introduce traits such as herbicide resistance, pest tolerance, and improved oil composition. However, challenges remain, particularly with respect to genotype recalcitrance to transformation, plant regeneration, and regulatory hurdles. In addition, we examined how wild soybean germplasm and polyploidy contribute to expanding genetic diversity as well as the influence of epigenetic processes and microbiome on stress tolerance. These genetic innovations are crucial for addressing the increasing global demand for soybeans, while mitigating the effects of climate change and environmental stressors. The integration of molecular breeding strategies with sustainable agricultural practices offers a pathway for developing more resilient and productive soybean varieties, thereby contributing to global food security and agricultural sustainability.

High barley intake in non-obese individuals is associated with high natto consumption and abundance of butyrate-producing bacteria in the gut: a cross-sectional study

ObjectiveBarley, abundant in β-glucan, a soluble dietary fiber, holds promise in obesity prevention. Given the microbial metabolism of dietary fiber in the gastrointestinal tract, we investigated the role of gut microbiota in non-obese individuals consuming high levels of barley.MethodsOur study enrolled 185 participants from “The cohort study on barley and the intestinal environment (UMIN000033479).” Comprehensive physical examinations, including blood tests, were conducted, along with separate assessments of gut microbiome profiling and dietary intake. Participants were categorized into high and low barley consumption groups based on the median intake, with non-obese individuals in the high intake group identified as barley responders while participants with obesity were designated as non-responders. We compared the relative abundance of intestinal bacteria between these groups and used multivariate analysis to assess the association between intestinal bacteria and barley responders while controlling for confounding factors.Results and discussionAmong the fermented food choices, responders exhibited notably higher consumption of natto (fermented soybeans) than non-responders. Moreover, after adjusting for confounders, Butyricicoccus and Subdoligranulum were found to be significantly more prevalent in the intestines of responders. Given natto’s inclusion of Bacillus subtilis, a glycolytic bacterium, and the butyrate-producing capabilities of Butyricicoccus and Subdoligranulum, it is hypothesized that fiber degradation and butyrate production are likely to be enhanced within the digestive tract of barley responders.

Confirmation of Glyphosate Resistance in Annual Bluegrass (Poa annua) via EPSPS Duplication in a Soybean and Rice Rotation

Abstract Annual bluegrass (Poa annua L.) populations in turfgrass have evolved resistance to several herbicides in the United States (US), but there has been no confirmed resistance from an agricultural field. Recently, glyphosate failed to control a P. annua population found in a field in a soybean [(Glycine max (L.) Merr.] and rice (Oryza sativa L.) rotation in Poinsett County, Arkansas. The present study focused on determining the sensitivity of a putatively-resistant accession (R1) to glyphosate compared with two susceptible accessions (S1 and S2). The experiments included a dose-response study, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene copy number and expression analysis, and assessment of mutations in EPSPS. Based on the dose-response analysis, R1 required 1,038 g ae ha-1 of glyphosate to cause 50% biomass reduction, whereas S1 and S2 only required 148.2 g and 145.5 g ae ha-1, respectively. The resistant index (RI) was approximately 7-fold relative to the susceptible accessions. Real-time polymerase chain reaction data revealed at least a 15-fold increase in the EPSPS copy number in R1, along with a higher gene expression. No mutations in EPSPS were found. Gene duplication was identified as the main mechanism conferring resistance in R1. The research presented here reports the first incidence of glyphosate resistance in P. annua from an agronomic field crop situation in the US.

Sensitivity of soybean (Glycine max L.) pathogens Diaporthe aspalathi, D. caulivora, and D. longicolla to Difenoconazole and Fluopyram fungicides

Diseases of soybean (Glycine max L.) caused by species of Diaporthe have resulted in estimated yield losses totaling $248.2 million in the U.S. over the past 10 years. To effectively manage species of Diaporthe, it is important to use an integrated approach. In this study, we evaluated the in vitro sensitivity of isolates of the soybean pathogens Diaporthe aspalathi, D. caulivora, and D. longicolla from 18 U.S. states to difenoconazole (a demethylation inhibitor fungicide) and fluopyram (a succinate dehydrogenase inhibitor fungicide). The fungicides were incorporated into 2% water agar (WA) in petri dishes at various concentrations. A mycelial plug of each isolate (n=59 for difenoconazole and n=55 for fluopyram) obtained from a 7-day-old culture was placed at the center of the WA and incubated in the dark. After five days for D. caulivora and D. longicolla, and eight days for D. aspalathi, the colony diameter was measured, and the corresponding percent inhibition and effective concentration at which 50% mycelial growth was inhibited (EC50) were determined. Significant differences in EC50 values (P<0.0001) were observed among the isolates of D. aspalathi (0.227 µg/ml), D. caulivora (0.130 µg/ml), and D. longicolla (1.860 µg/ml) for difenoconazole. Similarly, for fluopyram, the EC50 values varied significantly (P<0.001) among the D. aspalathi (2.233 µg/ml), D. caulivora (1.610 µg/ml), and D. longicolla (0.347 µg/ml) isolates. This study established sensitivity profiles for difenoconazole and fluopyram fungicides for D. aspalathi, D. caulivora, and D. longicolla, and provides valuable information that may help in the development of Diaporthe disease management program.

TRANSCRIPTIONAL ANALYSIS OF SOYBEAN (Glycine max) GENES RELATED TO WATER DEFICIT

ABSTRACT The soybean crop has been gaining worldwide prominence, being widely disseminated due to its various forms of use in different segments. Genetic and environmental factors are decisive in the quality of this culture. A feature related to the environmental factor that has gained prominence is the water deficit. Molecular events are initiated by the perception of water stress, involving a complex genetic network. Studies in recent decades have already identified some genes related to water stress in plants, it is known that the dehydration-responsive element binding protein (DREB) plays an important role in the response to water deficit. Therefore, this work aimed to analyze the expression of genes related to water deficit in soybean. For the analysis of gene expression, leaves of soybean (Glycine max (L.) Merrill), cultivar M9144 RR, submitted to the following treatments were used: 25V25R – plants subjected to water deficit throughout the cycle, being irrigated with 25% of ETpc and 100V100R – plants that did not experience water deficit, being irrigated with 100% of ETpc throughout the cycle. The quantification of the relative expression of the genes GmDREB1 and GmDREB5 showed that the water stress suffered by the cultivar was greater in the reproductive stage. Keywords: Transcription factors, development stages, gene expression.

Exploring Black Soybean Extract Cream for Inflammatory Dermatitis—Toward Radiation Dermatitis Relief

We aimed to evaluate the effect of black soybean extract cream (BSEC) on 2,4-dinitrochlorobenzene (DNCB)-induced dermatitis in murine models mimicking inflammatory dermatitis observed in humans. In this DNCB-induced model, BALB/c mice were spread with 100 μL of 2% DNCB twice a week for two weeks to induce skin inflammation on the shaved back skin; then, a placebo or BSEC that consisted of the volatile fraction derived from the seeds of Glycine max (L.) Merr. was applied to the DNCB-sensitized mice for 7 days. Gross visual analysis was conducted to assess the impact of BSEC on dermatitis, and an enzyme-linked immunosorbent assay (ELISA) was subsequently performed to detect inflammatory cytokines in the presence or absence of BSEC after DNCB sensitization. Lastly, the possible mechanisms responsible for the effects of BSEC on inflammatory dermatitis were investigated in a human leukemia monocytic cell line, THP-1. Our study showed that BSEC displayed antioxidant and anti-inflammatory effects. BSEC has the ability to diminish dermatitis, and all three experiments demonstrated that BSEC effectively reduced the progression of dermatitis while significantly suppressing inflammatory responses in the preclinical models. Consequently, BSEC exhibited promising phytotherapy for inflammatory dermatitis, potentially attributed to its anti-inflammatory and antioxidant properties.

Effect of center-pivot and subsurface drip irrigation systems on growth and evapotranspiration of volunteer corn in corn, soybean, and sorghum

Abstract Volunteer corn (Zea mays L.) is a competitive weed in corn-based cropping systems. Scientific literature does not exist about the water use of volunteer corn grown in different crops and irrigation systems. The objectives of this study were to characterize the growth and evapotranspiration (ETa) of volunteer corn in corn, soybean [Glycine max (L). Merr.], and sorghum [Sorghum bicolor (L.) Moench] under center-pivot irrigation (CPI) and subsurface drip irrigation (SDI) systems. Field experiments were conducted in south-central Nebraska in 2021 and 2022. Soil moisture sensors were installed at depths of 0 to 0.30, 0.30 to 0.60, and 0.60 to 0.90 m to track soil water balance and quantify seasonal total ETa. Corn was the most competitive, as volunteer corn had the lowest biomass, leaf area, and plant height compared with the fallow. Soybean was the least competitive with volunteer corn, as the plant height, biomass, and leaf area of volunteer corn in soybean were similar to fallow at 15, 30, 45, and 60 d after transplanting (DATr). Averaged across crop treatments, irrigation type did not affect volunteer corn growth at 15 to 45 DATr. Soil water depletion and ETa were similar across crop treatments with and without volunteer corn, as water was not a limiting factor in this study. The ETa of volunteer corn was the highest in soybean (623 mm), followed by sorghum (622 mm), and corn (617 mm) under CPI. The SDI had higher irrigation efficiency, because without affecting crop yield, it had 3%, 6%, and 8% lower ETa in soybean (605 mm), sorghum (585 mm), and corn (571 mm), respectively. Although soil water use did not differ with volunteer corn infestation, a soybean yield loss of 27% was observed, which suggests that volunteer corn may not compete for moisture under fully irrigated conditions; however, it can impact the crop yield potential due to competition for factors other than soil moisture.

Methods to optimize optical sensing of biotic plant stress – combined effects of hyperspectral imaging at night and spatial binning

In spatio-temporal plant monitoring, optical sensing (including hyperspectral imaging), is being deployed to, non-invasively, detect and diagnose plant responses to abiotic and biotic stressors. Early and accurate detection and diagnosis of stressors are key objectives. Level of radiometric repeatability of optical sensing data and ability to accurately detect and diagnose biotic stress are inversely correlated. Accordingly, it may be argued that one of the most significant frontiers and challenges regarding widespread adoption of optical sensing in plant research and crop production hinges on methods to maximize radiometric repeatability. In this study, we acquired hyperspectral optical sensing data at noon and midnight from soybean (Glycine max) and coleus wizard velvet red (Solenostemon scutellarioides) plants with/without experimentally infestation of two-spotted spider mites (Tetranychus urticae). We addressed three questions related to optimization of radiometric repeatability: (1) are reflectance-based plant responses affected by time of optical sensing? (2) if so, are plant responses to two-spotted spider mite infestations (biotic stressor) more pronounced at midnight versus at noon? (3) Is detection of biotic stress enhanced by spatial binning (smoothing) of hyperspectral imaging data? Results from this study provide insight into calculations of radiometric repeatability. Results strongly support claims that acquisition of optical sensing data to detect and characterize stress responses by plants to detect biotic stressors should be performed at night. Moreover, the combination of midnight imaging and spatial binning increased classification accuracies with 29% and 31% for soybean and coleus, respectively. Practical implications of these findings are discussed. Study results are relevant to virtually all applications of optical sensing to detect and diagnose abiotic and biotic stress responses by plants in both controlled environments and in outdoor crop production systems.

Morphophysiological variation, vigor test, and influence of light and temperature on the germination of four cultivars of Glycine max (L.) Merrill

Soybean (Glycine max. (L.) Merrill) is a crop whose productivity depends on the quality of the seeds used. In this context, the objective of this study was to characterize the seeds physically, evaluate viability using tetrazolium, identify physiological vigor through an electrical conductivity test, and determine the influence of temperature and photoperiod on the germination of four cultivars (Ultra, Olimpo, Extrema and Foco). 200 seeds were used, measuring size, weight of a thousand seeds, moisture content, and fresh mass. In tetrazolium (1%), 100 seeds were soaked for 4 h at 25°C. For electrical conductivity, 50 seeds were submerged on 75 mL of deionized water at 25°C for periods of 4, 8, 12, 16, 20 and 24 h. In the germination process, the treatments (four replications of 50 seeds) were incubated (B.O.D.) at temperatures of 25°C, 27°C, 30°C and 35°C, under photoperiods of 12 and 14 h. The experimental design adopted was completely randomized for all experiments, and the means were subjected to analysis of variance and Tukey's test at 5% probability. The Ultra cultivar presented perimeter (38.21±3.72 mm), length of 9.98±0.24 mm, and width of 7.94±0.27 mm. The cultivars presented viability above 90%. For electrical conductivity, the 12 h period was effective for identifying vigor. The Ultra cultivar (25°C and 12 h of photoperiod) achieved 77% germination, 10 germinated seeds per day, an average germination time of 4 days and 43 germinated seeds by the third day.

Confirmation of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) populations in New York and responses to alternative chemistries

Abstract Palmer amaranth (Amaranthus palmeri S. Watson, AMAPA) is one of the most troublesome weeds in North America due to its rapid growth rate, substantial seed production, competitiveness and the evolution of herbicide-resistant populations. Though frequently encountered in the South, Midwest, and Mid-Atlantic regions of the United States, A. palmeri was recently identified in soybean [Glycine max (L.) Merr.] fields in Genesee, Orange, and Steuben counties, NY, where glyphosate was the primary herbicide for in-crop weed control. This research, conducted in 2023, aimed to (1) describe the dose response of three putative resistant NY A. palmeri populations to glyphosate, (2) determine their mechanisms of resistance, and (3) assess their sensitivity to other postemergence herbicides commonly used in NY crop production systems. Based on the effective dose necessary to reduce aboveground biomass by 50% (ED50), the NY populations were 42 to 67 times more resistant to glyphosate compared with a glyphosate-susceptible population. Additionally, the NY populations had elevated EPSPS gene copy numbers ranging from 25 to 135 located within extrachromosomal circular DNA (eccDNA). Label rate applications of Weed Science Society of America (WSSA) Group 2 herbicides killed up to 42% of the NY populations of A. palmeri. Some variability was observed among populations in response to WSSA Group 5 and 27 herbicides. All populations were effectively controlled by labeled rates of herbicides belonging to WSSA Groups 4, 10, 14, and 22. Additional research is warranted to confirm whether NY populations have evolved multiple resistance to herbicides within other WSSA groups and to develop effective A. palmeri management strategies suitable for NY crop production.

Nutritional Supplement with Fermented Soy in Patients Under Active Surveillance for Low-Risk or Intermediate-Risk Prostate Cancer: Results from the PRAEMUNE Trial

Background/Objectives: To investigate the effect of a fermented soy supplement during 18 months in patients under active surveillance (AS) for low-risk and selected favorable intermediate-risk prostate cancer (PCa), with an emphasis on PSA modulation. Methods: Low-risk patients with ISUP grade 1, clinical stage cT1 or cT2a, PSA < 10 ng/mL and favorable intermediate-risk patients with ISUP grade 2 (<10% pattern 4), clinical stage T2b-c, PSA 10–20 ng/mL. The primary outcome was PSA response defined as maximum PSA rise less than or equal to 0.87 ng/mL after 1 year, based on the weighted average of PSA velocity (PSAV) in previous studies in similar populations. Secondary outcomes were disease progression, adverse histology on repeat biopsy or switch to active therapy. In addition, primary and secondary outcomes with imputed data were also determined as sensitivity analyses, using Mann–Whitney U or Chi-squared tests. Results: Overall, 92 (61.3%) of 150 patients showed a PSA level response. This was more evident in ISUP 1 patients and resulted in fewer follow-up MRIs and fewer control biopsies, as well as a fewer number of positive control biopsies with statistical significance in the imputed dataset. Obtaining a PSA response was numerically associated with less initiated therapy. Conclusions: a fermented soy supplement in patients under AS for low-risk and selected favorable intermediate-risk PCa could be useful in selecting patients who may remain under AS or who may need to switch to active therapy.

Comparison of Antioxidant Components and Activities of Korean Black Soybeans

Comparison of Antioxidant Components and Activities of Korean Black Soybeans

Dynamic Landscapes of Long Noncoding RNAs During Early Root Development and Differentiation in Glycine max and Glycine soja.

Soybean (Glycine max) is an important crop for its nutritional value. Its wild relative, Glycine soja, provides a valuable genetic resource for improving soybean productivity. Root development and differentiation are essential for soybean plants to take up water and nutrients, store energy and anchor themselves. Long noncoding RNAs (lncRNAs) have been reported to play critical roles in various biological processes. However, the spatiotemporal landscape of lncRNAs during early root development and differentiation in soybeans is scarcely characterized. Using RNA sequencing and transcriptome assembly, we identified 1578 lncRNAs in G. max and 1454 in G. soja, spanning various root portions and time points. Differential expression analysis revealed 82 and 69 lncRNAs exhibiting spatiotemporally differential expression patterns in G. max and G. soja, respectively, indicating their involvement in the early stage of root architecture formation. By elucidating multiple competitive endogenous RNA (ceRNA) networks involving lncRNAs, microRNAs and protein-coding RNAs, we unveiled intricate regulatory mechanisms of lncRNA in early root development and differentiation. Our efforts significantly expand the transcriptome annotations of soybeans, unravel the dynamic landscapes of lncRNAs during early root development and differentiation, and provide valuable resources into the field of soybean root research.

Have We Selected for Higher Mesophyll Conductance in Domesticating Soybean?

Soybean (Glycine max) is the single most important global source of vegetable protein. Yield improvements per unit land area are needed to avoid further expansion onto natural systems. Mesophyll conductance (gm) quantifies the ease with which CO2 can diffuse from the sub-stomatal cavity to Rubisco. Increasing gm is attractive since it increases photosynthesis without increasing water use. Most measurements of gm have been made during steady-state light saturated photosynthesis. In field crop canopies, light fluctuations are frequent and the speed with which gm can increase following shade to sun transitions affects crop carbon gain. Is there variability in gm within soybean germplasm? If so, indirect selection may have indirectly increased gm during domestication and subsequent breeding for sustainability and yield. A modern elite cultivar (LD11) was compared with four ancestor accessions of Glycine soja from the assumed area of domestication by concurrent measurements of gas exchange and carbon isotope discrimination (∆13C). gm was a significant limitation to soybean photosynthesis both at steady state and through light induction but was twice the value of the ancestors in LD11. This corresponded to a substantial increase in leaf photosynthetic CO2 uptake and water use efficiency.

The LTAR Croplands Common Experiment at Upper Mississippi River Basin-Ames.

Agricultural systems evolve from the interactions of climate, crops, soils, management practices (e.g., tillage, cover crops, nutrient management), and economic risks and rewards. Alternatives to the corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] (C-S) cropping systems that dominate in the US Midwest may provide more sustainable use of resources, reduce the documented environmental impacts of current C-S systems, and improve production efficiency and ecosystem services. Innovative management practices are needed to offer producers options to increase farm resilience to variable weather conditions and offset negative environmental impacts. In response to this need, the Upper Mississippi River Basin Long-Term Agroecosystem Research network site at Ames, IA, established a cropland experiment in 2016 to investigate an alternative crop management system that includes reduced tillage, cover crops, and right source, right rate, right time, and right place (4R) nitrogen (N) management. The experimental site is located on the Iowa State University Kelley Research Farm in Boone County, IA. Crop, soil, air, and tile drainage water measurements are made throughout the year using published methods for each agronomic and environmental metric. Our goal is to provide quantitative information to farmers, consultants, agribusiness partners, and state and federal agencies to help guide decisions on the effective use of alternative management practices. Future changes in experimental treatments will adopt a knowledge co-production approach whereby researchers and stakeholders will work collaboratively to identify problems, implement research protocols, and interpret results.

Quantifying the rainfall variability effects on crop growth and production in the intensified annual forage - winter wheat rotation systems in a semiarid region of China

Replacing summer fallow period (July to September, SF) with annual short-season forages in the traditional fallow-winter wheat (Triticum aestivum L.) system may maintain grain yield and improve productivity in the semi-arid environments. But the uneven and variability rainfall led to instable productivity of the annual forage–winter wheat cropping system. The aims of this study were to 1) quantifying rainfall variability effects on annual forage–winter wheat system crop growing process and productivity; 2) determine the optimal annual forage–winter wheat production system that will response better to future climate change. A four-year (2016–2020) field experiment was conducted to investigate the impact of replacing summer fallow period with annual forages including oat (FO, Avena sativa L.), soybean (SB, Glycine max L.), and vetch (FV, Vicia sativa L.) on plant height (H), leaf area index (LAI), and above-ground biomass (AByield) growth index dynamics under three different levels of rainfall manipulation i.e. 30 % of ambient rainfall exclusion (R-30 %), natural rainfall (CK), and 30 % of ambient rainfall increase (R+30 %). Additionally, we assessed the correlations between forage and winter wheat production with growing season precipitation across 12 rainfall scenarios. Average forage biomass values of oat, soybean, and vetch were 5.50, 4.29, and 2.82 t ha−1, respectively during summer fallow period. The average winter wheat grain yield values in SF, FO, SB, and FV were 3.78, 3.12, 4.02, and 3.18 t ha−1, respectively. Integrating oat into fallow period had negative effects on wheat growth and production, and the H, LAI, and AByield for FO were 63.7 %, 50.9 %, and 29.9 % lower than SF in dry year, but the wheat grain yield in SB were 18.2 % and 24.8 % greater than SF in normal and wet years. Across the four growing seasons, the forage and wheat yields were shown to be strongly related to precipitation, and increasing precipitation significantly enhanced the production. In 2016–2017 growing season, LAI of wheat in SF, FO, SB, and FV with R+30 % scenario was increased by 30.2 %, 21.7 %, 32.7 %, and 19.8 % and that with R-30 % scenario decreased by 23.2 %, 17.8 %, 24.7 %, 16.5 % compared CK, respectively. The traditional summer fallow practice had advantage for maintaining stability in wheat gain production, especially under dry years. In consideration of forage and wheat production to rainfall variability, integrating soybean into fallow season may be an efficient option to maintain wheat yield and produce high forage amount under future climate change on the Loess Plateau and similar semi-arid regions.