Search Results (98)

Sudden death syndrome (SDS) and soybean cyst nematode (SCN) are major yield-limiting diseases in North American soybean production, with limited effective management options. Long-term soybean monoculture has been reported to suppress SDS and SCN, but the mechanisms, onset, and persistence of such suppression remain poorly understood. To study these mechanisms, a six-year field study (2018–2023) was conducted at two Ontario sites with contrasting disease histories: Chatham (conducive) and Essex (suppressive). We evaluated suppression development and resilience across soybean monoculture (SSSSSS) and corn–soybean rotations (SCSCSC/CSCSCS), using eight cultivars differing in SDS and SCN resistance across two maturity groups. In Chatham, disease index (DX) progressively declined under monoculture; the most susceptible cultivar, HS11RY07, declined from a mean DX of 89 to 43 by year six, with corresponding yield increases, and rotational yield advantages diminished. In Essex, introducing corn rotation increased SDS symptoms during soybean phases; monoculture yields became comparable to rotation in later years. Importantly, suppression developed without corresponding reductions in Fusarium virguliforme and SCN populations, which remained variable across years, suggesting that monoculture may disrupt pathogen effectiveness rather than eliminating it. This decoupling of pathogen abundance and disease severity is consistent with soil-mediated biological suppression; the microbial drivers are addressed in subsequent work. Full article

Evapotranspiration (ET) is a fundamental process within the water cycle and the agricultural water balance, optimizing resource allocation, maintaining soil health, and enhancing ecosystem resilience to climate change. Because ET represents a primary consumptive use of irrigation on agricultural lands, enhancing water-use efficiency and sustainable water management requires accurate estimation of evapotranspiration to support long-term sustainability and productivity. This study offers an effective means to visualize spatial and temporal patterns of reference evapotranspiration (ETo) across various vegetation management practices. This study examined the impacts of agroforestry buffers (ABs), grass buffers (GBs), biofuel crops in an agroforestry watershed (BCa), and biofuel crops in a grass buffer watershed (BCg) on ETo, compared to a corn (Zea mays L.)–soybean (Glycine max L.) rotation (RC) for claypan soil in Northern Missouri, USA. The experimental watersheds were located at the Greenley Memorial Research Center, Missouri, USA. Campbell Scientific sensors and Photosynthetically Active Radiation (PAR) smart sensors were installed to measure net radiation, anemometers, humidity, and air temperature. All instruments were mounted on masts at a height of 2 m above ground level in crop, tree, grass, and biofuel areas. Measured meteorological data were recorded hourly from April to October during 2017 and 2018. Daily ETo predictions were calculated using the Penman–Monteith model. These ETo predictions were displayed across the landscape using Python-based GIS for selected dates (each Saturday) for the watersheds. The methodology was implemented using the software programs of Python 2.7.10 and ArcGIS 10.3.1. The results indicated that ETo increased by 11%, 17%, 18%, and 25% in 2017, and by 7%, 9%, 14%, and 20% in 2018 for AB, BCa, BCg, and GB, respectively, compared to RC management. This process may improve soil water recharge in perennial management systems. Accurate estimation of ET in agricultural regions is critical for understanding water balance, hydrological and ecosystem processes, and climate variability. Given that agriculture constitutes the majority of global water consumption, precise ET estimation is particularly significant for sustainable water management, especially in regions experiencing water scarcity. These outcomes may support effective planning and management of agricultural water resources by enabling optimized irrigation and agricultural production. Full article

Soil quality (SQ) refers to the soil’s capacity, as influenced by management practices, to sustain productivity, maintain environmental quality, and provide essential ecosystem services. The impacts (2012–2016) of gypsum application, cover cropping, and crop rotation on SQ were evaluated under rainfed no-till (NT) systems at sites in Shorter, Alabama; Farmland, Indiana; and Hoytville and Piketon, OH, USA. Experimental treatments were arranged in a randomized complete block design in a factorial combination of gypsum (0, 1.1, and 2.2 Mg ha⁻¹), cover crop [cereal rye (Secale cereale) or no cover], and crop rotations as follows: soybean (Glycine max; SS), corn (Zea mays)–soybean (CS), and soybean–corn (SC). Composite soil samples were collected at 0–15 and 15–30 cm depths and analyzed for biological, chemical, and physical properties to compute a comprehensive SQ index (SQI_Comp). Principal component analysis identified a minimum dataset (MDS), including microbial biomass, organic carbon, and mean weight diameter, used to compute SQI_MDS. Applying gypsum at 2.2 Mg ha⁻¹ increased SQI_Comp by 3–7% and SQI_MDS by 7–17% at most sites compared with the control. The CS rotation produced the highest SQ, exceeding SS by 5–10%. Cover crops had minimal overall effects on SQ, except in Indiana. When averaged across all sites, SQ differences between depths were 19% for SQI_Comp and 33% for SQI_MDS. Significant linear relationships between SQI_MDS and SQI_Comp indicate that SQI_MDS accounted for most of the variability (R² = 0.77–0.94) in SQI_Comp. Overall, gypsum application at 2.2 Mg ha⁻¹ and the CS rotation improved surface SQ under NT systems, and SQI_MDS is better suited for relative comparisons than for absolute quantification. Full article

Straw returning is an effective means of improving soil structure and increasing soil organic matter content. However, few studies have been conducted on the effects of corn straw returning on the soil microorganism community in soybean crops. In this paper, taking conventional combined tillage (CT) as a control, the effects of no-tillage with straw mulching (NTS), no-tillage with stubble retention (NT), and deep plowing with straw incorporation (DT) on soil bacterial community under a corn–soybean rotation system were studied. The results showed that the contents of soil total nitrogen, total phosphorus, available phosphorus, the activities of soil urease and acid phosphatase, and soil bacterial richness and diversity in the NTS treatment were significantly higher than those in other treatments. Moreover, the NTS treatment increased the abundance of Acidobacteriota and MND1 (unclassified bacterial genus) in the soil. The number of unique OTUs in the NTS treatment was the greatest (26.67%), with that of the CT treatment being the smallest (7.22%). Redundancy analysis (RDA) revealed that soil total nitrogen, total phosphorus, and available phosphorus are the key driving changes in bacterial community. Consequently, NTS treatment was the optimal approach for both soil fertility improvement and bacterial community optimization. This approach combines straw mulching and no-tillage, which not only exerts the nutrient supply effect of straw but also reduces the impact of soil disturbance on microbial habitats. Full article

This study utilized a modeling approach to explore the long-term effects of integrating hybrid rye into organic crop production on crop yields and water use, and rye’s theoretical impact on feed and bedding self-sufficiency in organic pig production. Crop yield and water use were simulated using DSSAT models for three exploratory scenarios (R1: corn–soybean–silage followed by 3 years of alfalfa; R2: rye replaced the first year of alfalfa; and R3: rye replaced the third year of alfalfa). Potential feed and bedding requirements were estimated based on a recently completed pig feeding trial. The models predicted higher rye yields and water use in R3 than in R2 (p < 0.01), suggesting a theoretical yield benefit when rye follows alfalfa. Based on these simulations, R3 could potentially provide feed and bedding for a 38 pigs·ha⁻¹·rotation cycle⁻¹, compared to a 10 pigs·ha⁻¹·rotation cycle⁻¹ in R2. While these findings represent theoretical scenarios rather than validated field performance, they demonstrate the potential of crop simulations for evaluations of long-term effects of organic crop rotations on yield and water use. The results suggest that integrating hybrid rye after legumes warrants further field-scale validation as a strategy to enhance resource self-sufficiency in organic pig production. Full article

Strengthening cropping patterns and crop planting structure policies is significant for ensuring sustainable agriculture, with broader implications for food security and cultivated land quality conservation. In this context, enhancing the crop rotation project in China’s Black Soil region requires exploring the coupling relationship between the rotation ratio and crop planting structure. Selecting China’s Black Soil region as a case study, this paper presents an equation-based model to determine regional rotation probabilities for the years 2020 to 2021. The Tupu method of geo-information analysis is utilized to explore the characteristics of crop planting structures and rotations. Furthermore, the study explored the relationship between the rotation ratio and crop planting structure, with rotation probability serving as a mediator. The results revealed that corn had a significant impact on the crop planting structure due to its prevalence in continuous cropping. The area dedicated to corn and soybean rotation accounted for only 12.09%. Additionally, correlation analysis showed that a more balanced cropping ratio results in a higher rotation ratio. Therefore, this research suggests that increasing the subsidy standard for crops in relatively low areas and allocating rotation indicators from south to north may help improve the regional rotation ratio in the Black Soil region. These insights should guide policy formulation and implementation to promote sustainable agricultural practices and optimize the rotation policy in China’s Black Soil region. Full article

Most tropical soils, as in the case of Brazil, are highly weathered, with low fertility, high acidity, and toxic aluminum, which limits crop management. Promoting root development is essential to overcome these constraints, and agricultural gypsum has shown positive effects in no-tillage systems. This study evaluated the residual effects of five gypsum rates in an integrated crop–livestock system, with or without inoculation of rotation grasses with Azospirillum brasilense, on crop productivity and soil fertility over 40 months. The experiment was conducted in a randomized block design with four replications in a 5 × 2 factorial scheme. Inoculated grasses increased yields of soybean, sorghum intercropped with Paiaguás grass, and black oat, whereas non-inoculated areas had the highest corn yield, likely due to hybrid metabolism. Gypsum had limited effects on crop yields, with lower doses performing slightly better. Inoculation improved soil fertility, increasing base sum, cation exchange capacity, and base saturation up to 0.60 m depth at 18 and 40 months. After 40 months, gypsum enhanced soil conditioning and increased calcium, sun of bases, and base saturation. Overall, inoculation with Azospirillum brasilense in rotation grasses under long-term no-tillage systems enhanced crop productivity and contributed to improved soil fertility. Full article

Nitrous oxide (N₂O), a potent greenhouse gas (GHG) and major contributor to climate change, is primarily released through agricultural activities. To better understand and quantify how land management practices, local climate conditions, and soil physicochemical properties affect these agricultural N₂O emissions, we conducted a review of the peer-reviewed literature on N₂O emission from corn [Zea mays L.] and soybean [Glycine max (L.) Merr.] fields. We evaluated the seasonal, cumulative effects of three nitrogen fertilizer rates—no fertilizer (0), low (<188 kg N ha⁻¹), and high (188–400 kg N ha⁻¹)—tillage practices, local climate (precipitation and temperature), soil texture, and soil pH on soil N₂O emissions. This meta-analysis included 77 articles for corn and 22 articles for soybean fields. Average N₂O emissions during the corn rotation were 2.34 and 2.45 kg N₂O-N ha⁻¹ season⁻¹ under low and high N fertilizer rates, respectively, and were both substantially (p < 0.0001) greater than those of non-fertilized corn fields (0.91 kg N₂O-N ha⁻¹ season⁻¹). Non-fertilized soybean fields showed seasonal N₂O emissions of 0.74 kg N₂O-N ha⁻¹, while low fertilizer application triggered a sharp increase (1.87 kg N₂O-N ha⁻¹) in N₂O emissions by roughly 2.5 times (p < 0.028). Increased temperature did not significantly (p > 0.05) affect the emission of N₂O from fertilized or non-fertilized corn fields. Regardless of fertilization and tillage practices, our analysis, including Principal Component Analysis, revealed that in corn fields, precipitation and soil pH are the dominant factors influencing soil N₂O emissions. This study uniquely quantifies the influence of climate–soil factors, such as precipitation and soil pH, alongside agronomic practices, on N₂O emissions, offering new insights beyond previous reviews focused primarily on fertilizer rates or tillage effects. Full article

Phosphorus inputs play a critical role in modulating microbial dynamics in crop rhizosphere soils, yet their specific effects remain underexplored. This study investigated the impacts of P addition on soil respiration rates, enzyme activities, and microbial communities in maize and soybean rhizosphere soils under a 20-year corn-soybean rotation system. Results demonstrated that P inputs significantly elevated rhizosphere soil respiration rates. In maize, LP treatment yielded the highest initial rate (3.2 times CK on day 0) and maximum rate (1.45 times CK), peaking early (days 0–4). In soybean, HP treatment produced the peak rate, occurring on day 4. Glucosidase activity increased under P treatments, with HP in maize showing values up to 1.5–2 times CK before day 8, and HP in soybean peaking at 1.2 times CK on day 8. Acid and neutral phosphatase activities generally declined initially, reflecting feedback inhibition, while alkaline phosphatase rose early. Microbial community structure shifted markedly. Key taxa like Reyranella and Luteimonas increased with P concentration, while Gp1 decreased. Correlation analysis indicated strong associations; e.g., Proteobacteria positively correlated with acid phosphatase and negatively with neutral phosphatase. These findings underscore the crop-specific responses of rhizosphere microbiomes to P inputs, informing targeted fertilization strategies for enhanced nutrient efficiency and sustainable agriculture. Full article

Soybeans (Glycine max L.), a globally significant crop, play a critical role in economic, nutritional, and ecological systems, particularly in rotational farming due to their nitrogen-fixing capacity. This study investigated the residual effects of vermicompost (VC) and vermicompost tea (VCT) applied during a preceding corn cycle on subsequent soybean growth and productivity in an organic corn–soybean rotation. Soybeans were grown in raised beds previously treated with different VCT concentrations and combinations of VC+VCT, without additional fertilization during the soybean phase. Physiological traits, including leaf chlorophyll content (SPAD values) and stomatal conductance, were measured alongside biomass, yield, and plant leaves nutrient concentrations. VC+VCT treatments significantly increased biomass and yield, with VC1+VCT20 achieving the highest biomass (3.02 tons/ha) and yield (1.68 tons/ha). Leaf nutrient analysis revealed increased uptake of both macro- and micronutrients in amended treatments, while SPAD and stomatal conductance values remained consistently higher than in the control. Soil analyses confirmed improved nutrient retention and cation exchange capacity in amended plots, demonstrating the legacy benefits of organic inputs. Therefore, residual VCT and VC+VCT applications improved soybean productivity, nutrient acquisition, and physiological performance in rotational systems. By reducing reliance on synthetic fertilizers and enhancing soil fertility, this strategy supports climate-smart agriculture principles and contributes to SDG 2 (Zero Hunger), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action). Full article

To address the challenges of low density, loose structure, high utilization costs, and inadequate molding effects of corn straw char under ambient temperature and pressure conditions, this study investigated the utilization of waste soybean powder (WSP) as a binder to produce biochar pellets via ultrasonic-assisted processing. A single-factor experiment was initially conducted to assess the effects of key variables. Subsequently, a Central Composite Rotatable Design (CCRD) was employed to evaluate the individual and interactive effects of these variables, in which pellet density and durability served as response indicators. Regression models for both responses were developed and validated using analysis of variance (ANOVA). The results indicated that, at a 0.05 significance level, the mixing ratio of corn straw char to WSP and molding pressure had highly significant effects on pellet density, while pelleting time had a significant effect and ultrasonic power had no significant influence. All four factors significantly affected pellet durability, and their interactions were further analyzed. The optimal conditions were a mixing ratio of 45%, pelleting time of 33 s, an ultrasonic power of 150 W, and a molding pressure of 5 MPa, yielding pellets with a density of 1140.41 kg/m³ and a durability of 98.54%. These results demonstrate that WSP is an effective binder for the ultrasonic-assisted fabrication of biochar pellets. Full article

Allelopathy plays a major role in agricultural production, influencing plant protection, crop yield, and crop rotation systems. This study investigated the effects of root exudates on 3105c alfalfa (Medicago sativa) seeds and seedlings to identify crops with strong and weak allelopathic potential. The results revealed that corn (Zea mays L.) (T1) exhibited the strongest allelopathic effects, whereas soybean (Glycine max (Linn.) Merr.) (T10) exhibited the weakest effects. T1 promoted seed germination by increasing radicle length and the simple vitality index. Both T1 and T10 promoted 3105c seedling growth and enhanced antioxidant capacity, albeit through different mechanisms. T1 primarily increased antioxidant capacity by elevating ascorbate and dehydroascorbate levels while reducing malondialdehyde content. In contrast, T10 enhanced antioxidant capacity by increasing soluble sugar and protein levels via hydroxyl free radical inhibition. These findings demonstrate that the allelopathic properties of corn effectively promote alfalfa growth by enhancing seed germination and improving physiological stress resistance. Full article

Salt-affected soil areas are increasing in the Northern Great Plains (NGP), with patches occurring in some of the most productive croplands. High electrical conductivity (EC) and sodium and/or sulfate concentrations of saline–sodic areas impede the growth and yield of ‘normal’ [corn (Zea mays)/soybean (Glycine max)] rotational crops, and more appropriate management systems are needed. Brassica spp. and amendment applications, such as biochar, may provide management alternatives for these areas. In two greenhouse studies, (1) 10 canola (Brassica napus) genotypes were evaluated for emergence in non-saline (EC_1:1 = 0.62 dS m⁻¹), moderately saline–sodic (EC = 5.17 dS m⁻¹), and highly saline–sodic (EC_1:1 = 8.47 dS m⁻¹) soils and (2) 10 canola genotypes and 3 other brassicas (Brassica juncea/B. oleracea) were evaluated for emergence and biomass in non-saline or moderately saline–sodic soils with or without two 5% biochar (hardwood or softwood) amendments. Canola emergence at 28 days after planting (DAP) in moderately and highly saline–sodic soils was less than 12% for most genotypes, although one had 37% emergence. The hardwood biochar improved Brassica spp. emergence (42%) from the moderately saline–sodic soil compared to non-amended soil (29%), although shoot biomass was similar among treatments at 60 DAP. These findings suggest that specific salt-tolerant Brassica spp. may be an alternative crop for NGP saline–sodic soil areas. Florida broadleaf mustard, typically used for forage, had the greatest emergence (52%) in the saline–sodic soil and may be a suitable cover crop for these areas. In addition, hardwood biochar applications may aid in plant establishment. Full article

Cropping sequence can have a major impact on diseases, pests, nutrient cycling, crop yield, and overall financial return at the farm level for crops that are grown on an annual basis. In some cases, implementing an effective rotation sequence can allow growers to avoid using nematicides to suppress plant-parasitic nematodes. Two cropping system trials were established with ten rotations each in 1997 and have been maintained through 2022. From 2013 through 2019, rotation sequences were both favorable and unfavorable for peanut (Arachis hypogaea L.) plant health. Peanut (2020), cotton (Gossypium hirsutum L.) (2021), peanut (2022), and corn (Zea mays L.) (2023) were planted in all plots to determine the residual effects of the previous cropping sequence. In 2020, 2021, and 2022, fluopyram at 0.25 kg ai/ha was applied in the seed furrow at planting in the same area of each plot to determine if the response of nematode populations and crop yield to this nematicide differed based on previous crop sequence. Differences in nematode populations in soil and yield of peanut (2020 and 2022) and cotton (2021) were observed when comparing crop rotation sequences regardless of fluopyram treatment. Increasing the number of years peanut was in the rotation or including soybean [Glycine max (L.) Merr.] rather than corn or cotton often resulted in higher populations of nematodes and a lower peanut yield. While fluopyram occasionally reduced nematode populations in soil and root injury from nematode feeding, the yield of peanut did not differ when comparing non-treated and fluopyram-treated peanut. When pooled over crop rotation sequence, peanut yield at Lewiston–Woodville was 5970 kg/ha vs. 6140 kg/ha for these respective treatments. At this location in 2021 and at Rocky Mount in 2019 and 2020, peanut yield for this comparison was 4710 vs. 4550, 5790 kg/ha vs. 6010 kg/ha, and 6060 kg/ha vs. 6120 kg/ha, respectively. These data indicate that previous crop sequences can influence crop yield more than the continuous use of fluopyram. Therefore, fluopyram is not recommended for application in the seed furrow at planting to suppress nematodes in cotton or peanut in North Carolina. Full article

Soybean root rot, a soil-borne fungal disease, is caused by multiple pathogens that seriously affect soybean production. During spring 2021, 92 pathogenic fungal strains were isolated from soybean plants with root rot in Hailun City, Heilongjiang Province, China. Through morphological and molecular identification, these strains were identified as Fusarium oxysporum (39.1%), F. asiaticum (30.4%), F. graminearum (13.0%), Pythium macrosporum (8.7%), and Rhizoctonia solani (8.7%). Among them, F. oxysporum was the dominant species, and F. asiaticum, not previously reported as a soybean root rot pathogen in Northeast China. Approximately 50% of the F. asiaticum isolates were moderately pathogenic. In addition, F. asiaticum had a wide host range, infecting black soybean, French bean, white hyacinth bean, mung bean, and adzuki bean but not corn, peanut, rice, and oat roots. Regarding field management, fludioxonil and pyraclostrobin had the best control effects of 73.8% and 69.4%, with EC₅₀ values of 0.0029–0.0071 μg·mL⁻¹ and 0.0045–0.0076 μg·mL⁻¹, respectively. The study reported that F. asiaticum is a pathogen causing soybean root rot in northeast China. The application of chemical fungicides and non-host crop rotation can effectively control the disease caused by F. asiaticum. Full article