Abstract Farmers are showing a growing interest in soil health. Therefore, it is necessary to understand how and when indicators respond to changes in land management. Measurements of soil carbon (C) and nitrogen can take up to a decade to shift. However, it is unknown how other biotic markers of soil health (i.e., nematode communities) react. Here we use the long‐term agroecosystem research trial at the W. K. Kellogg Biological Station to determine which biotic indicators respond first to the implementation of sustainable agricultural management. High‐diversity perennial forage and native prairie had higher nematode abundances compared to monoculture crops with perennial forage also being compositionally distinct. Additionally, nematode abundance was higher in the aspirational corn ( Zea mays ) treatment than conventionally managed corn ( p < 0.05). Mineralizable carbon (minC) was marginally greater in high plant diversity treatments ( p < 0.1). Overall, nematode abundance, in combination with incremental changes in labile C, are indicators of rapid shifts in soil health.

Abstract Microplastics are contaminants of global concern that are primarily studied in marine and urban environments. Understanding of microplastics in drained agricultural watersheds is lacking. We aimed to evaluate microplastics in ditch and tile drainage water through periodic sampling. Water samples were filtered to capture particulates that were digested to remove organics, then stained and evaluated using fluorescence microscopy and image analysis. Further, we compared and contrasted microplastic abundance, the current reporting standard, with microplastic mass concentration, often unreported, to determine the most accurate assessment. Open‐ditch drainage had greater microplastic contamination than drainpipe outlets. Agricultural drainage contained 2–6 orders of magnitude less mass concentrations of microplastics than sampled urban surface waters and laundry graywater. However, when evaluated by abundance, the difference was not apparent. These findings improve our understanding of microplastics in agricultural watersheds and demonstrate the importance of evaluating microplastic contamination based on mass concentrations for accurate assessments.Core Ideas Mass concentration (ng/L) is a better predictor of microplastic contamination than abundance (counts/L). Agricultural drainage water had lower microplastic mass concentrations than surface water or laundry graywater. Open‐ditch drainage had greater microplastic contamination than drainpipe outlets. Mass of microplastic pieces from smallest to largest: drainage water < river water < lake water = laundry water.

Abstract Organic management is widely regarded as an effective strategy to prevent soil degradation in agroecosystems. In this study, we investigated the abundance of soil microarthropods in a multi‐cropping system by comparing organic and conventional management practices. A total of 189 soil samples were collected from 63 agricultural sites cultivating three crops: paddy rice (Oryza sativa L.), soybeans [Glycine max (L.) Merrill], and vegetables [Cucurbita moschata (Duch.) Poir., Solanum melongena L., etc.]. An averaged generalized linear mixed model revealed that both organic management and vegetable cropping were associated with significantly higher microarthropod abundance. We also detected a positive interaction between the soil carbon‐to‐nitrogen ratio and organic nitrogen content, indicating that organically enriched soils provide favorable conditions for microarthropods. Our findings demonstrate that agricultural management practices, cropping systems, and soil nutrient profiles collectively shape the abundance of soil microarthropods.

Abstract The lime equivalence, expressed in calcium carbonate equivalent (CCE), is an important quality parameter of biochar as a soil amendment. This work measured the CCE values and the relevant physicochemical parameters of seven defatted cottonseed meal‐, seven poultry litter‐, and five wood‐based biochar products. The CCE of the 19 biochar samples covered a wide range of values from 2.75 to 128.0 g CaCO3 kg−1. Furthermore, the lime equivalence showed a significant (p < 0.05) correlation with the pH parameter, but not (p > 0.05) with the organic content, ash content, electrical conductivity, and sum of soluble base cations. As biochar products with greater lime equivalence have the advantages to substantially reduce soil acidity and improve soil fertility, information derived from this work would shed light on biochar product optimization and appraisals for preferably rectifying strongly acidic soils via efficiently neutralizing soil acids, raising soil pH, and enhancing soil health and productivity.Core Ideas Lime equivalence values and relevant parameters of 19 agricultural and forest byproduct biochar samples were measured. The measured lime equivalence of biochar covered a wide range from 2.8 to 128.0 g CaCO3 per kg of mass. The lime equivalence of biochar samples shows meaningful (p < 0.05) correlation with pH parameter. Total soluble base cations show significant (p < 0.05) correlations with the electrical conductivity and ash content.

Abstract The Fertilizer Recommendation Support Tool (FRST) Project is a collaborative effort involving most land grant institutions, USDA branches, nonprofit organizations, and private industry. The FRST objectives are to develop a soil fertility community of practice, preserve soil test correlation and calibration data in a relational database, and develop a decision tool to provide consistent soil test interpretations. Released in April 2024, the interactive tool acts on an evolving database that contained 1455 P trials, 1316 K trials, and 143 S trials from 44 states and Puerto Rico by March 1, 2025. Decision tool outputs include an interactive county‐level map of available data and an estimated critical soil test value. The FRST relational database is a repository for soil‐test‐based P, K, and S data to support data‐driven management recommendations. Continued success of the FRST project and decision tool utility rely on collaboration and support from the soil‐test‐based nutrient management community.

Abstract Fertilizer overapplication remains a persistent challenge in several US watersheds. Farmer attitudes play a key role in nutrient management decisions, but few studies link farmer attitudes to phosphorus(P) fertilizer application rates. This study analyzes survey responses from 1650 Michigan corn farmers to assess P application behaviors and attitudes. The objective is to identify factors influencing P management and evaluate differences between P‐overapplying and non‐overapplying farmers. Overapplication is based on self‐reported P use and soil P levels, and differences are tested using chi‐square tests. Results show significant differences in attitudes, perceptions, and management practices between the two groups. Overapplying farmers express greater concern about nutrient runoff, suggesting they may be receptive to interventions. This study emphasizes the need to address P overapplication and improve information dissemination through agricultural consultants, soil testing laboratories, and extension services, as 55% of farmers reported not receiving recent information on P yield response.Core Ideas Farmer attitudes and perceptions are critical factors influencing management practice adoption. Self‐reported survey data for 1650 corn farmers in Michigan reveal phosphorus (P) fertilizer overapplication. Farmers that overapply P fertilizer have different attitudes than other farmers. Farmers overapplying P fertilizer indicate higher environmental concerns.

Abstract The safener fenclorim, effective in protecting rice (Oryza sativa L.) from the phytotoxicity of some herbicides, is regarded as a contaminant of emerging concern that may cause toxicological issues to ecosystems and humans who may consume the final harvested rice. This study investigated time‐dependent environmental releases of fenclorim from rice seeds treated with the safener and insecticide with five different treatments. The treatment with fenclorim alone caused the greatest fenclorim releases from the seed, and the release magnitude was similar to the treatment that had fenclorim and insecticide in mixture. The fenclorim release was the least when treated with safener and insecticide in sequence. Based on the previous literatures, all fenclorim release magnitudes observed in this study were at toxicologically safe levels for various living organisms in the soil, and fenclorim residues determined in the final rice harvest were also safe levels below the instrumentally detectable level.Core Ideas Seed treatment with safener alone causes the largest fenclorim release to environments. Seed treatment with safener and insecticide in sequence minimizes fenclorim releases. Fenclorim residues in the final rice harvest were below the detectable level. The fenclorim used will not cause residual issues in the ecosystem and harvested rice.

Abstract Phosphorus (P) is an essential nutrient applied as fertilizer in agricultural fields. However, excessive fertilization leads to P build up in soils, increasing its potential to cause environmental pollution. The objective of this study was to evaluate the average P drawdown rate of 56 sites with drawdown management presented in 14 publications. Soil test P (STP) results were converted to Mehlich‐3 equivalent and resampling analysis was used to compare the annual drawdown rate in fields grouped by four initial STP classes. The STP was reduced by 4.3%–8.2% per year, depending on the initial STP class. It took from 8.4 to 15.9 years to reduce the STP by half. The resulting equations from this meta‐analysis can be used by landowners to estimate the time needed for STP drawdown by cropping without additional P to achieve the desired STP concentration.Core Ideas Cropping without phosphorus (P) fertilization is one of the few options to reduce soil test P (STP). A meta‐analysis of the annual P drawdown rate was performed using 56 sites presented in 14 publications. Fields were grouped into four initial STP classes based on Mehlich‐3 STP equivalent. The STP was reduced from 4.3% to 8.2% per year in fields with high and low initial STP. The time needed to reduce the STP by half varied from 8.4 to 15.9 years depending on the initial STP.

Abstract Nitrous oxide (N2O) is a significant greenhouse gas and the most important currently emitted ozone depleting substance, primarily via agricultural fertilization. Current N2O emission estimation methods at the national scale are predominantly via emission factors. Models estimating national‐scale emissions are focused on growing season emissions. However, a substantial fraction of N2O can be emitted during non‐growing season periods. Using newly published off‐season N2O emission ratio maps and high‐resolution nitrogen application data, this study explores the potential magnitude of underestimated N2O emissions if using only the default growing‐season focused methodology. Although there is large variation at county scales (12%–35%), non‐growing season national emissions are estimated at 31% of the total, a potential 12,000 Gg CO2e year−1. Further work should better refine emission estimates spatially as well as fully integrate estimates across growing and non‐growing seasons.