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Cover cropping has the potential to generate private economic benefits to farm operations as well as larger-scale environmental benefits to the broader community. However, cover crop adoption remains limited in the United States (US) (i.e., 4.7 % in 2022 (USDA-NASS, 2024)), primarily due to uncertainty in economic outcomes, with several studies showing potentially negative net returns from cover crop use in the short-term (1–3 years). This study investigates the medium-term (5–7 years) economic impact of cover crop adoption using plot-level data from field experiments in the state of Maryland. The empirical analysis employs ordinary least squares (OLS) statistical models and partial budgeting techniques to achieve the study objective. Our results show that cover crops do not have a statistically significant effect on crop yield, fertilizer costs, or pesticide costs, but we find that cover crop use statistically increases field operation and seed expenses. As a result, the private net return from cover crop adoption in the medium term is generally negative based on the Maryland field trial data used in the analysis. Specifically, the average net return per acre with cover crops is approximately $60-$90 lower for corn and around $60 lower for soybeans compared to fields without cover crops. This empirical finding suggests that public support through incentive payments may help further incentivize cover crop adoption in the US, which can then provide environmental and ecosystem services that are of benefit to the general public.

Abstract Soils contribute 15%–75% of total atmospheric nitrogen oxide (NOx) emissions in agricultural regions during the growing season. However, the impacts of cropland fertilizer management on spatially heterogeneous, temporally episodic NOx emission patterns are highly uncertain. We examine the effects of liquid slurry dairy manure application practices on soil NOx emissions in rainfed, corn‐soybean rotations during spring 2016 and 2017. Daily soil NOx emissions and weekly soil inorganic N measurements were performed in a randomized split–split plot design for 1–4 weeks following manure applications. NOx emissions and soil N with shallow‐disk injection and chisel‐disk manure incorporation methods were compared with unincorporated broadcast practices. Injected manure and chisel‐disk incorporation exhibited two–four times larger mean NOx emissions than those with unincorporated broadcast manure. Larger soil NOx emissions with manure incorporation practices were driven by the predominance of nitrification in these treatments with evidence of soil nitrate production. Soil NOx emission differences between treatments were detectable across order of magnitude changes in daily NOx emissions during two growing seasons. Larger soil NOx emissions associated with manure incorporation practices compared with unincorporated broadcast practices occur alongside larger N2O and smaller NH3 emissions, highlighting important air quality and climate impact tradeoffs for cropland manure fertilizer management choices.

Maximizing living cover and minimizing soil disturbance with no-till are key strategies in regenerative row-crop production. Although living cover and no-till can increase beneficial soil carbon and water stable aggregates (WSA), annual crops in rotation with perennials often rely on herbicides to control weeds and terminate perennials. Integrated weed management (IWM) reduces reliance on herbicides by employing multiple weed control strategies including tillage and/or cultivation. However, many no-till growers are reluctant to implement some soil disturbance due to concerns about negative impacts on soil health. For that reason, we hypothesized that compared to continuous no-till and standard herbicides (NT-SH), a strategic inversion tillage in IWM (ST-IWM) would result in lower soil carbon and WSA in the year following the tillage event. We also hypothesized that soil carbon and WSA would not differ between the two systems when sampled after cover cropping and 2 years of perennials. We tested these hypotheses within a 6-year, diverse, dairy crop rotation initiated in 2010 in central Pennsylvania in a channery silt loam soil. The systems were compared in split-plots in a full crop entry experiment, where the six phases of the crop rotation were planted every year in a randomized complete block design, replicated four times. We compared the soil health indicators in spring 2010 prior to the start of the experiment and in 2013 and 2019 following inversion tillage (ST-IWM) or herbicide termination (NT-SH) of the perennial forage in the first year of the rotation. We also compared these indicators in the sixth year of the rotation after 3 years of annual and cover crops and 2 years of perennial forage. We sampled at two depths: 0–5 and 5–15 cm for total carbon and bulk density, 0–5 cm for labile carbon and 0–15 cm for WSA. Results indicate that despite initial smaller soil health values in the ST-IWM system following inversion tillage, all properties except labile carbon were similar to the NT-SH system in the sixth year of the rotation.

Sustainable nutrient management requires redistribution of livestock manure from nutrient-excess areas to nutrient-deficit areas. Field experiments were conducted to assess agronomic (i.e., corn yield) and environmental (i.e., ammonia volatilization and surface nutrient loss) effects of different poultry litter application methods (surface vs. subsurface) and timings (fall vs. spring) in a potential manure-importing region in the Chesapeake Bay Watershed in the United States. All four litter treatments (205 kg nitrogen ha) produced grain yields (10.9–12.8 Mg ha) nearly equivalent to or higher than the 11.5 Mg ha yield expected from the same mineral nitrogen rate. Compared with surface application, subsurface application significantly reduced ammonia emission ( < 0.0001), runoff volume (fall: = 0.02; spring: = 0.004), and loads of nitrate nitrogen ( < 0.0001; = 0.003) and dissolved phosphorus ( < 0.0001; = 0.004) soon after application. Integrating subsurface manure application technologies into the manure redistribution programs would help ensure that the surplus nutrients being relocated provide a maximum agronomic impact and minimum environmental impact to the importing region.

Nitrous oxide is the largest source of greenhouse gas emissions from crop production. There is significant interest in targeting marginal lands for growing biomass crops, however little information is available on how this will affect N _2 O emissions from these crops. Furthermore, to characterize N _2 O emission at the farm level to quantify mitigation using measurements is time intensive, costly, and impractical. We selected a highly diverse watershed varying in soil texture and topography to compare two approaches for modeling soil N _2 O emissions using machine learning, intensive measurements of soil environment and climate variables, with the other only using remotely sensed variables. We confirmed that soil nitrogen was the most important variable followed by soil environment as influence by soil characteristic, topography, and climate. We also found that the machine learning model built on remotely sensed variables performed as well as when direct site level measurements were available. This finding supports the potential of using remotely sensed data to build machine learning models to characterize soil N _2 O emissions without the need for intensive soil measurements for entity level assessments.