Unsustainable agricultural practices deplete soil organic carbon (SOC), affecting ecosystem services, land productivity, soil health, and water quality. This study evaluated the long-term effects of row crop (RC), agroforestry buffers (AB), grass buffers (GB), and grassed waterways (GWW) on SOC. Agroforestry buffers (grass and tree) and grass buffer treatments were established in 1997 on a corn (Zea Mays L.)soybean (Glycine Max [L]. Merr.) rotation. Grid soil samples from 86 locations were collected in 10 transects to determine SOC at 0-10 and 10-20 cm depths. The general linear model and the generalized linear mixed model were conducted to evaluate treatment, landscape, soil depth, and series effects on SOC. Kriging interpolation was used to visualize the temporal and spatial change of SOC in the watersheds, comparing samples collected in 2000 and 1994 with samples collected in 2020. The mean SOC percentage (SOC%) in the top 10 cm depth for the RC, AB, GB, and GWW areas was 1.94, 2.19, 2.41, and 2.51%, respectively (ρ < .001). The soil depth was significant (ρ < .001) between samples from 0-10 cm and 10-20 cm. The mean SOC% among soil series showed no significant differences at the studied depths. The mean SOC% of 0-10 cm for RC, AB, and GWW were 1. 85, 1.88, and 2.30% in 2000 and 1.94, 2.19, and 2.51% in 2020. The foot-slope position had the highest (2.41%) and the summit position had the lowest SOC (2.02%) percentages. The SOC% in the RC treatment from 0-10 cm at the summit, backslope, and foot slope positions were ranked 1.83 < 2.22 < 2.31%, respectively. Perennial vegetation and undisturbed land management practices increased SOC compared with the RC areas.

Agricultural practices often contribute to the transport of solutes into groundwater; thus, low‐cost strategies that extract nutrients from groundwater are essential to address water pollution. This study evaluated the effects of agroforestry (tree + grass; AB [cottonwood {Populus deltoides Bortr. ex Marsh.}]) and grass buffers (GB; [tall fescue Schedonorus phoenix (Scop.) Holub, Red clover {Trifolium pretense L.}, and Lespedeza {Lespedeza Michx}]) on groundwater nitrogen (N) concentrations. The experiment consisted of two grazing watersheds, one with an AB and another with a GB treatment. Buffers were not grazed since 2001. Three wells representing summit, backslope, and foot‐slope positions were installed at each watershed. Water samples were collected biweekly from November 2019 to January 2022 and analyzed for total nitrogen (TN) and dissolved N (DN). Dissolved nitrogen (DN) and TN concentrations after the AB in the foot‐slope well were 99% (5.36–0.06 mg L−1) and 85% (9.04–1.37 mg L−1) lower than the mean concentration of the summit and backslope wells. Similarly, DN and TN concentrations after the GB in the foot‐slope well were 94% (1.95–0.11 mg L−1) and 62% (2.86–1.07 mg L−1), lower than the mean concentration of the summit and backslope wells. Dissolved N concentrations were lower during warm periods probably due to plant uptake and denitrification in the buffer zone. Results showed that buffers, especially with deep‐rooted trees in the proximity of the water table, decreased TN and DN concentrations in groundwater and can be used as a conservation practice to address water pollution.

Soil thermal properties play many major roles in a soil as they influence the soil temperature and define the soil microclimate, which regulates many soil health parameters as well as life cycles of soil biota. Although cover crops (CC) can affect soil thermal properties, they are one of the least studied areas. This study compared the effects of CC on soil thermal properties in a corn (Zea mays L.) cropping system at the Elsberry Plant Material Center–USDA in Missouri (USA). The study design consisted of (a) no‐till CC (NC), (b) conventional till no CC (CN), (c) no‐till no CC (NN), and (d) grass (G) treatments. The first CC establishment in the NC treatment was done in October 2019. Soil cores were collected in April 2021 from 0‐to‐40‐cm depth at 10‐cm increments (96 samples) and analyzed for volumetric heat capacity (Cv), soil thermal conductivity (λ), soil thermal diffusivity (α), soil organic carbon (SOC), bulk density (BD), and volumetric water content (θ). As per the results, NC did not significantly improve SOC, BD, or soil thermal properties, because the biomass accumulation by CC was not enough due to the lack of CC establishment duration. The G treatment showed significantly higher Cv and lower λ in several soil depths. The study outcomes suggested that long‐term maintenance of CC with cropping systems are needed in quantifying the effects of CC on soil thermal properties.