Soil health responses of circular grass buffer strips in center‐pivot irrigated agriculture

Abstract

AbstractDecline in water table in the Ogallala Aquifer, along with soil degradation, has threatened the sustainability of agriculture in the US High Plains region. Circular grass buffers in center pivot irrigated cropping systems could support sustainable crop production by providing multiple ecosystem services. This study evaluated soil organic matter (SOM), nutrients, and other selected soil health indicators under circular buffer strip grasses (BSG), adjacent buffer strip corn (Zea mays L.) (BSC), and continuous conventional corn (CCC) in the 0–80 cm soil profile. Soil samples were collected from the center of corn and grass strips for 5 years (2017–2021) and analyzed for nitrate N (NO3−‐N), soil pH, electrical conductivity, cation exchange capacity, SOM, and soil nutrients. The NO3−‐N under CCC in 0–20 cm (18.4 mg kg−1) and 60–80 cm (4.97 mg kg−1) were 1.56 and 1.96 times higher than BSC. The NO3−‐N was significantly lower under BSG than other treatments in 0–20 cm, 20–40, and 40–60 cm depths. The SOM was similar among all treatments. Response of other nutrients varied among treatments and inter‐annually. Soil pH in 0–20 cm depth was 0.1 and 0.3 units lower in CCC (pH = 7.7) than in BSC and BSG. Soil electrical conductivity was 37.5% and 25% greater in CCC than BSG (0.24 and 0.24 dS m−1) in 0–20 and 20–40 cm depths, respectively. Grass buffer strips maintaining SOM despite no irrigation, less residual N under corn with grass buffer, and less rapid changes in soil pH suggest the potential of grass buffer to maintain soil health in semi‐arid cropping systems facing the transition to dryland.