Cover Crops and Returning Residue Impact on Soil Organic Carbon, Bulk Density, Penetration Resistance, Water Retention, Infiltration, and Soybean Yield

Residue management with cover crops (CC) can conserve soil moisture and thus has a potential to increase crop yield, but its effectiveness varies significantly by region and cropping system management. A study was conducted at Brookings, SD, on finesilty, mixed, superactive, frigid, Calcic/Pachic Hapludolls soils to understand the impact of CC and crop residue on soil properties and soil-water dynamics for soybean (Glycine max L.) crop grown after corn (Zea mays L.). The site had two crop residue treatments (residue returned [RR] and residue not returned [RNR]) under a no-till corn–soybean rotation. Each residue returned treatment was later subdivided to include CC and no CC (NCC) treatments. Results from this 3 yr (2014, 2015, and 2016) study showed that RR (1.30 Mg m–3) had 7% lower bulk density (BD) compared to the RNR (1.40 Mg m–3). Soil organic carbon (SOC) was 22% higher under RR (26.2 g kg–1) compared to RNR (21.5 g kg–1). Soil water infiltration was 66% higher under RR (108 mm h–1) compared to RNR (64.8 mm h–1). Similarly, soil water infiltration in CC treatment (111 mm h–1) was 80% higher compared to NCC (61.7 mm h–1). The RR with CC treatment increased soil volumetric water content and soil water storage. Overall, the CC increased soybean yield by 14% compared to NCC. Data from this study suggest that the use of CC with RR are beneficial for improving soil properties, conserving soil moisture and enhancing crop yield