Furrow-irrigated corn residue management and tillage strategies for improved soil health

Conversion from conventional tillage to no-till in surface irrigated agroecosystems is low, mostly due to difficulties crop residue creates for water surface flow if no-till is implemented. A three-year continuous corn (Zea mays L.) study was conducted to evaluate the effects of residue management (retained yet mechanically moved out of the irrigation furrow, grazed, or baled/removed) and tillage (conventional tillage versus no-till) on soil health as verified using the Soil Management Assessment Framework. After three years of implementation, corn yields were 15% greater under no-till as compared to conventional tillage (13.1 versus 11.4 t ha⁻¹), and followed the order baled (13.6 t ha⁻¹) > grazed (12.5 t ha⁻¹) > retained (10.6 t ha⁻¹). In terms of corn residue management, soil health followed stover grazed = stover retained > stover baled/removed, a function of lower salts and greater plant-available K, beta-glucosidase activity, potentially mineralizable N, and microbial biomass C present – a result of greater water-stable aggregates and grazing’s influence on K and organic inputs. Reduced soil physical health was associated with a short-term increase in bulk density under no-till, while improved soil chemical health was associated with reductions in soil salts under no-till. Greater soil biological health was noted in the soil surface with no-till, due to greater beta-glucosidase activity, microbial biomass C, and a slight increase in soil organic C; the opposite was found with conventional tillage and soil depth. However, when combining the above observations, greater overall soil health was observed in the upper soil as associated with no-till as compared to conventional tillage; subsoil had greater overall soil health associated with conventional tillage. Understanding the importance of crop residue utilization in conjunction with no-till practices in surface irrigated agroecosystems can influence the adoption of sustainable management practices and should directly contribute to long-term soil health improvements and agroecosystem sustainability.