Effects of corn stover mulch quantity on mid-infrared spectroscopy of soil organic carbon in a no-tillage agricultural ecosystem

Abstract

We examined carbon chemical composition and stability along soil depth (topsoil 0-5 cm, mid-soil 20-40 cm, and deep soil 60-100 cm) in a no-tillage (NT) agricultural system with various amount of corn stover as mulch for 8 years, including 0 (NT0), 33% (NT33), 67% (NT67) and 100% (NT100), in Northeast China, using mid-infrared spectroscopy. The results showed that, relative to NT0, the treatments of NT33 and NT100 increased polysaccharide content of the top layer and mid-layer soils, the former decreased topsoil carbon component diversity, while the latter maintained soil carbon stability of three soil layers. NT67 increased carbon stability at the deep layer soil. Our results demonstrated that if corn stover resources were sufficient, NT with 100% corn stover mulch could both be beneficial to carbon availability at 0-40 cm soil layer and stability of the whole soil profile. The nonlinear relationship between the amount of corn stover mulch and the mid-infrared spectral characteristics of the soil called for further research on the microbial-control mechanism over soil carbon cycling under different amounts of corn stover mulch.