Little is known about the effect of field management on soil quality in mining subsidence landscapes. In this study, we selected subsided cropland from the Jiaozuo coal mining district, China, to determine the effects of irrigation and tillage on soil organic carbon (SOC) and nutrients. Irrigation and tillage differentially affected the dynamics of SOC, total nitrogen (N) and total phosphorus (P) in subsided cropland at 15–18 years after surface subsidence. Tillage along a longitudinal slope-direction induced greater depletions of SOC, N and P stocks in subsided cropland compared with tillage along a transverse slope-direction (TT). These parameters were also more depleted under rainfed than under irrigated conditions. The distribution of SOC, total N and total P was related to soil redistribution by soil erosion in subsided cropland. Integrated irrigation-TT management reduced the within-field variations in SOC, total N and total P, and irrigation reduced within-field variation in SOC. These results indicate the effects of tillage and irrigation on soil erosion and subsequently on SOC and nutrients in subsided cropland. Practicing tillage over great subsidence gradients is detrimental to soil conservation. Combining small subsidence gradients with irrigation may be an alternative to traditional engineering reclamation of subsided cropland.
Evolution of the transport properties of soil aggregates and their relationship with soil organic carbon following land use changes