Soil mixing with organic matter amendment improves Albic soil physicochemical properties and crop yield in Heilongjiang province, China.

Crop productivity in Albic soil is poor, owing to poor soil physicochemical properties. Mixing of Aw layers, representing Albic soil, with B layers, could improve the physicochemical properties of Albic soil, which is characterized by poor humus on the topsoil and high penetration resistance. The objective of the present study conducted in 2015-2016 in an Albic soil region in Heilongjiang province, China, was to explore the effects of different soil mixing strategies on the physicochemical properties of Albic soil and crop yield. There were four soil mixing treatments: conventional subsoiler (CS), three-stage subsoil mixing plough (TSMP), four-stage subsoil mixing plough (FSMP), and three-stage subsoil interval mixing plough (TSIMP). Our results demonstrated that the Aw layer bulk density of Albic soil under TSMP, FSMP, and TSIMP decreased significantly compared to that under CS. In addition, the total porosity of the soil under these treatments increased significantly in 2 years. Compared to the water holding capacity under the CS treatment, other treatments increased significantly in the Aw layer. Furthermore, soil penetration resistance of the Aw layer decreased following Aw and B layer mixing. All three soil mixing treatments also increased soil aggregate stability and cation exchange capacity but reduced soil organic carbon content in the Aw layer. Soil mixing increased soybean and maize seed yield. Overall, Aw and B layer mixing improved Albic soil structure and physiochemical properties and increased crop yield; thus, this mixing is a feasible approach for Albic soil improvement, with optimal improvements observed under the FMSP strategy, which also added organic substances to the Aw layer.