Organic Fertilizer and Amendment Improve Physical Properties of Albic Soil Under Crop Rotations

Albic soil is a typical low-yield and problematic soil in Northeast China, which severely restricts crop growth and yield. Through a three-year field experiment in the albic soil of China, soil three-phase ratio, soil bulk density (soil BD), soil total porosity (soil TP), size distribution and water stability of soil aggregates, and changes in maize yield under crop rotations were studied. The following three treatments were established: conventional fertilization (T0), conventional fertilization + soil amendment (T1), and conventional fertilization + soil amendment + bio-organic fertilizer (T2). The results indicated that, compared with T0, the soil three-phase ratio deviation value (R) of T1 and T2 decreased by 23.69-74.94%, and the generalized soil structure index (GSSI) increased by 4.75-15.41% in soil layers of 0-20 cm and 20-40 cm. Soil BD and soil TP changed significantly in the soil layer of 20-40 cm under treatment of T2 (decreased 12.82% and increased 18.31%, respectively). Content of aggregates >0.25 mm (R_0.25) increased significantly in the soil layer of 0-20 cm, with increases of 13.71% and 23.21% under treatments of T1 and T2. The mean weight diameter (MWD) and geometric mean diameter (GMD) increased significantly under treatment of T2. Compared with T0, maize yield increased 13.45% and 18.85% under treatments of T1 and T2. Correlation analysis showed that maize yield was significantly correlated with soil physical indexes and aggregate stability. In summary, the combined application of soil amendments and bio-organic fertilizer is not only important for albic soil improvement, but also crucial to stabilize the crop production capacity in albic soil regions.