ABSTRACT

Evaluating soil quality is of vital importance to strategize fertilization and management practices for sustaining agricultural productivity. Five fertilization practices were carried out for 6 years under corn-soybean rotation in Mollisols of Northeast China. Two soil quality index models of Nemoro quality index (NQI) and integrated quality index (IQI), and two indicator selection approaches of total data set (TDS) and minimum data set (MDS) were applied for evaluating changes in soil quality index. NQI-MDS, NQI-TDS, IQI-MDS, and IQI-TDS approaches all indicated that six-year crop straw returning and dairy manure application under corn-soybean rotation increase soil quality index at 0–30 cm soil depth. Depended on soil-depth, IQI-MDS is the most suitable soil quality model for evaluating soil quality at 0–10 cm and 10–20 cm, and NQI-MDS at 20–30 cm soil depth. Soil quality index in IQI-MDS at 0–10 cm soil depth is the method to evaluate soybean yield. Integrating crop yield and soil quality index, the six-year organic amendments, especially dairy manure application is the most suitable management practice in promoting soil biochemical, chemical and physical properties under corn-soybean rotation in Mollisols.