Formulation of soil quality index plus to support soil management in preventing soil degradation in dryland farming

Abstract Soil degradation threat to achieving sustainable agriculture is very prominent, especially in tropical areas like Indonesia. Soil degradation is a process of decreasing the function, quality, and productivity of the soil. Therefore, a soil management technique is needed to prevent soil degradation. The crucial problem faced is the unavailability of instruments and methods to assess and monitor soil quality and provide direction in maintaining the soil from soil degradation. Soil types and land suitability classes systems cannot assess soil quality and soil degradation due to land and soil management. Besides, both of the systems are not sensitive and satisfactory to evaluate changes in soil quality and soil degradation. The purpose of this study was to develop Soil Quality Index Plus (SQI-Plus) to evaluate soil quality in supporting development of soil management techniques, monitoring and evaluation of soil quality, and providing recommendations for maintaining soil quality to prevent soil degradation. SQI-Plus is presented in numerical forms and followed by letters which indicating one or more limiting factors for plant growth and production which needs to be repaired or rehabilitated to achieve optimal production and preventing soil degradation.