Changes in soil microbial properties with no-tillage in Chinese cropping systems

No-tillage (NT) has revolutionized agricultural systems because it has potential benefits including soil conservation and reduced production costs though saving in fuel, equipment, and labor. Soil quality is of great importance in determining the sustainability of land management systems, and soil microbial properties are becoming increasingly used to assess the effect of farming practices on soil quality due to their quick response, high sensitivity, ecological relevance, and capacity to provide information that integrates many environmental factors. In China, research and application of NT have developed quickly since 1970s. Numerous studies have been conducted in this country to evaluate the effect of NT on soil microbial properties. From these studies, it is evident that NT can lead to an increase in soil microbial size or activity or both and a consequent increase in soil microbial biomass in upland cropping systems. However, there are still several issues that remain unaddressed or inadequately specified. Further investigations are needed (1) to determine the effect of NT on soil microbial diversity by using molecular biological techniques in both upland and rice-based cropping systems; (2) to fully understand the changes of soil microbial properties with NT in rice-based cropping systems, especially for double rice cropping systems; and (3) to clarify the relationship between rhizosphere microbial properties and crop growth in NT rice cropping systems.