Effects of different tillage modes on soil properties and crop yield in a rain-fed field of Inner Mongolia

A 4-year (2005-2008) field experiment was conducted on a typical slope field in Qingshuihe County of Inner Mongolia to study the effects of no tillage with low stubble (NL),no tillage with high stubble (NH),no tillage with low stubble and residues (NLS),no tillage with high stubble and residues (NHS),and conventional tillage (CT) on the soil properties and maize yield. No tillage increased soil microbial biomass C,N,and P,and soil organic matter and nutrient contents. In 2007 and 2008,the microbial biomass and the organic matter and nutrient contents in 0-10 cm soil layer were in order of NHSNLSNHNLCT. During the first three years of no tillage,maize yield was unstable; but in the 4th year,the yield was increased. Path analysis showed that soil total nitrogen,total phosphorus,available phosphorus,and especially microbial biomass carbon had direct effects on maize yield. The results indicated that no tillage was advantageous to the improvement of soil ecological environment and soil fertility in rain-fed farmlands of Inner Mongolia.