Effects of different tillage modes on rain-fed farmland soil microbial biomass and crop indices in Inner Mongolia.

This paper studied the dynamic changes of soil microbial biomass and crop indice s on a degraded rain-fed maize field in the Qingshuihe County of Inner Mongolia under no tillage with low stubble (NL), no tillage with high stubble ( NH), no tillage with low stubble and residues (NLS), no tillage with high stubbl e and residues (NHS), and conventional tillage (CT). No tillage increased the so il microbial biomass C, N, and P, with the sequence of treatments NHSNLSNHN LCT. Except that the soil microbial biomass C in CT had an increase in 10-20 cm soil layer, the soil microbial biomass C, N, and P in all tre atments decreased with soil depth. The soil microbial biomass C, N, and P had th e same seasonal pattern, being the highest in July, secondly in June, and the lo west in October. The LAI in whole growth period varied in unimodal form, while t he plant height and dry matter accumulation were in S form. All the crop ind ices followed the order of NHSNLSNHNLCT. Soil microbial biomass, its P in pa rticular, had positive correlations with crop indices. Our results revealed the advantages of no tillage on rain-fed farmlands in Inner Mongolia.