Effects of Short-Term Tillage on Rhizosphere Soil Nitrogen Mineralization and Microbial Community Composition in the Double-Cropping Rice Field.

Abstract

Soil extracellular enzyme plays a vital role in changing soil nitrogen (N) mineralization of rice field. However, the effects of soil extracellular enzyme activities (EEA) and microbial community composition response to N mineralization of rice field under short-term tillage treatment needed to be further explored. In this study, we investigated the impact of short-term (8-year) tillage practices on rhizosphere soil N transformation rate, soil enzyme activities, soil microorganism community structure and their N mineralization function genes in double-cropping rice field in southern China. The experiment consisted of four tillage treatments: rotary tillage with crop straw input (RT), conventional tillage with crop straw input (CT), no-tillage with crop straw retention (NT), and rotary tillage with all crop straws removed as a control (RTO). The results indicated that rhizosphere soil N transformation rate in paddy field in NT and RTO treatments were significantly lower than that in RT and CT treatments. Compared with NT and RTO treatments, soil protease, urease, β-glucosaminidase and arginase activities with CT treatment were significantly improved, as were abundances of soil sub, npr and chiA with CT and RT treatments. Moreover, diversity of overall soil bacterial communities in NT and RTO treatments were significantly lower than that in RT and CT treatments. Soil chitinolytic and bacterial ureolytic communities were also obviously changed combined with tillage and crop straw input practices.