Effects of Short-Term Tillage on Rhizosphere Soil Nitrogen Mineralization and Microbial Community Composition in 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 microbial community structure, and the N mineralization function gene abundances 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 straw removed as a control (RTO). The results indicated that the rhizosphere soil N transformation rate in paddy field under the NT and RTO treatments was significantly decreased compared to RT and CT treatments. In comparison to the NT and RTO treatments, soil protease, urease, β-glucosaminidase, and arginase activities were significantly improved by the CT treatment, as were abundances of soil sub, npr, and chiA with CT and RT treatments. Moreover, the overall diversity of soil bacterial communities in NT and RTO treatments was significantly lower than that in RT and CT treatments. Soil chitinolytic and bacterial ureolytic communities were also obviously changed under a combination of tillage and crop straw input practices.