Effects of different short-term tillage managements on soil microbial biomass turnover in the double-cropping rice field of southern China

Abstract

Soil microbial biomass were usually regarded as a sensitive indicators in varied of soil fertility and soil quality, and its turnover in paddy field were mainly influenced on by applied with different tillage managements. However, the effects of different short-term (7-years) tillage managements on soil microbial biomass turnover in paddy field under the double-cropping rice system were still need to further investigate. Therefore, the varied of soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN) contents, flux turnover rate of SMBC and SMBN at 0–10 cm and 10–20 cm layers in the double-cropping rice field of southern China with different tillage practices were studied. The tillage experiment set up four treatments: conventional tillage and straw returning (CT), rotary tillage and straw returning (RT), no-tillage and straw returning (NT), and rotary tillage with all straw removed from paddy field as a control (RTO). The results showed that SMBC and SMBN contents at 0–10 cm and 10–20 cm layers in paddy field with CT, RT and NT treatments were significantly increased, compared with RTO treatment. Compared with RTO treatment, SMBC and SMBN contents at 0–10 cm and 10–20 cm layers in paddy field with CT treatment increased by 28.99%, 33.31% and 17.84%, 16.52%, respectively. Flux of SMBC and SMBN at 0–10 cm and 10–20 cm layers in paddy field with CT and RT treatments were significantly higher than that of RTO treatment. This results indicated that flux turnover rate of SMBC and SMBN at 0–10 cm and 10–20 cm layers in paddy field with CT, RT treatments were significantly higher than that of RTO treatment. Compared with RTO treatment, flux turnover rate of SMBC and SMBN at 0–10 cm and 10–20 cm layers in paddy field with CT treatment increased by 65.49%, 39.61% and 114.91%, 119.35%, respectively. SMBC and SMBN contents, flux turnover rate of SMBC and SMBN at 0–10 cm layer were higher than that of 10–20 cm layer in paddy field with the same tillage treatment. Therefore, applied with rotary tillage or conventional tillage and straw returning were beneficial managements for increasing soil nutrient and soil productivity under the double-cropping rice system in southern of China.