Effect of a urea and urease/nitrification inhibitor combination on rice straw hydrolysis and nutrient turnover on rice growth

Abstract

Stabilized fertilizers that contain nitrification inhibitors and/or urease inhibitors are widely used in China. A pot experiment was conducted to analyze soil enzymatic characteristics related to carbon and nitrogen turnover and metabolism under the use of rice straw and stabilized fertilizer. Results showed that stabilized fertilizer exhibited the highest yield production, panicle numbers, and above-ground biomass. Compared with urea treatment with straw, adding inhibitors reduced soil organic carbon and the enzyme activity related to acquisition of carbon, but increased soil organic carbon accumulation, rice yield, and above-ground biomass. Stabilized fertilizer increased protease activity; however, it decreased N-acetyl-β-glucosaminide. Addition of straw significantly increased dissolved organic and microbial biomass carbon or nitrogen, as well as the enzyme activities of α-D-glucosidase, β-D-glucosidase, β-N-acetyl-glucosidase, and cellulase at the seedling and tillering stages. The principal components analysis showed that the synthesis of extracellular enzyme related to carbon and nitrogen acquiring act as a proxy for straw decomposing under nitrogen conditions. The combination delayed the release of ammonia, which affected the carbon and nitrogen coupling by microbial organisms. These results demonstrated a relationship between soil carbon and nitrogen dynamics and soil enzymes in different fertilization management.

Effects of mild alternate wetting and drying irrigation and rice straw application on N2O emissions in rice cultivation

“…Straw (S) return to the field is a valuable measure for improving SOM (Huang et al, 2021), and it is beneficial for reducing the environmental pollution caused by burning straw or discarding it randomly (Wang et al, 2018). In addition, rice straw return may cause changes in paddy field GHG emissions (Naser et al, 2007;Ye and Horwath, 2017;Sun et al, 2018;Yu et al, 2021), N-use efficiency (Liu et al, 2021), and rice yield (Chen et al, 2016;Ku et al, 2019). Although there have been many studies on mild paddy AWD irrigation or rice straw return, few studies have focused on the effects of mild AWD irrigation combined with rice straw return on rice cultivation.…”