Abstract:

To select the most effective microbial product for in-situ decomposition of rice straw under cool conditions in Northeast China, and to determine the optimal dosage of microbial product coupling urea, this study conducted comparative experiments, and used the decomposition rate of rice straw, biological characteristics and yield of rice as indicators to define the optimal microbial product and the dosage of urea. The results showed that the independently developed microbial product NKY showed better field application effects. The straw decomposition rates of Hongqi Farm and Wanchang Town were 68.8% and 67.2%, respectively, which were 38.5% and 35.5% higher than CK. The height, tiller number, and dry weight of rice were also increased, and the rice yield increased by 6.0% and 6.8%, respectively. The optimal dosage for coupling urea with microbial product NKY was 75 kg/hm². Compared with no urea application, the straw decomposition rate increased by 8.7%, and the yield increased by 6.2%. In summary, the microbial product NKY not only has good degradation ability of rice straw, but also could promote crop growth and improve crop yield, which has a better application prospect.

Key words: rice, straw returning, microbial product, decomposition rate, nitrogen application rate, biological characteristics, dry weight, yield