Effects of Long-Term Rice-Crayfish Coculture Systems on Soil Nutrients, Carbon Pools, and Rice Yields in Northern Zhejiang Province, China

This research was to examine the impacts of long-term rice-crayfish coculture systems(RS) on soil nutrients, carbon pools, and rice yields in paddy fields , aiming to establish a scientific basis for the sustainable development of RS in the northern region of Zhejiang. The results showed that the change from rice monoculture (CK) to RS resulted in a 24.99% increase in the 5-year average of soil ammonium nitrogen(AN), while the soil nitrate nitrogen(NN), available potassium(AK), and available phosphorus content(AP) decreased by 28.02%, 16.05%, and 28.76% respectively. Moreover, the total organic carbon(TOC), easily oxidizable organic carbon(EOC), dissolved organic carbon(DOC), and microbial biomass carbon(MBC) decreased by 2.45%, 8.82%, 35.31%, and 65.84% respectively. Correlation analysis showed that there was a significant positive correlation between NN, EOC and MBC in the RS. In terms of rice yield, 5-year average of rice yield in RS has decreased by 8.4% compared to CK.The average yield of planting early-maturing varieties of rice was reduced by 13.16%, while the average yield of planting late-maturing varieties of rice was reduced by 6.00%. In conclusion, enhancing water and nutrient management and cultivating late maturing rice varieties are essential strategies for achieving the sustainable development of RS in northern Zhejiang.