Effects of rice-crayfish coculture on rice yield and food security

Rice-crayfish coculture (RC) refers to an integrated agriculture mode that combines crayfish breeding and rice planting. This mode has developed rapidly in China in recent years owing to its high economic benefits. The effect of large-scale promotion of RC on grain yield has attracted attention. Thus, to explore whether the large-scale popularization of RC has an adverse simultaneous impact on local rice yield and total grain yield, the influence of the proportion of cultivation ditches on rice yield was analyzed, the development status of RC in different regions was compared, and whether RC is suitable for further promotion was investigated. This study analyzed the impact of the RC mode on rice yield through long-term positioning experiments, household surveys in different ecological areas, and statistical yearbook data from Hubei Province over the past 10 years. The results showed the following: 1) RC expanded the area, increased the total yield, and improved farmer enthusiasm for planting rice. There was a significant positive correlation between the RC mode planting area and the rice planting area. The rice-planting area in Qianjiang City, Jingzhou City, and Hubei Province increased by 77.77%, 16.23%, and 12.20%, respectively, and the total rice yield increased by 68.12%, 16.61%, and 20.49%, respectively, in recent 10 years. Simultaneously, the summer grain (wheat) yield in Hubei Province had remained stable over the last 10 years. 2) The average proportion of cultivation ditches of crayfish (G) in the Hubei RC-producing area was 13.42%, and G affects rice yield to a certain extent. Without considering G, the rice yield, when using the RC mode, increased by 17.63% compared to that of traditional rice monoculture. When G≤10%, the RC rice yield was slightly lower than that of traditional rice monoculture, but the difference was not significant. However, under the conditions of 10%<G<20% and G≥20%, rice yield significantly decreased by 18.19% and 34.81%, respectively. 3) There are advantages and disadvantages in RC development areas. The yields of rice and crayfish in Jianghan Plain and the plain along the river in eastern Hubei were better than those on the hills of central and northern Hubei. Previous research results showed that RC can stabilize the yield of rice under appropriate G conditions. Simultaneously, owing to the high economic effect of RC, an increasing number of farmers have joined the industry in recent years, which has promoted an increase in the total yield of rice in the regions. However, there are obvious regional adaptability differences in RC. Only in advantageous regions can give full play to their role in stabilizing grain yield and increasing efficiency. Therefore, the field engineering construction associated with the RC mode should be standardized according to G≤10%, and adhering to the development of RC mode according to local conditions can maintain rice and crayfish income and food security, which is an important guarantee for the sustainable and healthy development of the rice-crayfish industry in China.