The implementation of rice-crab co-culture system to ensure cleaner rice and farm production

The traditional co-culture systems have attained the attention for better production, still have gaps to identify key factors influencing the safe grain production, yield enhancement, and economic viability. Here, a field survey and a field experiment was conducted in Panjin city, including two production systems: rice-monoculture (RM) and RC system. The treatments of field experiments were: rice-monoculture (RM), 3000 crabs ha- 1 without feed (RC3000), 6000 crabs ha- 1 with feed (RC6000), and 12000 crabs ha- 1 with 2 x feed (RC12000). During field survey, higher number of crabs reduced the number of productive tillers while, the productive traits were improved significantly except 1000-grain weight was insignificant. Field experiment indicated that suitable stocking density and feed management has no negative effect on agronomic or productive trait. Grain yield was improved (19.9%) in RC3000, (22.0%) in RC6000, and (14.7%) in RC12000 as compared to RM. The reduction in shrivelled grains spike- 1, and the increase in filled grains spike- 1, seed setting percentage, and 1000-grain weight in RC system improved the rice production. Grain nitrogen, phosphorus, and potassium contents were also improved by RC6000. Farm income and benefit-cost ratio were higher in RC system, meanwhile, the maximum farm production (16231-yuan ha- 1) and benefit-cost ratio (0.51) were in RC6000. The RC system can control drained out water nutrients concentrations, which helps in water pollution control. The results suggested that RC system improves the clean grain and farm production, resource utilization, and the economic status with managed optimum stocking density and feed.

Automated summary

The study found that suitable stocking density of crabs and proper feed management can increase rice yield, improve grain quality, raise farmers' income, and play a role in controlling water pollution.