Rice-crab coculture to sustain cleaner food production in Liaohe River Basin, China: An economic and environmental assessment

Abstract

Irrational rice planting–breeding modes may result in serious ecological and environmental issues and unsustainable agriculture. In this study, economic benefits combined with emergy analysis were used to evaluate the environmental and economic performances of three rice production modes, namely, rice monoculture (RM), conventional rice-crab (CRC) and optimized rice-crab (ORC) modes, in Panjin City surrounding Liaohe River Basin in Northeast China. Rice and crab yields of ORC were increased by 8%–12% and 9% compared with those of RM and CRC modes, respectively. The value-to-cost ratio, economic benefits density and benefit-cost ratio of ORC increased by 46%–51%, 55%–80% and 59%–66%, respectively, compared with those of RM and CRC modes. The results of emergy analysis indicated that the production efficiency of ORC mode increased by 21%–45% compared with that of CRC mode according to the unit emergy values though slightly lower than that of RM mode. Compared with those of RM and CRC modes, renewable fraction and emergy sustainability index increased within the ranges 7%–28% and 4%–36%, respectively, and environmental loading ratio decreased by 9%–34%,. Considering ecological and economic effects, ORC mode was conducive to improve the sustainability and economic viability of rice production in Liaohe River Basin. Labor and service, fertilizer utilization, and forage input play an important role in emergy investment structure among the three modes, thereby suggesting that appropriate allocation of labor should be implemented to improve the labor efficiency and government should increase subsidies for fertilizer and agricultural machinery. Moderate industrial integration and large-scale operation modes, efficient utilization of local resources, whereas reducing external inputs are suggested to considerably improve the environmental performance and sustainable development capacity of the rice planting–breeding mode.