Comprehensive assessment of integrated rice-crayfish farming system as a new paradigm to air-water-food nexus sustainability

Integrated rice-crayfish farming (IRCF) is becoming a popular agricultural production mode and has expanded rapidly in China. However, serious concerns over the ecologically and environmentally friendly development of IRCF are still growing. Despite its importance, there is no comprehensive assessment study of IRCF to evaluate if it is a green and sustainable development in agricultural sector. To address such concerns, the life cycle assessment method at the endpoint level and water footprint were employed to elucidate the potential envi-ronmental risk caused by the fast development of IRCF. Furthermore, the economic assessment was also carried out using cost-benefit analysis. The results showed that, IRCF systems have higher impacts in the human health damage category compared to rice monoculture (RM) systems. This was attributed to the higher direct field emissions such as methane emission and high-water consumption in IRCF. However, IRCF had lower environ-mental impacts in the ecosystem damage category than RM, primarily due to decreased fertilizer inputs. Water footprint was the primary concern in IRCF, with 379% higher water consumption than RM. The expansion of IRCF can affect food security for the following two reasons: i) Outer ridge and ditch that are built around rice fields decrease rice planting area and hence total production, ii) Crayfish occupy rice fields in winter and the following spring, so winter-season crops such as winter wheat cannot be grown in IRCF fields. Economic assessment approved that the gross profit is the main motivation for farmers to shift from RM to IRCF, where 297% higher economic benefit can be achieved. Our results indicated that IRCF expansion improved farmers' income but came with potentially environmental and food security risks. Therefore, strict measures and rational land use planning should be implemented for the sustainable development of IRCF.