A comparative analysis of ecosystem service values from various rice farming systems: A field experiment in China

Integrated farming systems in paddy fields are being widely adopted for water-food-energy nexus in China. The mechanisms of these integrated farming systems and their economic and ecological benefits have been studied, however, investigation on their ecosystem service values (ESVs) remains limited in the field. To address this gap, this study comparatively analyzed the ESVs of rice monoculture, rice-fish co-culture and rice-fish-water spinach co-culture through a field experiment during the early and late rice growing seasons in 2022. Six positive ESVs including the primary product supply, CO₂ fixation, O₂ release, soil organic matter accumulation, flood control and water storage, soil nutrient maintenance, and one negative ESV of greenhouse gas (GHG) emissions were investigated and evaluated. The highest total positive ESV was approximately 50,200 US$/ha/yr of the rice-fish-water spinach co-culture, which was 31.4% higher than that of the rice monoculture, and the total primary products value increased by more than two folds than that of the rice monoculture. The total ESVs of the rice-fish co-culture resulted in approximately 43,700 US$/ha/yr, which was 14.4% higher than that of the rice monoculture of 38,200 US$/ha/yr, and the total primary products value increased by 63% as compared with the rice monoculture. Subtracting the negative value of GHG emissions, the net ESVs was approximately 49,400 US$/ha/yr of the rice-fish-water spinach co-culture, followed by 42,900 US$/ha/yr of the rice-fish co-culture, and 37,600 US$/ha/yr of the rice monoculture. Our findings suggested that it should be encouraged to adopt good integrated farming systems for better ecosystem services in paddy fields and to promote the decision makers’ and the public awareness on ecological farming, and field experiments are warranted to explore more practical co-culture systems and to optimize and maximize economic and ecological benefits as well as ecosystem service functions.