Evaluation of Ecosystem Services Provided by 10 Typical Rice Paddies in China

Abstract

Abstract: Based on reference review, this study investigated ecosystem services supported by 10 typical rice paddies in six rice planting regions of China. The services were primary production, gas regulation, nitrogen transformation, soil organic matter accumulation, and water regulation and flood control. The results indicated that grain production of the 10 rice paddies was between 4.71 and 12.18 t ha-1 y-1; straw production was 4.65 to 9.79 t ha-1 y-1; gas regulation was calculated to emit O2 ranging from 8.27 to 19.69 t ha-1 y-1 and to assimilate greenhouse gases ranging from -2.13 to 19.24 t ha-1 y-1 (in CO2 equivalent); nitrogen transformation was estimated as nitrogen input ranging from 209.70 to 513.93 kg N ha-1 y-1 and nitrogen output of 112.87 to 332.69 kg N ha-1 y-1; soil organic matter accumulation was calculated to be between 0.69 and 4.88 t C ha-1 y-1; water regulation was estimated to consume water resources of 19875 m3 ha-1 y-1 and to support water resources of 6430 m3 ha-1 y-1; and flood control of several of the rice paddies was calculated to be 1500 m3 ha-1 y-1. The integrated economic value of ecosystem services of these rice paddies was estimated at USD 8605-21 405 ha-1 y-1, of which 74%–89% of the value can be ascribed to ecosystem services outside primary production. The results also indicated that the integrated economic value of the ecosystem services of the 10 rice paddies was higher when nitrogen fertilizer was applied in the range of 275 to 297 kg N ha-1. Until now, the economic value of the rice paddy ecosystem has been underestimated as only the economic value of grain and straw production was previously calculated. As more and more forest land and grassland is lost to urban and industrial use, cropland and especially rice paddies, will become more ecologically important to society. The economic value of ecosystem services supplied by rice paddies, outside primary production, are worthy of increased research attention.