Assessment of the functions and ecological services values of green manure in paddy fields in South China

In the context of deepened promotion of rural revitalization, exploration of greener and more ecological path to agricultural modernization has become the mode of deepening agricultural reform. In the process of building modern agriculture, China has led the establishment of good agricultural ecosystems as a breakthrough point and the development of green manure as an important starting point in the establishment of good agricultural ecosystems and promotion of green transformation of agriculture. In order to explore ecological services values of green manure (Astragalus sinicus L.) in winter paddy fields in South China, we defined ecological services functions of green manure in paddy fields in winter and used research methods (such as actual market method, alternative market method and virtual market method) to construct an initial theoretical model of ecological services value assessment from which ecological services values of green manure in South China were calculated. The following conclusions were reached:1) that ecological services functions of green manure in paddy fields in South China were mainly of 2 kinds-regulation and support services. Regulation services included gas regulation, water conservation and soil conservation. The support services included accumulation of soil organic matter and soil nutrient cycle, corresponding to ecological services values defined for the above 5 species. 2) For a rotation cycle, ecological services value of winter green manure in paddy fields in South China was 1.13×10⁴ ￥·hm^-2. Among these, the value of gas regulation was the largest (3.80×10³ ￥·hm^-2), the cumulative value of soil organic matter followed next (2.79×10³ ￥·hm^-2), next were nutrient cycle (2.04×10³ ￥·hm^-2) and soil conservation (2.14×10³ ￥·hm^-2) values, and soil water conservation value was the smallest (4.80×10² ￥·hm^-2). 3) The cost of winter green manure was 1.73×10³ ￥·hm^-2 in paddy fields in South China. The ecological services value of green manure was 6.5 times the cost of planting, indicating that the existence of ecological services value of green manure was objective. This study provided further detail on scientific methods and the basic parameters for ecological services value assessment for green manure in paddy fields in South China. Meanwhile, it also provided the theoretical basis for the formulation of ecological compensation mechanisms for future green manure plantations.