稻鸭共作系统生态服务功能价值的评估研究

Estimation of Ecological Services Value for the Rice-Duck Farming System

采用生态经济学的方法,对稻鸭共作稻田系统的农产品生产、大气调节、涵蓄水分、土壤有机质积累与营养元素保持的生态服务功能价值进行了估算和综合分析。结果表明,稻鸭共作系统生态服务功能的价值量为18104.82元/hm2,比常规稻作系统高15.64%左右。其中,稻鸭共作系统物质生产的功能价值为6720元/hm2,所占比例为37.12%;环境调节功能价值量为11384.82元/hm2,主要表现为调节大气、土壤养分积累与营养元素保持,两者对环境调节功能价值的贡献率可达77.48%。而常规稻作系统的环境调节功能主要表现为调节大气,单项所占的比例为65.34%。稻鸭共作与常规稻作系统涵蓄水分功能的价值对环境调节总功能价值量的贡献率相差不大,分别为14.16%和17.60%。稻田养鸭兼顾了控制农田生态系统的温室效应、维持和保育土壤肥力等,更有利于稻田系统各项生态服务功能的充分发挥。

The culture of ducks in rice fields is a 1ong-standing traditional integrated farming practice in China.There has been a wide variety of studies on ecological and economic benefits from raising duck in rice fields,such as decreasing harmful pesticides and chemical fertilizers,a high efficacy in nutrient recycling,and high and diversified production.To further explore benefits relevant to humans from the rice-duck integrated farming system,the ecological services function such as agriculture productions,gas regulation,water conservation,soil organic matter accumulation and main nutrient elements maintenance were identified and analyzed on the basis of principles of ecological economics and relevant theories of value ecosystem services.Assessment approaches such as the law of cost,law of cost of the chance and project law of the shade were applied to measure service function value of the rice-duck ecological system.Results showed that total ecological services value of the rice-duck farming system was roughly 18104.82 yuan per hectare,about 15.64%higher than that of the conventional rice cropping system.For the rice-duck farming system,agricultural production and gas regulation function value was 6720 and 5928.72 yuan per hectare,accounting for 37.12%and 32.75%of the total ecological services value, respectively.Water conservation function value in the rice-duck integrated system was found to be the lowest,merely accounting for 14.16%of the total ecological services value.Services value of soil organic matter accumulation and main nutrient elements maintenance in the rice-duck farming system amounted to 2892.40 yuan per hectare,about 3.2 times of that in conventional rice farming systems.Comprised mainly of gas regulation,soil organic matter accumulation and main nutrient elements maintenance,environmental regulation function services value in the rice-duck farming system and conventional rice farming system was estimated to be 11384.82 and 9885.62 yuan per hectare,respectively,about 1.69 and 1.84 times more than agriculture production value. Consequently,it can be concluded that the paddy rice culture provides not only steady yields of grain production function but also significant environmental regulation services function.Effective in controlling greenhouse gas effects as well as conservation of soil fertility and quality,duck culture in rice cropping fields could be more conducive to improving ecological and economic benefits of the paddy rice system.Even though certain disagreement regarding the environmental and economic value of agro-ecosystem services exists because of the lack of evaluation methods and variations in the cropping system,this study would be helpful to assist in making decision on improvement of sustainable rice production technologies,strategic plans as well as policies for regional agricultural development.