稻田生态系统服务功能的SCM经济评价研究

Paddy rice cultivation with paddy field irrigation has multi-functional roles not only to provide food securely but also to maintain other ecosystem service functions, such as flood mitigation, climate regulation, resolution of organic waste, biodiversity conservation , recreation and amenity and so on. The huge external economic benefits generated by Ecological service functions are often presented by-product of rice. The government and non-agricultural populations consume the public benefits, unconscious or taken for granted, derived from ecosystem services, and unnecessary to pay. This tendency will influence the sustainable development of ecosystem services of paddy. This study is conducted to establish the economic value of the beneficial functions of paddy field ecosystem by substitution cost method, and estimating the economic value of flood mitigation and climate regulation of paddy of jianghan plain, which can provide scientific quantitative decision and reason for different levels government that institute security and benefit farming policy;and enrich and perfect the theory system of Environmental value evaluation;meanwhile, vital realistic significance to safeguard sustainable Food security future.

稻田系统除了提供市场必需的稻米外，还具有洪水防治、气候调节、有机废弃物处理、生物多样性保护、景观形成等多种生态服务功能。这些生态服务功能所形成的巨大的外部经济效果往往以水稻生产副产品的形式出现，政府和非农业人口一直在"消费"这些以公共产品形式存在的生态功能而无需向稻农支付任何额外的补贴或费用，基本上人们对它的消费是无意识的或认为是理所当然的，这种观念极大地降低了水稻生产的重要性，使稻田生态功能的可持续性受到损害。本研究旨在利用替代法（Substitution Cost Method，简称SCM）评价理论与方法建立稻田生态系统服务功能的经济评价系统，并根据该系统以江汉平原稻田为例计算其洪水防治功能和气候调节功能的货币化价值，为各级政府制订稻田生态服务功能的保全政策和惠农政策提供科学的定量决策依据，并丰富和完善环境价值评价的理论体系，对保障我国未来的可持续粮食安全有重要的现实意义。

稻田除了提供市场必需的稻米外，还具有涵养水源、生物多样性保护、气候调节、景观形成、文化教育及保健休养等多种公益功能。本研究利用SCM、市场价值法、影子工程法等评价理论与方法，初步建立了公益功能经济价值评价体系，并对荆州市稻田生态系统的粮食生产、水文循环、气体调节、土壤有机质累积和景观休闲旅游等5个功能的经济价值进行了评价。（1）粮食生产功能：采用市场价值法，得到荆州市稻田生态系统粮食生产的总价值为28.9亿元。（2）水文循环功能：运用影子工程法，计算得到荆州市稻田生态系统早中晚稻涵养水源功能的价值分别为6.6万元、23.1万元、4.8万元，调节小气候功能的价值分别为7.5亿元、38.0亿元、8.2亿元。（3）气体调节功能：运用碳税法、造林成本法等，得到气体调节的总价值为9.0亿元。（4）土壤有机质累积功能：运用影子工程法，计算得到土壤有机质累积的经济总价值为6.52亿元。（5）稻田景观休闲旅游功能：采用条件价值评估法，得到稻田景观休闲旅游人文功能的总产值约为4.4亿元。（6）稻田生态系统总价值荆州市稻田生态系统公益功能的总价值为103亿元，占荆州市当年GDP的7.7%。这一研究结果对稻田公益功能的保全和农业生态补偿标准的制订提供了科学的定量依据，也丰富完善了环境价值评价的理论体系。