基于演化博弈的中国橡胶主产区目标价格补贴政策及其敏感性研究——以西双版纳为例

当前，橡胶收入不足于吸引农户继续种植橡胶，为保障国家橡胶战略安全，利用演化博弈模型分析了目标价格补贴政策的有效性边界，并对影响目标价格补贴政策的因素进行了敏感性分析。结果发现，依据2019年西双版纳18个样本村的947个截面数据及地区统计公报等测算得出，在橡胶价格为8元/kg时，应将目标补贴价格定位为12.8元/kg；橡胶树单产为影响目标价格补贴额度变量中敏感系数最大的因素；在当前其他因素不变的情况下，橡胶树单产提升10%可使目标补贴价格额度下降25%。建议采取积极稳健的财政补贴政策，利用浮动的目标价格补贴稳定橡胶产区的农户预期，同时辅以橡胶价格保险等配套政策激励农户提高橡胶树单产，在达到政策目标的同时降低财政成本。

The Target Price Subsidy Policy and Its Sensitivity in the Main Rubber Producing Areas in China Based on an Evolutionary Game: A Case Study of Xishuangbanna

At present, rubber income is insufficient to encourage farmers to continue to plant rubber. Rubber farmers' forced cutting, abandonment, and malicious destruction of rubber trees have destroyed a large number of rubber forests, causing rubber production to drop sharply; natural rubber incentive policies such as seedling subsidies have not been effective in addressing this. If short-term policies remain weak, it is very likely that rubber production will reach a crisis in the next five to eight years. Policies are thus needed to ensure the safety of the national rubber strategy and to formulate the target subsidy price for natural rubber scientifically, as well as to slow down the rate of labor transfer from the rubber industry to other industries, while gaining trial time for the application and promotion of new technologies. Based on 947 pieces of cross-sectional data and regional statistical bulletins of 18 sample villages in Xishuangbanna in 2019, this study analyzes the validity boundary of the target price subsidy policy using an evolutionary game model and investigates the sensitivity of factors that affect the target price subsidy policy. 1) This study tests the effectiveness of the target price subsidy policy by establishing an evolutionary game model of "subsidy policy-farmer behavior." When the subsidy amount is less than 4.8, there is no evolutionary stable point in the game system, based on the 2019 data. Thus, the target price should be 12.8 yuan/kg when the rubber price is 8 yuan/kg, and farmers will then be expected to fully adopt the strategy of planting rubber. This target price can stabilize the expectations of farmers in rubber production areas and restrain farmers from reducing the scale of rubber planting. Based on this preliminary estimate, the unit cost of the target price subsidy policy is 5,400 yuan/(hm²·a^-1), and Xishuangbanna thus needs about 1,485 million yuan/a to maintain the target of 275,000 hm². 2) A single factor analysis method is adopted to calculate the sensitivity coefficient. Through the sensitivity analysis of the four factors of per capita disposable income of rural residents, rubber tree yield, planting cost, and dry rubber price in the game model, it is found that the corresponding financial subsidy cost will also decrease when the rubber price rises. Among the four factors that affect the target subsidy price, the sensitivity coefficient of the rubber tree yield is the largest, constituting a sensitive factor. When the planting cost and dry rubber price remain unchanged, as the yield of rubber trees increases from 2.5 kg to 2.75 kg, the target subsidy price amount drops from 5.7 yuan/kg to 4.4 yuan/kg, and the subsidy amount drops by 22.81%. The promotion of the target price subsidy policy may lead to greater financial pressure, thus, increasing the yield of rubber trees is a necessary coordinated measure.,and the natural rubber futures price insurance project will also help reduce fiscal costs while achieving policy goals. This study answers the question of how to determine the target subsidy price of natural rubber scientifically, and provides a basis for decision-making and significant guidelines for formulating scientific and effective rubber industry incentive policies.