作物病害危机下农户新品种采纳行为研究——从个体决策到扩散机制

Study on Farmers’ Behavior of Adopting New Varieties under the Crisis of Crop Disease——from Individual Choice to Diffusion Mechanism

作物病害危机发生的研究情境应重新审视"理性小农"和"生存小农"两大理论传统,诉诸于新的有限知识假设更加贴近研究情境,农户在作物病害危机发生时表现为不确定性下的随机采纳决策和局部遵同效应。本文基于改进的谢林模型和澄迈县蕉农调研数据,采用ABM方法对枯萎病发生情境下蕉农面对两个抗病新品种的采纳决策进行仿真模拟,模型较好地拟合了海南澄迈县蕉农的实际采纳决策进程。研究发现,两个新品种在蕉农群体中的扩散存在"优先接触"效应,最初遭受作物病害的少数蕉农的随机选择,会对两个新品种在蕉农群体中的扩散效果产生影响;"优先接触"效应会经由蕉农社会网络的互动得到放大,最终形成两个新品种在区域上的"隔离"秩序;当两个新品种之一存在显著优势时,两个新品种在蕉农群体中的扩散最终将收敛于优势新品种覆盖所有蕉农的局面。由研究结论提出以下建议,作物新品种在中国农村地区的推广应关注农户知识学习,利用"优先接触"效应占领市场先机,重视农户间的互动,打造优质品种的核心竞争力。

The study on farmers’ adoption of new varieties under the context of crop disease crisis should re-examine the two theoretical traditions including "rational peasant" and "survival peasant" assumptions. This paper proposed the "imperfect knowledge" hypothesis which approximates the practical context of this research, and claimed that farmers would show random adoption decisions and local conformity effects under the uncertainty of the crop disease crisis. Based on the improved Schelling’s model and the empirical data collected from banana farmers in Chengmai County, the ABM method was used to simulate the adoption decision of banana farmers on two new disease-resistant varieties in the scenario of the Panama Disease, and the model was well fitted to the actual adoption decisions of the banana farmers in Chengmai County of Hainan. We find that there is an "exposure priority" effect in the spread of two new varieties among banana farmers. The random selection of a few banana farmers who initially suffered from crop diseases will affect the diffusion result of the two new varieties among banana farmers;The "exposure priority" effect will be amplified through the interaction of banana farmers over their social networks, which eventually resulted in a regional "segregation" order of the two new varieties;when one of the new varieties has significant advantages, the diffusion of the two new varieties among farmers would eventually converge on the situation where the variety with advantage will cover almost all banana farmers. According to conclusions, it is suggested that the promotion of new crop varieties in rural China should concentrate on farmers’ knowledge and learning process, making use of the "exposure priority" effect to seize market opportunities, and understand the interactions among farmers, and enhance the competitiveness of high-quality varieties of crops.