Abstract: Resource utilization and livestock waste management are two important aspects of sustainable agriculture in China, especially in the agricultural non-point source (NPS) pollution. In order to analyze the influence mechanism of NPS pollution, this study proposes a two-party evolutionary game model to characterize interactions between local governments and farmers. Firstly, we obtain the optimal strategies of local governments and farmers by a theoretical analysis, and then numerical simulations are applied to assess the impact of various factors on strategy selection. A comprehensive evaluation of government incentives and environmental regulations is carried out to find a balanced approach to environmentally sustainable agriculture. Analytical results reveal that environmental and economic factors significantly affect the local government’s decisions, with economic considerations exerting a more pronounced influence. An increase in the environmental quality index coefficient motivates farmers to actively manage NPS pollution, while an increase in the economic index coefficient disincentivizes farmers to do so. Changes in local government spending have a more substantial impact on local government than farmers, who adapt their strategies in response to government actions, albeit with a time lag. Reducing local government operational costs improves the likelihood of farmers actively engaging in NPS pollution control. If the local government increases penalties to tighten its control over pollution-related activities, it contributes to higher revenue. Imposing a penalty limit constrains the strategy space of both parties, thereby facilitating optimal equilibriums in the game. However, more government subsidy affects regulatory actions, which may prove ineffective if it fails to cover pollution control costs. Obviously, it is always a challenge to reach an optimal strategy. Prudent incentive policies are the main means for guiding both the local government and farmers towards an appropriate equilibrium.
This study offers the following managerial insights: (1)Enhancing local government performance assessment standards by progressively emphasizing environmental quality metrics. Prioritizing the evaluation of rural environmental quality during local government tenures. Considering reducing the weight of economic development indicators in these assessments and reward local governments effectively by balancing environmental and economic factors through optimized agricultural production methods. (2)Establishing an environmental supervision system to control agricultural NPS pollution. This system should engage local environmental public interest organizations and public participation in improving feedback, information sharing, and incentive mechanisms for local government interactions with the public. It will reduce the supervisory costs incurred by local governments. (3)Actively guiding farmers for reducing fertilizer and pesticide usage while raising awareness of agricultural NPS. Promoting environmentally friendly agricultural practices to optimize the rural environment through modified planting and breeding methods, operational techniques, and management models. (4)Employing macroeconomic control measures to institute rational incentive systems and corresponding penalties. Ensuring the regularity and institutionalization of local government oversight and inspection activities while enhancing the efficiency of detecting agricultural NPS pollution. These actions are essential for advancing sustainable development of rural ecological environment.

Key words: two parties, agricultural nonpoint source pollution, evolutionary game, behavioral decision, numerical simulation

摘要： 农业面源污染已成为制约我国农业可持续发展的重要因素,为了有效剖析其内部影响机理。本研究从地方政府与农民两大博弈主体的行为互动入手,在假设参与主体均为有限理性的前提下,将进化博弈理论应用于地方政府与农民,构建了双方的演化博弈模型,通过分析双方的复制动态方程,得到了两种稳定的演化策略,并进行数值模拟分析,探讨博弈双方的策略稳定性以及各因素对策略选择的影响。研究得出:经济系数权重对地方政府策略选择的影响大于环境质量权重,并且权重提升对农户策略选择产生的影响效果不同;减少地方政府监管成本支出有利于提升农户积极治理农业面源污染的概率;地方政府对农户的处罚与激励都会对农户决策产生影响,但是合理的政策才能使地方政府与农户偏向最优均衡。

关键词: 两方, 农业面源污染, 演化博弈, 行为决策, 数值仿真