## 1 Introduction  
The 19 th National Congress of the Communist Party in China pointed out that the construction of an ecological civilization is a millennium plan for the sustainable development of the Chinese nation, and we should treat the ecological environment as life [1]. According to the 2020 census, 500 million people in China are in rural areas. The issue of agricultural and rural farmers is a fundamental issue related to both the national economy and people's livelihoods. China always adheres to a strategy of rural revitalization and has made some achievements in the construction of modern agricultural industrial systems, production systems and management systems [2]. However, to increase the production and income of farmers, the use of agricultural film, pesticides and chemical fertilizers is increasing annually, which leads to an increase in agricultural carbon emissions [3, 4]. From 1993 to 2008, the use of agricultural film, pesticides and chemical fertilizers led to an increase in agricultural carbon emissions from 366.23, 416.93 and 2822.84 million tons to 1039.63, 824.98 and 4692.04 million tons, respectively, with average annual growth rates of 7.20%, 4.65% and 3.45%, respectively [5]. Subsequently, some scholars have used agricultural film,pesticides and chemical fertilizers as agricultural materials to measure the overall impact on agricultural carbon emissions from 2005 to 2019 [6]. The problem of agricultural pollution cannot be ignored. Agricultural development should not only pursue the economic benefits brought by agricultural film, pesticides and fertilizers but also consider the environmental problems they bring. Agricultural film is an important means of agricultural production. The advantages of the use of agricultural film in agricultural development are mainly reflected in the fact that it can increase crop yields, improve product quality and enrich the supply structure of agricultural products [7]. Agricultural film is mainly trellis film and ground film, in addition to shade net, insect net, forage film and agricultural non-woven fabric, etc. In 2019, China's agricultural film usage is still dominated by ground film, with ground film use accounting for 57.27% of agricultural plastic usage. The use of trellis film and other agricultural films for fruits and vegetables, etc. accounted for the remaining 42.73% [8]. The use of agricultural film has a great impact on the agricultural ecological environment, causing the soil environment to be seriously polluted by microplastics [9; 10]. The microplastics not only destroy soil structure, which is not conducive to the movement of water in the soil and the exchange of soil gas [11; 12], but also affect the microorganisms in the soil [13]. According to the Bulletin of the Second National Census of Pollution Sources, the use of plastic film reached 1,419,300 tons in 2017, and the accumulated residual amount for many years was 1,184,800 tons, causing serious nonpoint source pollution such as that of water and soil. The problem of residual pollution of agricultural film in China is becoming increasingly serious [14] and restricts the green development of agriculture. Agricultural economic benefits are the livelihood of rural residents. Increasing the production and income of farmers has always been a topic of concern for governments at all levels [15]. We need to fully understand the impact of agricultural film on agricultural development so that we can accurately grasp the evolution law of agricultural film pollution in agricultural development and formulate suitable agricultural nonpoint source pollution control policies. Promoting the green development of agriculture is the only way to achieve rural revitalization [16]. The innovation of this paper is to use the panel threshold regression model and take the agricultural film as the threshold variable to study the nonlinear impact of agricultural film, pesticide and fertilizer on agricultural development under different threshold values.