Pesticide overuse in vegetable production: a case study of urban agriculture in city x, China

With the improvement in the living standard and enhancement of awareness of environmental protection by urban residents, food safety issues of vegetables, especially pesticide residues in vegetables, have gradually become an area of focus. According to previous investigations, the problems of pesticide overuse in vegetable production in City X, a typical metropolis of northern China, cannot be underestimated. To figure out the status quo and extent of pesticide overuse in China's urban vegetable production, City X was taken as a research case. Therefore, the main aim of this research is to make an economic assessment of whether pesticides are overused in vegetable production in City X. The study was conducted based on panel data of the inputs and outputs of five kinds of vegetable crops commonly planted in City X from 1990 to 2018. The economic assessment of whether pesticides are overused depends on an accurate estimation of the marginal productivity of pesticides. As we all know, pesticides cannot directly increase crop yields but reduce yield losses by inhibiting pests and diseases and reducing weeds. Therefore, regarding pesticides same as other input factors and introducing them directly into the Cobb-Douglas production function would lead to an inaccurate estimation of the marginal productivity of pesticides. Thus, we adopted a damage control model distributed in exponential and Weibull forms on the basis of the C-D production function to estimate the marginal productivity of pesticides with the NLS method. Subsequently, we calculated the optimal levels of pesticide inputs and evaluated the extent of pesticide overuse for tomatoes, cucumbers, eggplants, peppers, and cabbages cultivated in open-field and greenhouse systems respectively. We found that the marginal productivity of pesticides was close to 0, indicating that pesticide overuse issues on vegetable crops in City X have been extremely serious ever since the 1990s. We also discovered that 100% of our samples suffered excessive pesticide application, and the average pesticide input level was 21.5 to 27.9 times higher than the optimal level. Among the five vegetable crops, the pesticide overuse in tomatoes was the most serious, with actual pesticide input of 2714 yuan/hectare, which was 26.8 to 35.2 times the optimal level. While the extent of pesticide overuse was the slightest for cabbages with 9.7 to 12.8 times the optimal level. Besides, the degree of pesticide overuse for greenhouse vegetables was 55% higher than that of open-field vegetables. Fortunately, our findings suggest that with the implementation of Pesticides Reduction policies in China, the pesticide overuse issue in the vegetable industry in City X, although still grim, has been alleviated. The introduction and application of policies such as unified control, green prevention and control, monitoring, and forewarning have played a great role. With the further refinement and implementation of relevant policies in the vegetable industry, the excessive use of pesticides will be further controlled. Finally, possible policy measures are proposed to ensure the sustainable development of the urban vegetable industry, such as enhancing the publicity and service level of the unified prevention and control policy, utilizing urban agricultural big data, promoting scientific pesticide use knowledge, and new prevention and control technologies by new media, and increasing investment in the R & D of new technologies and new pesticides.