Negative External Costs of Pesticides and Their Internalization in the Wheat-Maize Cropping System in China's Northern Plains

When the production or use of a product imposes a cost on a third party, this is referred to as a negative external cost. Negative external costs of pesticides are associated with social costs. However, there is still a lack of a systematic method for evaluating and internalize negative external costs of pesticide. Using the pesticide environmental impact quotient and environmental accounting methods, this study assessed the negative external costs associated with the use of pesticides in a wheat-maize cropping system (WWSM) in China's northern plains and internalized the negative external costs into the market prices of wheat and maize. The results showed that the total negative external costs of pesticide use was 423.9 USD ha-1, which is higher than that of other countries (1.2 to 15.6 times higher). Negative externalities varied significantly according to environmental receptors: applicators accounted for 45% of the total negative externalities, followed by pickers (32%), consumers (11%), groundwater (4.5%), fish (3.9%), beneficial insects (1.7%), birds (1.3%), and bees (1.1%). The negative external costs of maize cultivation were 33% higher than those of wheat cultivation. The application of herbicides resulted in the highest negative external costs compared with fungicides and insecticides. After the internalization of negative external costs, the eco-price of wheat and maize was 0.40 USD kg-1 after internalization of negative external costs. Interestingly, wheat (13%) and maize (18%) exhibited higher eco-price than the current market prices. The positive externalities of pesticide use (1225 USD ha-1) from yield increases were higher than the negative external costs. From the perspective of economic value, the use of pesticides in WWSM generates a positive net externality. In crux, farmers need to use pesticides sparingly with lower ecotoxicity. This study can help farmers to select environmentally friendly pesticides and provide reference for the collection of eco-tax on pesticides