Life Cycle Environmental Impact Assessment on Different Modes of Greenhouse Vegetable Production in the North China Plain

Abstract

Organic agriculture has a higher potential than traditional agriculture to reduce environmental emissions. However, heavy metals in organic manure inevitably exacerbate eco-toxicity. At present, there are few studies on systematically and comprehensively evaluating the effects of different production modes on the environmental impact of vegetable production in the North China Plain (NCP). The objective of this study is to provide a theoretical direction for reducing the negative impact of greenhouse vegetable production. In this study, we used a greenhouse eggplant production (2013-2016) as case study and conducted a field experiment in Quzhou County, Hebei Province, China. The life cycle assessment (LCA) approach was used to analyze and compare the production and environmental impacts of eggplant production under three modes:conventional, integrated, and organic. The results showed that the potential for water contamination, eutrophication, and soil contamination was high among the three modes, ranging from 82.05% to 84.02%, 10.29% to 12.32%, and 2.62% to 3.48%, respectively. This is occurred mainly in the arable farming subsystem and is attributed to the loss of nitrogen (N) and phosphorus (P), pesticide residues, and heavy metals in organic manure. The environmental impact index of the integrated mode is the lowest, with a value of 0.596, which is 30.3% and 6.7% lower than those of the conventional and organic modes. The integrated mode significantly reduces the emission of pollutants from the greenhouse vegetable production in the arable farming subsystem; therefore, it is the best management practice. In the integrated mode, the environmental costs of producing one ton of eggplant are 46.6 J for energy depletion, 81.9 m2 for land occupation, 0.0046 m3 for water depletion, 0.0054 kg (CO2-eq) for global warming, 0.0060 kg (SO2-eq) for acidification, 0.0735 kg (PO4-eq) for aquatic eutrophication, 2.84E-05 kg (1,4-DCB-eq) for human toxicity, 0.4892 kg (1,4-DCB-eq) for aquatic eco-toxicity, and 0.0174 kg (1,4-DCB-eq) for soil eco-toxicity. Optimizing field management measures such as the application of biological pesticides, using high quality organic fertilizer, and improving the efficiency of N and P use, can better control the negative environmental impacts in the life cycle of vegetable production and improve environmental sustainability in the NCP.