设施番茄生产系统的环境影响生命周期评价

应用生命周期评价方法,以陕西省西安市郊区为例,对设施番茄生产系统进行了环境影响评价.结果表明,日光温室和塑料大棚生产1000kg番茄消耗的能源和水资源分别是1740.58 MJ、50.767 m3和1502.346 MJ、53.734 m3;全球变暖潜值(以CO2当量计)、环境酸化潜值(以SO2当量计)、富营养化潜值(以PO3-4当量计)、光化学烟雾潜值(以C2H2当量计)、土壤毒性(以1,4-DCB当量计)、水体毒性(以1,4-DCB当量计)和人类毒性潜值(以1,4-DCB计)分别为271.943 kg、2.151 kg、0.247 kg、0.157 kg、24.217 kg、19.545 kg、0.124 kg和239.163 kg、1.88 kg、0.305 kg、0.109 kg、31.686 kg、19.7 kg、0.304 kg.设施构筑物自身建设和维护带来的主要潜在环境影响是能源耗竭、全球变暖和环境酸化;番茄种植环节引起的主要潜在环境影响是水资源耗竭、富营养化、全球变暖、土壤毒性和水体毒性;农资生产环节的主要潜在环境影响是能源耗竭.设施番茄生产系统中对环境影响大的建材和农资是钢材、聚乙烯材料、氮肥、农药和含过量重金属的有机肥.设施番茄生产系统对环境的影响不容忽视,应展开以降低其环境影响为目标的设施结构与建材、温室内气候条件调控、合理施肥和施药的研究,并对采取的技术方法进行生命周期评价,以确保设施蔬菜的可持续发展.研究结果可为促进设施蔬菜生产系统的可持续发展提供科学依据.

Life cycle assessment of tomato production in greenhouses

Greenhouses provide a facility which maintains a suitable temperature for vegetable growth during the cold season in northern China by using solar radation only. However, additional resources and energy consumption, and the special climate formed in greenhouses may result in various kinds of environmental problems. Most of previous studies had been focused on a specific environmental problem, and few assessed the integrated environmental impact of a solar greenhouse planting system. The integrated environmental impact of tomato production in greenhouses was assessed by using life cycle assessment (LCA) methodology in this study. Primary data were collected from 10 solar greenhouses and 5 plastic greenhouses at suburban Xi'an, China. Tomatoes were planted twice a year at all 10 solar greenhouses, while watermelons were planted in spring and tomatoes were planted in autumn at 5 plastic greenhouses. The environmental impacts of greenhouses construction and maintenance, agricultural materials production, planting period, and the whole greenhouses planting system were analyzed. The results showed that the environmental impact potential of producing 1000 kg tomatoes in solar greenhouses were 1740.58 MJ for energy depletion, 50.767 m³ for water depletion, 271.943 kg for global warming, 2.151 kg for acidification, 0.247 kg for eutrophication, 0.157 kg for photochemical oxidation formation, 24.217 kg for terrestrial ecotoxicity, 19.545 kg for Fresh water aquatic ecotoxicity, and 0.124 kg for Human toxicity, respectively. For plastic greenhouses, these corresponding environmental impact potentials were 1502.346 MJ, 53.734 m³, 239.163 kg, 1.88 kg, 0.305 kg, 0.109 kg, 31.686 kg, 19.7 kg and 0.304 kg, respectively. Although the use of greenhouses made the tomato planting possible during the whole year, its construction and maintenance caused some major environmental problem, such as energy depletion, global warming, acidification and photochemical oxidation formation. Greenhouses also resulted in high temperature, high humidity and a poorly ventilated environment, which was a main cause of serious plant diseases and insect pests in greenhouses. Thus, a large amount of pesticides were used frequently in solar greenhouses. The main environmental problems during the planting period were water depletion, eutrophication, global warming, terrestrial ecotoxicity and fresh water aquatic ecotoxicity. The main environmental problems from the fertilizer and pesticides production were energy depletion. The main materials resulting in environmental problems were steel, polyethylene, nitrogen fertilizer, pesticides and organic manure with excess heavy metal. The environmental impact which was caused by a greenhouse planting system could not be ignored. For a sustainable development of greenhouse planting systems, more studies should be targeted on creating green construction materials and new structure, improving greenhouse climate, regulating fertilizers and water, as well as using green pesticides in order to diminish the environmental impact of the whole system.