城郊有机农场生态系统服务评估——以北京市为例

Abstract

快速城市化对周边农业区域造成巨大影响。都市农业能够提供世界上20%的食品，为粮食安全做出了重要贡献。在全球环境危机的背景下，农业生态保护问题得到了越来越多的关注。有机农场在生产过程中遵循自然规律，不使用化学合成的农药、化肥和生长调节剂等物质，是实现生态农业的有效模式之一。城郊有机农场得益于临近都市的地理位置，常常同时提供参观、采摘等休闲服务，加深了游客对农业的理解和与自然的连结。目前，国内研究大多关注有机食品健康、有机农业政策和环境效益，但往往忽视其提供的经济和文化价值。基于生态系统服务与人类福祉关系的概念框架，以北京市为例，从供给、调节、文化三个方面全面评估城郊有机农场的生态系统服务。结果显示，截至2019年北京市城郊共有271家有机农场，种植面积1.09万hm²，占北京市耕地面积的5.1%。供给服务价值为16.12亿元。调节服务方面，提供了2140万元的土壤碳固存价值，并且比相同面积的常规农场减少了16.4万GJ能量、2639tCO₂、202tSO₂和29tPO₄^3-的排放。文化服务方面，提供了1.189亿元的采摘服务，并促成了120余次农夫市集和50余次讲座、沙龙的宣传教育活动，积累了社会资本。本研究尝试通过直观的数据全面反映城郊有机农场对收益者的多种惠益，凸显了在有限的供给服务之外，城郊有机农场在休闲游憩和教育宣传等文化服务的贡献，为深入理解城郊有机农场生态系统服务提供基础，有助于进一步提高农业管理的精细程度和城市的可持续性。;Rapid urbanization has brought a huge impact on the agricultural areas around city. Urban agriculture can provide twenty percent of the world's food, making an important contribution to food security. Under the background of global environmental crisis, people have begun to pay close attention to ecological protection of agriculture. Organic agriculture follows the natural rules and does not use any chemical synthetic pesticides, fertilizers and growth regulators, so it is one of the effective models to achieve ecological agriculture. Peri-urban organic farms benefit from their proximity to cities, they also can offer some cultural services such as picking, education and so on, which deepen visitors' understanding of agriculture and connection with nature. Based on the conceptual framework of the relationship between ecosystem services and human well-being, this study took Beijing as an example to comprehensively evaluate the ecosystem services of peri-urban organic farms from three aspects, including provision, regulation and culture. The results showed that there were 271 organic farms in the suburbs of Beijing as of 2019, with a planting area of 10,900 hectares, accounting for 5.1 percent of the arable land area in Beijing. The valuation of provision services were 1.612 billion Yuan. In terms of regulating services, organic farms provided 21.4 million Yuan in soil carbon sequestration value, and reduced energy use by 164,000 GJ, 2,639 tons of CO₂, 202 tons of SO₂ and 29 tons of PO₄^3- emissions compared to the conventional farms in the same area. In terms of cultural services, organic farms provided 118.9 million Yuan of picking services, facilitating more than 120 farmers' markets, 50 lectures, salons and other education activities, which accumulated social capital. Urbanization has proceeded rapidly in China, land resources in the suburbs were not only competing with other land uses, but also were subject to various restrictions of ecological management. This study attempts to visualize the number, scale, and spatial pattern of peri-urban organic farms, and assesses the variety of ecosystem services. In particular, we highlight the contribution of peri-urban organic farms to cultural services such as leisure, recreation, education and publicity, in addition to limited provisioning services. The results will provide a basis for deeper understanding of peri-urban organic farms ecosystem services, which can further improve the level of agricultural management sophistication and urban sustainability.