关键词: 农业生态系统, 脆弱性, 三角图法, 榆林市

Abstract:

Agroecosystem is the premise and foundation of agricultural sustainable development. Under the background of ecosystem weakening caused by global climate change， the research on the vulnerability of agricultural ecosystem is of great practical significance for the formulation of policies for the development of agricultural ecological environment in the future and the realization of sustainable development of agricultural ecosystem. Taking 12 counties in Yulin city as the research unit， 24 indexes are selected from agricultural environment subsystem， production input subsystem and social economy subsystem to construct the agricultural ecosystem vulnerability evaluation system. Combined with ArcGIS 10.2 and Grapher 12 software， the mathematical methods such as weighting method， entropy evaluation method and comprehensive index method are used to study the evolvement characteristics of the vulnerability types of agricultural ecosystem in Yulin city a from 2004 to 2017 in three stages. Four representative starting points of 2004， 2009， 2014 and 2017 are selected as cross-section nodes. And the triangular diagram method is used to analyze the evolvement of the vulnerability types of agricultural ecosystem of 12 counties in Yulin city. The results showed the types of agricultural ecosystem vulnerability in Yulin city were divided into five types from 2004 to 2017： ①Agricultural environment-Production input-Social economy subsystem equilibrium vulnerability type （EPS type）. ②Agricultural environment-Social economy subsystem vulnerability type （PS type）. ③Agriculture environment-Production input-Social economy subsystem equilibrium vulnerability type to Production input-Social economy subsystem vulnerability type to Agriculture environment-Production input-Social economy subsystem equilibrium vulnerability type （EPS-type to PS-type to EPS-type）. ④Agricultural environment-Production input-Social economy subsystem equilibrium vulnerability type to Production input-Social economy subsystem vulnerability type （EPS-type to PS-type）. ⑤Production input-Social economy subsystem vulnerability type to Agricultural environment-Production input-Social economy subsystem equilibrium vulnerability type （PS-type to EPS-type）. The conclusion is as follows： Each subsystem vulnerability degree in various development stages show a distribution pattern： the southern areas are higher than the northern areas， and the 6 southern counties are higher than the 6 northern counties， which is basically the same as the actual development of the agricultural ecological environment in the region. However， the totally regional agriculture ecosystem vulnerability degree presents a trend of decrease year by year，which showes that with the continuous development of social economy， the investment in agricultural production and agricultural science and technology are increasing， the ability of regions to resist the vulnerability of agro-ecosystem is also improved.

Key words: agricultural ecosystem, vulnerability, triangle methodology, Yulin city