【作者】 陈娟；

【导师】 南灵；

【作者基本信息】 西北农林科技大学 ， 土地资源管理， 2013， 硕士

【摘要】 改革开放以来，伴随着经济增长、城镇化水平不断提高，大量土地从农业部门转移到非农产业部门，这一方面支撑了国民经济的全面发展，另一方面却造成了土地资源的大量损失，即所谓的农地非农化趋势。农地非农化为我国经济快速发展提供了宝贵的土地要素的同时，农地非农化也会生态环境产生影响，带来生态的负外部性，降低了土地生态系统的服务功能，损失了部分的生态系统服务价值。由于负外部性的问题，造成边际社会成本大于边际私人成本，而市场机制难以对外部性问题产生作用，使得多出的这部分成本难以得到补偿或者说难以记录到国民生产总值当中。土地是最为宝贵的自然资源之一，并因其用途变更的困难性，农地非农化更应该慎之又慎。因此这就需要在农地非农化产生的生态风险级别与减少风险成本之间进行权衡，协调发展与环境问题，为可持续额发展提供有力的保障，风险管理提供重要的决策依据。为此本文在分析陕西省及陕北、关中和陕南地区的农地非农化情况的基础上，按照美国EPA在1998年发布的生态风险评估框架对陕西省以及陕北、关中和陕南地区的农地非农化生态风险的风险源、风险受体和生态终点进行分析，并建立了农地非农化生态风险评估的指标体系，将生态风险划分为5个等级，采用层次分析法和模糊综合评价法进行实证分析。根据研究表明：得出陕西省的农地非农化主要是耕地非农化，其次是园地非农化，而其他类型农地的非农化仅占总的农地非农化的很小的一部分。陕西省内部，陕北、陕南、关中三大区域之间的农地非农化差异很大，关中地区的农地非农化占全省农地非农化的65.79%。对于不同类型农地的非农化，差异也很大，关中地区的耕地非农化和园地非农化占全省的72.87%和91.91%，陕北地区的林地非农化和牧草地非农化占全省的61.66%和89.91%。农地非农化在各大区域内的情况也是不同的，关中地区和陕南地区农地非农化的主要来源于耕地，都占到各自总的非农化面积的80%以上，陕北地区农地非农化的主要来源于林地。陕西省农地非农化造成的生态风险处于中等风险水平；陕南地区的农地非农化对生态环境的影响处于较高的风险水平；陕北和关中地区的农地非农化造成的生态风险则处于较高的生态风险水平。经分析发现：陕北和关中地区农地非农化的生态风险都处于较高的风险等级上，其成因是不同的，由于大部分的农地非农化都发生在关中地区，农地非农化面积越大，产生的生态风险有可能越大；陕北地区由于自身的生态环境较为脆弱，农地非农化活动一旦发生则比其他地区造成的生态后果严重，产生的生态风险就越大。而陕南地区由于自然生态环境状况较好，且农地非农化面积较小，因此陕南地区由于农地非农化造成的生态风险则较小。更多还原

【Abstract】 Since reform and opening up， along with economic growth and urbanization levelimprovement. A lot of farmland from agricultural sector transfers to other sectors. On the onehand， farmland conversion delivers precious land element. On the other hand， farmlandconersion has an bad affect on the environment. Farmlad conversion also brings negativeexternalities and reduce the ecosystem service function. Because of the negative externalityproblems， marginal social cost is bigger than marginal private cost. Market mechanism isdifficult to have an effect on negative exteralities，this part of cost is difficult to make up andrecord to the GDP. Farmland is one of most valuable natural resources and is hard to changeits usage， we should be more careful to change farmland uses. We need banlance betweenreducing risk costs and the ecological risk of farmland conversion. Ecological risk assessmentof farmland conversion provides strong guarantee for the sustainable development andimportant basis of risk management.On the basis of analysis the situation of farmland conversion in Shaanxi province andguanzhong region， shanbei region and shannan region， analyse the risk source， riskreceptor and ecological endpoint of farmland conversion in Shaanxi province and guanzhongregion， shanbei region and shannan region. Build ecological risk assessment indicatorsystem for farmland conversion， divide the ecological risk into5grades. Use analytichierarchy process(AHP) and fuzzy comprehensive evaluation method for emprical analysis.According to the study， farmland conversion is mainly cultivated land conversion inShaanxi province， then garden land conversion， and other types of farmland conversionaccounts for only a small part. There are great differences dring guanzhong region， shanbeiregion and shannan region. Farmland conversion in guanzhong region accounts for65.79%offarmland conversion in Shaanxi province. Different types of farmland conversion havedifferences， cultivated conversion and garden plot conversion in guanzhong area is theprovince’s72.8%and91.9%， forest land conversion and grass land conversion in sahnbeiarea is the province’s61.66%and89.91%. The situation of farmland conversion is differentin different areas， farmland conversion of guanzhong area and shannan area mainly comesfrom cultivated land， the farmland conversion of shanbei area comes from forest land conversion. Ecological risk in Shaanxi province caused by farmland conversionis in mediumlevel. Farmland conversion in shannan area caused ecological risk is in low level. Farmlandconversion in shanbei area and guanzhong area caused ecological risk is in high level.Through the analysis found that， shanbei and guanzhong’s ecological risk level are at ahigher level， and there are different resons. As most of the land conversion occurs in theguanzhong area， farmland conversion area is lager， the ecological risk is greater. Shanbeihas a fragile ecological envirenment， farmland conversion causes a serious consequencethan other areas， and ecological risk is more bigger. Shannan has a good ecologicalenvirenment and farmland conversion area is lesser， ecological risk in shanbei area casuedby farmland conversion is lesser.更多还原