【摘要】 为更好地探究延安市退耕还林前后土地利用变化对区域土壤保持生态服务功能的影响,采用了InVEST模型对延安市退耕还林前后2000年和2015年的土地利用变化及土壤侵蚀量、土壤保持量进行了评估,该模型在计算生态系统土壤保持服务功能时,考虑了地块泥沙输移、沉积这一重要水文过程,在计算土壤保持量时更为精确。结果表明:(1)15年间各地类面积均发生了不同程度的变化,其中林地面积的增加量(主要来源为耕地和草地)和耕地面积的减少量(主要流向为林地和草地)分别达到了3 142.25km2及3 011.27km2,退耕还林工程取得了巨大成效。(2)延安市2000年和2015年的土壤侵蚀强度均以轻度和中度侵蚀为主,侵蚀总量分别为2.20亿t和1.38亿t,15年间各侵蚀强度类型均有向低等级侵蚀强度类型转换的趋势。(3)延安市2000年与2015年土壤保持总量分别为7.72亿t和8.50亿t,且土壤保持量呈东北向西南增加的趋势,各地类中林地和草地的土壤保持效果最佳,说明退耕还林工程的推进是增加区域土壤保持功能的重要途径。更多还原

【Abstract】 To better explore the effects of land use change on ecosystem service of regional soil conservation before and after Grain for Green Project(GFGP)in Yan′an,the InVEST model was used to evaluate the change of land use,soil erosion and soil retention from 2000 to 2015.The model took into consideration of such important hydrological processes as sediment delivery and deposition when computing soil conservation,therefore,it is accurate in terms of soil retention.The results showed that:(1)over the past 15 years,all types of land use underwent change at various degrees,the woodland had increased by 3 142.25 km2,which mainly derived from farmland and grassland;the farmland had decreased by 3 011.27 km2 because most of farmland changed into woodland and grassland;(2)most areas in Yan′an belonged to the slight or moderate degree of erosion;the total soil erosion rates in 2000 and 2015 were 220 million tons and 138 million tons,respectively;over the 15-year period,all types of erosion intensity had the tendency of change towards the lower degree;(3)the amounts of soil retention in 2000 and 2010 were 772 million tons and 850 million tons,respectively,and the amounts of soil retention tended to increase from northeast to southwest.Woodland and grassland had the best abilities to conserve soil,which indicated that the advancement of GFGP was the important way to increase the function of regional soil conservation.更多还原