西北地区新一轮退耕还林还草规模分析

西北地区干旱少雨、水土流失严重、生态环境脆弱,退耕还林还草工程是西北地区生态环境建设的重大举措,也是全国生态环境建设的一项宏伟生态工程。通过对退耕还林还草工程实施现状、生态效应及存在问题的整合分析,探讨了西北地区新一轮退耕还林还草工程的实施规模。结果表明:(1)西北地区1999—2011年退耕还林还草面积累积751.99万hm~2,占全国同期退耕还林还草面积的36.14%;陕西、甘肃、青海、宁夏、新疆、山西和内蒙中西部地区退耕还林还草的实施面积分别占西北地区同期退耕还林还草面积的27.89%,21.29%,4.62%,9.80%,10.80%,13.57%和12.03%。(2)自退耕还林工程实施以来,2002—2012年西北地区农民纯收入逐年增加,且各省(区)增加趋势一致。(3)西北地区植被覆盖在提高,植被NDVI整体呈上升趋势,但存在明显的空间差异,空间分布是从东南向西北逐渐递减,而陕北地区是黄土高原近10年植被恢复最快的区域。(4)2003—2014年黄河流域径流量和侵蚀量均低于1950—1995多年平均值,且年际间波动较大。(5)25°以上的坡耕地可退耕180.1万hm~2,占现有耕地的6.0%,15°~25°的坡耕地退耕面积可达296.5万hm2,占现有耕地面积的9.9%,并厘清了各省(区)的退耕规模,最后针对新一轮退耕政策的顺利实施,提出了4点建议。

Analysis on the Scale of A New Period of Returning Farmland to Forestland and Grassland in Northwest China

Drought,serious soil erosion and fragile ecological environment are the key issues in the Northwest China.The project of returning farmland to forestland and grassland is the important measure for the construction of ecological environment in the northwest region,and also a magnificent ecological project of the national ecological environment construction.Based on the integrated analysis of the present situation,the ecological effect and the existing problems in the implementation of the project of returning farmland to forestland and grassland,the scale of the project of returning farmland to forestland and grassland in the Northwest China was discussed.The results were as follows.(1) The area of returning farmland to forestland and grassland was 7.519 9 million hm2 during the period from 1999 to 2011 in the Northwest China,accounted for 36.14％ of the returned national area during the same period.The areas of returning farmland to forestland and grassland of the Shaanxi,Gansu,Qinghai,Ningxia,Xinjiang,Shanxi and Inner Mongolia Midwest,accounted for 27.89％,21.29％,4.62％,9.80％,10.80％,13.57％ and 12.03％ of total returned area in the northwest region in the same period,respectively.(2) Since the implementation of the project,the net incomes of farmers in the northwest area increased year by year from 2002 to 2012,and the increasing trend of the provinces or regions was the same.(3) In northwest region,the vegetation cover was improving,and NDVI was in the upward trend on the whole,but there are obvious differences in the space,spatial distribution was gradually decreasing from southeast to northwest,and the northern Shaanxi is a region with the fastest speed of vegetation recovery during recent 10 years in the Loess Plateau.(4) During 2003-2014,the runoff and erosion in the Yellow River basin were lower than those during 1950 1995,and the annual fluctuations were large.(5) the area of slope farmland with more than 25 degrees was 1.801 million hm2,accounting for 6.0％ of the existing cultivated land,area of slope farmland with 15～25 degrees was up to 2.965 × 106 hm2,accounting for 9.9％ of the existing land area,and the farmland scales of the provinces or districts were clarified,and finally,four suggestions were put forward to aim at the smooth implementation of farmland policy of a new period.