内蒙古河套平原耕地盐碱化时空演变及其对产能的影响

以内蒙古自治区巴彦淖尔市河套平原为研究区,利用RS和GIS技术在野外样本采集的基础上,以第一次地理国情普查数据和LandsatTM/OLI、GF-1卫星影像为数据源,通过计算盐碱度与波段的相关性构建出反演模型,以专家决策树进行分类,对2006~2014年耕地盐碱化进行动态监测,并分析了不同盐碱化程度农田植被净初级生产力（NPP）时空变化特征。结论表明：2006~2014年研究区域非盐碱耕地和轻度盐碱耕地面积呈现持续减少的趋势,减少幅度为6.23%,占耕地总面积的3.55%,NPP先增后降,减少了2.06%;中度盐碱耕地面积呈先降后增的趋势,净增加幅度为22.40%,占耕地总面积的5.10%,NPP先不变后增加,增加了6.73%;而重度盐碱耕地面积呈现先增后降的趋势,净减少7.68%,占耕地总面积的1.55%,NPP则持续增加,增加了3.81%。总体上看,9 a间虽然因为自然、人为因素的影响,中度盐碱耕地面积增长,但可利用土地面积和有效耕地面积不断增加,且改良区域的NPP处于持续增长的趋势,在一定程度上说明盐碱地治理取得了成效。

Spatio-temporal Evolution of Saline-alkali Cultivated Land and Its Impact on Productivity in Hetao Plain of Inner Mongolia

This study takes Hetao Plain of Inner Mongolia as the research area, based on the RS and GIS technical support and the field sample collection, and uses the China first national geoinformation survey data as the data source, constructs the inversion model through calculating the correlation between the salinity degree and the band, classifies it with expert decision tree, and carries out dynamic monitoring of cultivated land salinization-alkalization in 2006-2014, and analyzes the spatio-temporal characteristics of NPP in different salinization-alkalization degree of cultivated land. The results shows that: Between 2006-2014, the non-saline-alkali cultivated land and the light-saline-alkali cultivated land in the study area showed a decreasing trend, with a reduction of 6.23%, that accounts for 3.55% of the total area of cultivated land. During this period, NPP increases first and then decreases, with a reduction of 2.06%. The medium-saline-alkali cultivated land showed a trend of first decline and then increase, with a net increase of 22.40%, that accounts for 5.10% of the total area of cultivated land. During this period, NPP changed none first and then increased, with a increase of 6.73%. The severe-saline-alkali cultivated land showed a trend of increase first and then decline, with a net decline of 7.68%, that accounts for 1.55% of the total area of cultivated land. During this period, NPP continued to increase, with a increase of 3.81%. In general, although the area of medium-saline-alkali cultivated land increased in nine years because of natural and artificial factors, the available land area and effective cultivated land increased continuously, and the NPP in the improved area shows a trend of continuous growth. The results shows that the control of saline-alkali land has achieved success to a certain extent.