面向敦煌市绿洲土壤质量评价的最小数据集构建研究

Construction of Minimum Data Set for Soil Quality Assessment in the Dunhuang Oasis

地处极端干旱区的敦煌市绿洲在气候条件干旱和人类活动加剧的双重压迫下,土壤资源可持续发展面临着严峻的挑战。本研究基于实地调查数据、MODIS-NDVI和DEM数据,在综合分析土壤理化性质的基础上,选取了14项理化指标,利用最小数据集(MDS)方法,从坡向、植被覆盖度和高程3个方面对研究区的土壤质量进行了评价。研究结果表明:不同坡度条件下,土壤质量为阳坡高于阴坡,而阳坡与半阳坡间,阴坡与半阴坡间差异不大;植被覆盖度对土壤质量影响显著,即土壤质量随着植被覆盖度增高而变好;高程对土壤质量的影响具有两面性,随着海拔升高,土壤盐分降低的同时养分含量也在减少;而干旱气候导致土壤盐分偏高,含水量、有效氮和有机质含量显著偏低。此外,研究中基于MDS的方法,引入Norm值以避免仅用因子载荷作为唯一选择标准而导致的部分因子信息被忽略的缺点,在对MDS的可靠性进行验证显示,相关系数检验说明该方法具有很好的可行性。

Under the dual stresses of drought conditions and human activities, the sustainable development of soil resources in Dunhuang City is facing severe challenges. In this study, the data of field survey, MODIS NDVI and DEM, 14 soil physical and chemical indices were selected in the study area, and soil quality was evaluated according to slope, vegetation coverage and elevation using the method of minimum data set （MDS）. The results showed that soil quality at sunny slope was higher than that at shady slope, but there was no significant difference between sunny slope and semi-sunny slope, also between shady slope and semi-shady slope. Vegetation coverage had significant effects on soil quality. Soil salinity was decreased and the nutrient content was reduced with the increase of altitude. Arid climate leaded to the increase of salt content and the decrease of water content, available nitrogen and organic matter content in soil. In addition, the MDS method introduced the Norm value to avoid the missing of partial factor information when using the factor load as the only selection criterion. Finally, the reliability of MDS was tested and the results showed that the correlation coefficient was high, which indicates that the method was feasible.