宁夏红寺堡扬黄灌区土壤沙化和盐渍化及其相互关系

Soil sandy desertification and salinization and their interrelationships in Yanghuang irrigated area of Hongsipu, Ningxia of Northwest China

采用控制取样和典型取样相结合的方法,对比分析了红寺堡扬黄灌区玉米地和枸杞地、未利用地0～40cm分层土壤质地、盐渍化特征、阳离子交换量(CEC)值及其相关关系.结果表明:控制取样条件下,除未利用地0～10cm土壤含盐量(TS)达1.74g·kg-1外,3种利用方式下0～40cmTS在0.69～1.30g·kg-1之间变化,盐化特征不明显;枸杞地20～40cm土壤钠吸附比(SAR)和土壤碱化度(ESP)分别达到12.18%和14.1%;玉米地0～20cm粘粉粒和(CPS)为13.5%,枸杞地0～40cmCPS达37.3%.控制取样条件下,20～40cm土层玉米地土壤碱化和沙化指标间显著相关;典型取样条件下,上述相关性消失,但CEC与沙化指标及盐渍化指标均显著相关.不同土地利用方式下灌区土壤沙化和盐渍化呈复杂的交互关系,CEC可以作为土壤环境质量变化的综合指示因子.

By the methods of controlled and typical sampling, this paper analyzed the texture, salinization characteristics, cation exchange capacity （CEC）, and their correlations in the 0-40 cm soil profiles of corn land, medlar land, and non-utilized land in Yanghuang irrigated area of Hongsipu, Northwest China. Under controlled sampling, the salt content in the soil profiles was 0.69-1.30 g·kg-1 （except in non-utilized land where the 0-10 cm soil salt content was up to 1.74 g·kg-1）, with no obvious salinization. The sodium adsorption ratio and exchangeable sodium percentage in the 20-40 cm soil layer of medlar land were 12.18 and 14.1%, respectively, and the total content of clay and silt in the 0-40 cm soil profile of medlar land was up to 37.3% whereas that in the 0-20 cm soil layer of corn land was only 13.5%. In the 20-40 cm soil layer of corn land, the indices of sandy desertification and salinization had significant correlations under controlled sampling but no correlations under typical sampling, while the CEC and the sandy desertification and salinization indices had significant correlations under typical sampling. In different land use types in the study area, soil sandy desertification and salinization had complicated interrelationships, and CEC could be used as the indicator for the changes in soil environmental quality.