基于EM38和遥感影像的土壤表观电导率建模研究

Soil conductivity model based on EM38 data and remote sensing image

选取阿克苏地区渭干河-库车河绿洲外围的典型盐渍化区域作为研究对象,应用EM38大地电导率仪测量该地区样点表观电导率,选取四种不同的土壤盐分指数,结合同时期的遥感影像建立基于影像波段的土壤盐分指数回归模型,通过统计软件进行相关分析,发现表观电导率与土壤盐分指数S2即(b1-b3)/(b1+b3)的相关性最高,然后将不同层的土壤表观电导率同S2进行曲线拟合,对不同模型的拟合效果进行对比分析,结果表明:增长模型即复合比级数曲线模型的拟合度最高,通过精度验证,模型不适用于灌区,而荒漠区的各层的预测值与实测值相关分析结果都达到显著性水平,利用该模型可进行荒漠地区表观电导率的反演,因此基于电磁感应技术的土壤表观电导率建模研究可以为快速土壤盐渍化监测提供一种新方法。

Remote-sensing data based salinity indices or band combinations were developed to monitor the occurrence pattern of salt-affected soil.The EM38 is applied to measure the conductivity of the soil.The paper presents an integrated approach to characterize soil salinity using remotely-sensed data and EM38 data.The research took the saline soil of Weigan-Kuqa River Delta Oasis to the Southeast margin of the Tarim Basin in Xinjiang as objects,four salinity indices were selected to establish regression model between SI and soil apparent conductivity.Results indicated that growth model can characterize well the changing trend of electrical conductivity at each soil layer.The prediction error of each profile of electrical conductivity was analyzed.The correlation coefficient between measured point and predictive value via growth model was 0.508 at top soil inside the oasis,and reached a significant level at each profile in the desert.The results demonstrated that growth model was not fit for irrigated soil.Growth model was used to retrieve soil apparent conductivity of the desert.The research provided some scientific basis with soil salinization detection.