Abstract:

Soil salinization severely restricted the development of agricultural economy in Hetao irrigation district of Inner Mongolia. Traditional point measurement methods couldn’t supply adequate precision for salinization distribution of large area soil. Remote sensing was applied for solving the problem, which could get the distribution and variation of saline land quickly. But common radar remote sensing had several limitations such as visible light and infrared remote sensing, so radar remote sensing with the characteristics of all-weather and strong penetrability become the focus of research. Response analysis of soil salinization in melting period was carried out in a study area, located in WuYuan county of Hetao irrigation district, combining with the radar remote sensing data from Radarsat-2 four polarization. The study shows that polarization combination of (VH²+HH²)/(VH²-HH²) has strong responsiveness and separability for different saline soils. We establish a regression model(S=0.552 3X-0.645 9) whose parameter is polarization combination. The model has good correlation with determination coefficient R² of 0.768 1. Classification of different saline soils is analyzed with ten soil sampling points. The results show that the relative error is less than 10% for most of the soil sampling points, and the model’s accuracy is superior to that of the traditional classification method.

Key words: radar remote sensing, soil salt, polarization combination, Hetao irrigation district, precision analysis