Abstract:

Soil salinization is one of the main problems for agricultural development in Ningxia irrigation district. In order to ascertain the main salt ions causing soil saline-alkali damage, and to provide scientific evidence for improving saline-alkali land, correlations between soil salinity and salt ions of different types of saline-alkali soil in Ningxia irrigation district were studied by the methods of correlation and principle component analysis. The results showed that, there were significant positive correlation between salt content of the saline soil and other salt ions except HCO3-. Whether saline soil or alkali soil, there were extremely significant positive correlation between total soil salt content and SO42-, Cl-, Na+, respectively. There were significant positive correlations among Na+ and Cl-, SO42- with a correlation coefficient greater than 0.80. Soil alkalinity of the alkali soil and pH showed an extremely significantly positive correlation with CO32- content. The principal component analysis results showed that, Na+, SO42- and Cl- contents were Eigen factors of soil salinization condition of the study area, and Cl-, SO42-, Na+ and CO32- contents were Eigen factors of soil alkalization condition of the study area. In order to eliminate soil salinization and basification of the study area, it should focus on eliminating these harmful salt ions contents such as Cl-, SO42-, Na+ and CO32-.