Crop Cultivation and the Changing of Soil Salt Contents

Location tests on soil salt movement was carried out by using isolated pool with undisturbed soil.Results showed that during crop cultivation period the mildly salinized or desalted Chao soil with salt content of 0.11-0.28% went on desalination at rate about 0.0125% per year.During the winter wheat season soil salt moved upward and accumulated on top layer of soil,during summer maize season the soil salt moved downwards to deeper layer of soil.Salt movement can be taken as thetransfer of salt ions among soil layers,and the intensity of movement for different salt ion is difference with that of CL^- and Na⁺ being more than SO₄^-2 and Ca⁺²,while CO₃^-2 rarely moves.