Analysis Of Soil Salinity In Arid Area Plain Under Human Activity Stress

Soil salinity and its ion and water content are important indicators to measure the degree of soil salinization.However,the degree of soil salinization in arid areas is increasing with the increase of human stress.In this paper,the soils under different stress levels of human activities in a region of Xinjiang Fukang were studied.The differences in salt content and ion content,spatial distribution differences,salt and water spatial and temporal distribution changes,and CR and FDCR.The soil salinity under different human stress was predicted by the depth,width and area characteristics of the soil,and the soil in the arid area was provided by the knowledge of salinization under different human stress and the improvement of salinized soil.The main conclusions are as follows:?1?The average pH value of the soil is 7.86,which belongs to alkaline soil;and the soil salt is 17.7?g/kg?,which is generally strong salinized soil.With the increase of human activity stress,the degree of soil salinization increased,and the salinization degree was the highest in severe stress areas.Salinization and saline soil accounted for73.3%of all soil samples.The content of CO₃^2-in the eight major ions of human soil was lower,and the contents of Cl^-,SO₄^2-and Na⁺were higher.The Cl^-content of soil in the A,B and C areas were 1.99,3.34 and 6.65?g/kg?,respectively.There was a significant positive correlation between soil salinity and Na⁺and Cl^-content,and the correlation coefficient increased with the increase of human stress.The correlation between salt and Cl-correlation coefficient was the most obvious,and the B and C areas increased by 51%and 77%,respectively,compared with the A area.The correlation coefficient between Na⁺and Cl^-is larger between ions,and increases with the increase of human stress.The clustering results showed that the three main ions of the soil salinity were Cl^-,Na⁺and SO₄^2-under three stress levels,so these three ions were used as the main salt segregants in the study area.?2?The spatial autocorrelation of soil Cl^-under three human activity stresses was higher than that of Na⁺,and SO₄^2-did not have spatial autocorrelation.The comprehensive Moran's I coefficient,Z value and p value out of the stress-free zone Cl-is the highest spatial autocorrelation factor.The Moran's I,Z and p value are 0.27,2.63and 0.002,respectively,and the confidence can pass 99%significance test.The corresponding degree of soil salinity and ion content distribution under different human stress increased with the increase of stress degree.The correspondence between salt and Cl^-,Na⁺and SO₄^2-in severe interference zone was 89%,82%and 75%,respectively..The soil water-salt distribution in spring and autumn with or without human stress was 68%and 51%in the non-stress zone,and the artificial stress zone was 70%and 62%.The general rule of time and space change of soil water and salt is that the water content of the non-stress zone is mainly increased in space,and the increase area accounts for 62%of the total area.The salt content is mainly reduced in space,and the reduction area accounts for 58%.The artificial stress area The salt content increases as the water content decreases,and the area of the decrease/increased ratio is 70%and 66%.?3?As the degree of stress in human activities increases,the spectral reflectance of soil increases.The correlation between soil CR and FDCR and salinity is different in each region.Generally,as human stress increases,the correlation gradually decreases.Compared with FDCR,CR has a higher correlation with salt.The sensitivity bands of soil CR under different human stress levels are mainly concentrated in the visible range,and FDCR is distributed in the visible-near infrared range.The soil CR has different absorption depth,width and area characteristics in the two bands of 400⁶10 nm and610⁸00 nm.The 400⁶10 nm is intensified with human stress,and the absorption characteristic value is increased.The latter has reduced.The absorption area of the three characteristics of absorption depth,width and area can best reflect the soil salt information,followed by the absorption depth and the width.The best model for predicting soil salinity content from all prediction models is six absorption eigenmodels.The R² in the three human active stress zones are 0.82,0.75 and 0.69,respectively,and the RPD is 3.36,3.27 and 2.81,respectively.This model can predict the soil salinity in the stress-free and moderate stress areas,and predict the soil with severe stress.