Distribution And Spatial Variability Characteristics Analysis Of Saline Soil At Settlement No.1 Of Huanghua In Irrigated Areas In Gansu Shule

This research take the soil salinity in the huanghua farm NO.1 in irrigated areas of Gansu Shule as the study content, and it try to discuss the spacial variability characteristics of soil salinity . Soil samples were taken from 3 layers of each of the profiles distributed in a pattern of"S"and contents of the total salts(Ca²⁺,Mg²⁺,K⁺,Na⁺, CO₃^2-,HCO₃^-,Cl^-,SO₄^2-), pH and EC were determined. Through hierarchical cluster analysis Soil salinity profiles. And Discussion profiles of the different types of salt in soil salinity vertical distribution. we use Geostatistics to analyse special variability of soil salinity, pH ,EC base on the data, the Kriging method was applied to estimate the unobserved points and then the precise contour maps were obtained. Bythis way, the spatial variability of soil saltions, pH and EC could be reflected directly.Results showed that: (1) Salt accumulation at the surface soil layer was generally significant except individual,Soil salinity exhibited strong variation in verticall spatial distribution. (2) On the ions and the relevance of EC, the cation-anion with the EC as a significant positive correlation, in which Na⁺ cations and SO₄^2- anion in the main . (3) KarhUnen-Loeve showed the main composition of soil salinity is Na⁺,Mg²⁺,Cl^-,CO₃^2-,SO₄^2-,and CO₃^2-,HCO₃^- is determinative factor of alkalinity. (4) The coefficient variation of pH was weak variation, total salts,Ca²⁺,Mg²⁺,Na⁺,HCO₃^-,SO₄^2-,EC were moderate variation, K⁺,CO₃^2-were strongly variation. Cl^- was moderate variation in middle layer,but in surface layer and bottom layer it was strongly variation. All those responded that the salt ions in the research area were affected by complex factors. (5) The chemical analysis of semivariograms indicated that in surface layer(0-30cm) total salts, Ca²⁺,K⁺,Na⁺,CO₃^2-,SO₄^2-,pH,EC were best described by spherical model; Mg²⁺,HCO₃^- showed the pure nugget effect; and Cl^- fitted exponential model. in middle layer(30-60cm) total salts, Ca²⁺,Mg²⁺,K⁺,Na⁺, CO₃^2-,HCO₃^-,Cl^-,SO₄^2-,pH,EC were best described by spherical mode; in bottom layer(60-100cm) total salts, Ca²⁺,Mg²⁺,Na⁺,Cl^-,SO₄^2-,pH,EC were best described by spherical mode, K⁺ showed the pure nugget effect; CO42- and HCO₃^- fitted exponential model. (6) After we finished the Kriging map of salt in three soil layer respectively, we found that most salt ion had the better spacial variability characteristics and better regularity.The spatial distribution of salt ion was same as soil salinity. Comparing with the Kriging maps of saltion we estimated the soil have inverted salinity profiles by analyzing the areas of every type of salinity soil. From the 0-30cm to 60-100cm soil layer, the proportions about the areas of non-salt type soil and light-salt type soil.From this research we would get lots of scientific help about soil salinity treatment , improvement , agriculture planning , adjusting, and irrigation and drainage engineering planning in the future.