Study on Relationship Between pH Value of Protected Field Soil and Its Salinity Content and Composition under Leach Condition

The protected field soil,of which the acidification is serious in Shenyang region,is taken as studying object in this paper.Through the experimental method of leach,the pH value of soil,total salt content and salt ion content which is leached are measured,and the relation among ph value,composition and content of ion is studied.The results are list as follows.Firstly,there is a significant negative correlation between soil pH value and soil salinity content,the soil pH value becomes higher with the decrease of the soil salinity content,but the influence is bigger in later period than pre-period.Secondly,the soil pH value has a relationship with the composition of cation and anion of soil.Among these ions,K+ and other four anions have a curve negative correlation with the soil pH value,while the other three cations have a straight line positive correlation with the soil pH value,both the two correlations achieve the significant level.Thirdly,with the increase of leaching times,the proportion of NO-3 and SO2-4 in total salty content decreases,but the soil pH value increases,at the same time the proportion of Ca2+ and Na+ in total salty content increases,which is also an important factor for the increase of soil pH value.