Analysis On Characteristics And Genesis Of Soil Acidification And Secondary Salinization In Agriculture(Vegetables) In Tianjin

Tianjin facilities agriculture rapid development of 20 years,a large number of facilities to be built agriculture.Wuqing District facilities soil belongs to the fluvo-aquic soil,and Ninghe District facilities soil belongs to salinized fluvo-aquic soil.In this paper,the soil pH value and organic acid and pH value,EC,salt content and soil bulk density,water content,porosity,average particle size,organic matter,hydrolyzable nitrogen were effective in different soils of Ninghe and Wuqing districts.Phosphorus,available potassium,salt and so on.The characteristics of soil acidification and secondary salinization in Ninghe and Wuqing were analyzed comprehensively and in depth.The effects of different salt species and concentration on soil acidification and secondary salinization were studied and analyzed by adding different kinds of salt ions to different soils in Wuqing district.Get the following conclusions:?1?Analysis of soil physical and chemical properties of facilities in Ninghe and Wuqing districts,the physical properties of soil in Ninghe area have improved compared with that of exposed soil,and the soil physical properties of Wuqing area have been reduced.The soil nutrient level in Ninghe District showed 18 years>5 years>open field,and decreased with the increase of planting depth.However,the hydrolyzed nitrogen showed 5 years>18 years>open field,and decreased with the increase of planting depth.The soil organic matter and hydrolyzable nitrogen in Wuqing area showed an increase with the extension of planting period,and decreased with the increase of planting depth.The available phosphorus and available potassium decreased with the extension of planting period,Increase and decrease.The contents of NO₃^-and SO₄2-in the soil ion composition of the facilities in Ninghe area were higher than those in the field.The contents ofK-,Ca²⁺?Mg²⁺ and Cl-were higher than those in the open field.The contents of yin and chen?except K⁺?were 5 years>18 years>open field,decreased with the increase of planting depth,while K⁺ content increased with the increase of planting age,and decreased with the depth of planting.The contents of Na⁺?NO₃^-and SO₄2-in the soil ion composition of Wuqing area were higher,and the contents of K⁺+?Ca²⁺?Mg²⁺ and Cl-were improved.The anions and cations show a decrease with the increase of planting time,K⁺?Ca²⁺?Mg²⁺?Cl-?Na⁺.HCO₃-and SO₄2-7 ions decreased with the increase of planting depth,and N03-increased with the increase of planting depth.?2?The trend of soil acidification in facilities of Ninghe and Wuqing in Tianjin is different.The change of soil acidification in Ninghe area was characterized by an increase of 5 years and 18 years.With the increase of planting depth,Wuqing area showed decreased with the extension of planting period,and increased with the increase of planting depth The The content of organic acids in the Ninghe area decreased with the increase of soil depth,but the content of organic acids in Wuqing area decreased with the increase of age,and decreased with the increase of soil depth.The correlation analysis showed that organic acid was one of the causes of soil acidification.Based on the correlation and partial correlation analysis of soil pH and physicochemical properties,it is concluded that the positive correlation of soil acidification in Ninghe area is water content?hydrolyzable nitrogen and N03^,and NO₃^-is obtained by path analysis.The most significant contributors to soil acidification.The significant factors related to soil acidification in Wuqing area were available phosphorus and available potassium,and NO₃^-was the most significant factor contributing to soil acidification.?3?The trend of soil secondary salinization in Ninghe and Wuqing areas of Tianjin is different.The EC value and salt content of soil in Ninghe area showed 5 years>18 years>open field,decreased with the increase of planting depth,and the soil EC value and salt content of Wuqing area decreased with the increase of planting time.Depth increases and decreases.Based on the correlation and partial correlation analysis of EC and salinity and physicochemical properties,the soil secondary salinization and bulk density,porosity,average particle size,hydrolyzable nitrogen,available potassium and salt ion The results showed that the physical and chemical properties of soil were increased by path analysis,and the secondary salinization of soil was increased.The soil secondary salinization was related to the salt ion in Wuqing area,and the physical and chemical properties were obtained by path analysis Will increase the degree of soil secondary salinization pollution.?4?The correlation between soil pH and EC and salt content in Ninghe and Wuqing facilities showed that soil acidification and secondary salinization were the same,and the two factors were the same.In the Ninghe District,the indexes are divided into three categories according to the cluster analysis.The I type mainly reflects the lower content of soil and the basic physical and chemical properties,which is the secondary index of soil acidification and secondary salinization.Which mainly reflects the high index of non-soil background value,which is the main indicator of soil acidification and secondary salinization.The third category mainly reflects the higher content of soil background value,which will not cause soil acidification and Indicators of secondary salinization.The main component 1 is the content of soil in the soil particle size,the main component 2 is the basic physical and chemical properties of the soil,the main component 3 is the soil moisture content and Wuqing District cluster analysis,the index is divided into three categories,I class mainly reflects the soil acidification and secondary salinization have a certain contribution to the index,is caused by soil acidification and secondary salinization of secondary indicators,II mainly reflects the lower soil content,more basic,is not Acidity and secondary salinization caused by soil physical and chemical properties of indicators,III mainly reflects the non-soil background value of the higher indicators,causing soil acidification and secondary salinization of the main indicators.According to the principal component analysis,the main component 1 is a large number of elements and anions and cations in the soil.The main component 2 is the basic physical and chemical properties of the soil.The main component 3 is soil organic matter and water content.?5?The content of Ca²⁺?Mg²⁺ in the soil increased with the addition of different kinds and concentrations of salt ions,and the contents of Ca²⁺?Mg²⁺ and Na⁺ in the soil increased in 12 years. Indicating that the addition of salt will increase the content of cationic Ca²⁺?Mg²⁺ and Na⁺,but will reduce the content of anions.Salt ions will cause the soil to be acidified for 4 years and 12 years.The most significant salt is?NH4?2SO₄.Salts can cause secondary salinization in the soils of the facility for 4 and 12 years,which will significantly increase the salt content of the soil,includling CaCl₂?NH4HCO₃?K2SO₄.The effect of cations on soil pH and salinity was different from that of different anions by cationic analysis of pH and salinity.The influence of anions on the salinity of soil pH was different after analysis of pH and salinity by anions.The results of cluster analysis showed that NO₃^-and SO₄2-were the main indexes of soil acidification and secondary salinization.Ca²⁺?and Mg²⁺ were the main causes of soil acidification and secondary salinity of secondaryindicators.