基于主成分分析的土壤盐碱化特征研究

Research on the Soil Salinization and Alkalization Characteristics Based on Principal Component Analysis

为探究河套灌区暗管排水条件下葵花生育期内农田土壤盐碱化的主导特征因子,本文基于2020年田间试验数据,利用相关性分析和主成分分析等方法对盐分总量与组成进行分析。结果表明:研究区葵花生育期内,0~1 m剖面土壤盐分组成类型以钠盐为主,经历了从生育初期的苏打型到生育末期的硫酸盐的转变;生育期始末各层土壤中,阴离子从以HCO_(3)^(-)为主转变为以SO_(4)^(2-)为主,阳离子始终以K^(+)+Na^(+)为主;随深度增加,土壤全盐量与可溶性盐离子的相关性发生改变,相关性最强的阴离子为SO_(4)^(2-),阳离子为K^(+)+Na^(+);通过主成分分析,揭示了土壤的盐化和碱化特征因子,得出HCO_(3)^(-)可代表土壤碱化特征,SO_(4)^(2-)、Cl^(-)、K^(+)+Na^(+)可代表土壤盐分组成及土壤盐化趋势,并进一步计算了生育期内各层土壤受盐化和碱化的影响程度。研究结果可为当地暗管排水区域合理布设和改良土壤盐碱化提供理论依据。

In order to explore the dominant characteristic factors of farmland soil salinization during the growth period of sunflower under the condition of concealed pipe drainage in Hetao Irrigation District(HID).Based on the field test data in 2020,the total amount and composition of salt are analyzed by Correlation Analysis and Principal Component Analysis(PCA).The results show that during the growth period of the sunflower in the study area,the soil salt composition type of 0~1 m profile is mainly sodium salt,which experiences the transformation from soda type in the early growth stage to sulfate type in the late growth stage.In each layer of soil at the beginning and end of growth period,anions changes from HCO3-to SO42-,and cations are always dominated by K++Na+.With the increase in depth,the correlation between total salt content and soluble salt ions changes.The anion with the strongest correlation is SO42-,and the cation is K++Na+.Through a principal component analysis,the characteristic factors of soil salinization and alkalization are revealed.It is concluded that HCO3-can represent soil alkalization characteristics,SO42-,Cl-,K++Na+can represent soil salt composition and soil salinization trend,and the influence degree of salinization and alkalization on each layer of soil during the growth period is further calculated.The results can provide a theoretical basis for the rational layout of local underground drainage areas and the improvement of soil salinization.