苏北典型新围垦海涂农田盐碱障碍因子特征分析

摘要

通过对苏北典型新围垦海涂农田(围垦于2005年,种植于2007年)盐碱障碍因子分析发现,农田土壤处于脱盐碱化阶段,其盐分均值为1.78 g/kg,属轻度偏中度盐渍化,但其变幅大,空间变异性强,盐分大值呈斑块状分布于田块中.同时,其pH高,均值达9.83,碱化特征明显.海涂围垦农田土壤盐分与pH的剖面分布均较均匀,垂直变异性弱.离子分析结果显示,海涂围垦农田土壤盐分以NaCl为主,除K+外,土壤可溶性离子按其与盐分和pH的关系大致可以分为两类,一类为Cl-、SO42-、Ca2+、Mg2+、Na+,分别与土壤含盐量呈显著正相关；另一类为CO32-、HCO3-,分别与pH值具有极显著的正相关关系；且同类离子之间互呈显著正相关,而两类离子相互之间呈显著负相关或极弱正相关.K+既与土壤含盐量和pH呈极显著正相关,同时也与除SO42-和Ca2+外的所有离子呈正相关.结合研究区气候特征,在消减新围垦海涂农田土壤盐碱障碍因子的过程中应积极改善土壤的物理性质以增强盐分的淋洗,并重点防止土壤的碱化过程.%Results of study on soil total salt content and soluble ions of a newly reclaimed mudflat farmland reclaimed in 2005 and cultivated in 2007 showed that the farmland soil was in the process of desalting alkalization characterized by a lower salt content and a high pH value.The average soil salt content was 1.78 g/kg,with a strong spatial variability,and the mean value of soil pH was up to 9.83.Both soil total salt content and pH distributed uniformly in soil profiles with lower variability.Based on the relationship between the soluble ions and soil total salt content,pH,soluble ions could be divided into two parts,the first part,including Cl-,SO42-,Ca2+,Mg2+,Na+,especially Cl-and Na+,determined soil salt content,the second part,consisting of CO32-and HCO3-,controlled soil pH value.Both the correlation of ions within the first and second parts both were positive significantly generally,however,the correlation of ions between the two parts were negative significantly or positive weakly.The correlations of K+ and soil salt content,K+ and soil pH value were positive significantly.Also,there was a significant positive correlation between K+ and other ions except for SO42-and Ca2+.Based on the climatic characteristics,it is important to improve mud flat soil physical character to enhance salt leaching and prevent soil alkalization in the elimination process of saline-alkaline barrier factors.