景电灌区次生盐渍化土地枸杞林的土壤特征研究

摘要

为评价种植枸杞对改良次生盐渍化土壤的效果，实现次生盐渍化土地资源的持续利用，对次生盐渍化土地不同利用方式的弃耕地、不同种植年限枸杞地和小麦地的土壤理化性质进行了调查研究。结果表明，与弃耕地相比，枸杞地土壤有机质、全氮、碱解氮含量显著增加；水溶性盐离子除 HCO3－显著增加、Ca2＋降低不明显外，K＋、Na＋、Mg2＋、Cl－、SO42－、全盐量、电导率均显著降低，离子组成中 Na＋降幅最大，达70．1％～82．9％，全盐量降低70．9％～82．8％；砂砾含量降低、粉粒和粘粒含量升高，CaCO3含量升高，pH 值降低，容重先降低后升高，孔隙度先升高后降低。枸杞地 Na＋和全盐量比小麦地分别高118．1％～282．3％和84．0％～211．5％，其他土壤理化指标和小麦地没有差异。这些说明种植枸杞改善了次生盐渍化土壤质量，除占盐分主导地位的 Na＋含量明显较高外，其他土壤性状恢复至与盐渍化程度低的传统农耕地相当。种植枸杞的前4年间土壤理化性质发生了迅速变化，之后变化速度很缓慢。土地利用方式的变化对次生盐渍化土壤性状具有重要影响。%This study evaluates the effect of planting medlar on the sustainable use of secondary salinized land. The physical and chemical properties of secondary salinized soil were investigated under different land use pat-terns,including an abandoned field (AF),medlar fields with different planting years (MF)and a wheat field (WF).Compared to AF,the MF soils showed significant increases in organic matter,total nitrogen,available nitrogen,and HCO3 - ,while total salt content and electrical conductivity significantly decreased.The most significant decrease was in Na+ (70.1%-82.9%).Results also showed that in MF soils the sand content de-creased and silt and clay content increased.CaCO3 content increased and pH value decreased.However,bulk density firstly decreased and then increased over time,while porosity showed an opposite trend when compared with AF.K+ and total salt content were higher in MF than in WF by 118.1%-282.3% and 84.0%-211.5%respectively.Other soil physical and chemical properties showed no significant differences between MF and WF.The results show that secondary salinized soil quality is improved by planting medlar.Although Na+ con-tent was significantly higher,other soil characteristics were relatively low compared to salinization of tradition-al cropland.The improvement of soil characteristics was rapid during the first 4 years of medlar planting and then slowed considerably.The study thus shows that changes in land use patterns greatly influence the soil characteristics of secondary salinized land.