【摘要】 通过野外定位观测和室内分析,探讨了松嫩平原盐渍化区土壤的微域特征.结果表明:研究区由高平地、微坡地、洼地边缘和洼地4种微地貌单元组成.洼地发育均腐土,洼地边缘、微坡地和高平地发育碱积盐成土.高平地土壤的碱土碱化层出现在15～30cm,碱化度(ESP)60%.微坡地土壤表层的ESP最大可达75%.洼地边缘的ESP分布在10～30cm土层,最大为30%～40%.洼地的土壤几乎没有碱化层.研究区不同微地貌部位发育的土壤水分特征曲线存在明显差异.微坡地土壤饱和含水率最大仅为25%,而洼地土壤0～10cm饱和含水率高达45%.不同微地貌单元的冻融过程存在明显的差异.微坡地和洼地的最大冻结深度分别为157和136cm.冻结期,洼地土壤表层含水率由冻结前的20%增加到50%.微坡地土壤表层含盐量变化在4个微地貌单元中最明显;冻融前后微坡地土壤表层含盐量增幅达80%.更多还原

【Abstract】 The study by the methods of in situ observation and laboratory analysis showed that the micro-relief in salinization area of Songnen Plain area was composed of flat land,micro-slope land,depression margin,and depression.Isohumusols distributed in depression,while alkalic halosols distributed in depression margin,micro-slope land,and flat land.The exchangeable sodium percent(ESP)in alkalized layer(15-30 cm)of alkaline soil in flat land was 60%,and the maximal ESP in surface soil layer in micro-slope land could reach to 75%.The alkalized soil layer in depression margin was mainly at the depth of 10-30 cm,where the maximal ESP could reach to 30%-40%.Nearly no alkalized layer was found in the soil profile in depression.The soils developed on the four micro-relief units had obvious differences in their water retention curves.The maximal saturation moisture content in the soils of micro-slope land was only 25%,while that of 0-10 cm soil layer in depression reached to 45%.The freezing-thawing process in different micro-relief units differed markedly,with the maximal frozen depth in micro-slope land and depression being 157 and 136 cm,respectively.The surface soil moisture content in depression increased from 20% before freezing to 50% during freezing period.Among the four micro-relief units,micro-slope land had the most obvious variation of surface soil salt content during freezing-thawing,with the increment after thawing being as high as 80%.更多还原