辽宁省白浆化土壤中白土层的特征及其形成

Characteristics of the Pale Color Horizon in Albic Soils in Liaoning Province and Their Forming Processes

本文以辽宁省浑河在不同历史时期形成的阶地上的黄土状物质发育的土壤为研究对象,通过对剖面形态学特征、基本理化性质和母质均一性判定等研究,探讨了浑河三级阶地白浆化土壤的白土层特征及其形成机制。结果显示:(1)土壤粉粒中的稳定元素钛与锆分析结果表明在三级阶地上的21-003、21-009、07和21-076剖面和二级阶地上的21-001、21-200、03和04剖面的母质均一;(2)由于土体发育程度不同,一级阶地土体中无淀积层;二级阶地土体中有淀积层且无白土层,尚未出现白浆化现象;三级阶地土体中淀积层和白浆化现象明显,出现了白土层,其形成以黏粒的机械淋溶和潴育淋溶为主;三级阶地上土壤比二级阶地和一级阶地发育时间长,但尚未达到漂白层的标准。

Albic bleached soils derived from loess-like materials on different terraces formed under different historicalperiods in the Hunhe River of Liaoning Province were studied. Profile morphological features, basic chemical properties andparental material uniformity were detected and used to ascertain the characteristics and formation mechanism of pale colorhorizons. The stable elements of titanium and zirconium in silts showed that profiles of 21-003, 21-009, 07 and 21-076 in the thirdterrace share the same parental material with profiles of 21-001, 21-200, 03 and 04 in the second terrace. Soils in the first terracehave no illuvial horizon; soils in the second terrace have illuvial horizons without albic bleached phenomenon or pale colorhorizon; soils in the third terrace have obvious illuvial horizons, albic bleached phenomena and pale color horizons. Theformation of pale color horizon is mainly due to stronger eluviation and illuviation under a longer time period with significantdepletions of clays in profiles when compared to soils in the first and second terraces. However, the properties of pale colorhorizon have not reached the standard regulation for an albic horizon.