第四纪红粘土发育的红壤在施用石灰和石膏后元素的淋溶特征

CHARACTERISTICS OF ELEMENT LEACHING OF RED SOIL DERIVED FROM QUATERNARY RED CLAY SUPPLIED WITH LIME AND GYPSUM

本文利用模拟土柱试验研究了施用石灰和石膏对第四纪红粘土发育的红壤中元素淋溶过程的影响。结果表明，施用石灰后１０ｃｍ土层中除Ｃａ２＋以外的阳离子元素的淋失量减少，而ＳＯ2-4；一和ＨＣＯ-３的淋失量增加；施用石膏后１０ｃｍ土层中所有阳离子元素、特别是Ａｌ３＋的淋失量增加。红壤中Ｃａ２＋的淋失以自由态为主，施用石膏后与ＳＯ２－４结合的比例增加。不同处理中 ３０ｃｍ土层处铝的淋失以自由态为主； １０ｃｍ土层处铝的淋失在石灰处理中以羟基铝为主，在石膏处理中初期与ＳＯ２－４结合的比例增加，后期主要以自由态淋失。除了施用石灰的表层红壤溶液中羟基铝比例增加外，在所有的亚表层红壤溶液中以及施用石膏的表层红壤溶液中与ＳＯ２－４结合的铝比例增加。

Summary The affect of applying lime and gypsum on element leashing in red soil derived from Quaternary red clay was studied with soil columns repacked in laboratory. results showed that lime application decreased the leaching from the short columns (0-10cm layer) of cations exclude Ca2+, but increased the leaching of SO^2-_4 and HCO-3. Supplying gypsum increased the leaching. from topsoil column of all cations, especially of Al3+, but has no effect on the leashing of HCO^-_3. Ca2+ leashed mainly in the form of free ion, and the Percentage of SO2-_4 bound Ca2+ rose when adding gypsum. For the leaching of A13+ from the long colunm (0- 30cm layer), it was mainly in the form of free ion. For the leaching of A13+ from the topsoil column, it was mainly in the form of OH- bound A13+ in lime treared soil; however, the main form was SP2-_4 bound Al in the early stage and free ion in the later stage in gypsum treated soil. Besides that the Percentage of OH- bound A13+ enhanced in the topsoil solution in all lime-addition soils, that of So:- bound A13+ increased in all subsoil solution and in topsoil solution in gypsum treated soils.