微地形作用下紫色母岩发育土壤的酸化特征  

Effect of Microtopography on the Acidification Characteristics of Soils Developed from Purple Parent Rock

作　　者：谭孟溪 刘莉[1] 王朋顺 程永毅[1] 谢德体[1] 李忠意[1] TAN Mengxi;LIU Li;WANG Pengshun;CHENG Yongyi;XIE Deti;LI Zhongyi(College of Resources and Environment,Southwest University,Chongqing 400716,China)

机构地区：[1]西南大学资源环境学院,重庆400716

出　　处：《土壤学报》2018年第6期1441-1449,共9页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41701256);重庆市博士后项目资助(Xm2016076);西南大学本科生创新基金项目(20172402010)资助~~

摘　　要：为揭示丘陵地区微地形作用下紫色母岩及其不同地形部位发育土壤的酸化特征,在西南丘陵地区采集土壤样品并分析其基本理化性质。结果表明:西南丘陵地区的紫色土已经出现了一定程度的酸化,土壤酸化后使交换性酸含量增加,交换性盐基离子总量和盐基饱和度降低。从丘陵地区的坡顶至坡底,紫色土的发育程度逐渐增加,土壤中维持土壤pH在碱性范围内的碳酸盐遭受到的淋溶作用依次增强。因此,从坡顶至坡底,紫色土的酸化范围逐渐增大。由于酸化后的紫色土pH开始受阳离子交换反应所控制,而在微地形的作用下,受盐基离子遭受淋溶过程和复盐基过程的相对强弱不同的影响,从坡顶至坡底,紫色土的总体酸化程度并未增加。可见,对西南丘陵地区的紫色土的开发利用需考虑到其较为独特的酸化特征。【Objective】 Purple soil is extensively distributed in Southwest China. To study acidification characteristics of the purple soil and its parent purple rock in the hilly areas of that region as affected by micro-topography, this study was launched. 【Method】In this study samples of two kinds of purple rocks and four types of purple soils were collected from the hilly area of Southwestern China for analysis of physicochemical properties in the lab. Samples of the two kinds of purple rocks, mudstone and sandstone, were collected at the top of hills and of the four types of purple soils, stony sub-soil, half sand half mud, bigeye mud and purple yellow mud, distributed in sequence along hill slopes from the top to the bottom, were done, respectively, too, 14 samples each.【Result】 Acidification, to a varying extent, was found in the purple soils of that region. Consequently, in these soils the content of exchangeable acidity increased, and the content of total exchangeable base cation and the base saturation decreased. Purple soil development gradually increased in degree along hill slopes from the top to the bottom. The carbonate in the soils that helped keep soil pH in the range of 8 to 12 was subjected to leaching and the impact increased too along the slope from the top to the bottom. As a result, soil acidification was gradually extending in range along the slope. In terms of acidification degree, the four soils followed an order of purple yellow mud > bigeye mud > half sand half mud > tony sub-soil. In acidified purple soils, pH was controlled by cation exchange reaction, and affected by the degree of base cation(K+, Na+, Ca2+ and Mg2+) subjection to leaching and recovery, which varied with micro-topography. The stony sub-soils on the top of hills were exposed to leaching of base cations only, while the bigeye muds and half sand half muds on the mid slope were subjected to supplementation of base cations leached from the stony sub-soils on the top of the slope, besides leaching loss of base cations. Th

关 键 词：丘陵地区 紫色土 酸化特征 

分 类 号：S153.4[农业科学—土壤学]