摘要
本文研究了红壤与黄棕壤的粘粒矿物组成与土壤的表面电荷特征。红壤的粘粒矿物组成以高岭石、水云母为主,伴有一定量的14埃过渡矿物,少量的蛭石与石英;黄棕壤则以水云母、高岭石、蛭石为主,伴有少量的14埃过渡矿物和石英。测出红壤粘粒的外表面比黄棕壤的大,内表面和总表面比黄棕壤的小。红壤的表面电荷零点pH_0为3.57,黄棕壤的pH_0为3.06;钙离子的吸附使土壤的pH_0移至较低值,硫酸根离子的吸附使土壤pH_0移至较高值。红壤的净电荷零点(ZPNC)为1.55,黄棕壤的ZPNC为1.59。两种土壤的pH_0都大于其ZPNC。根据Uehara和Gillman(1980)表面电荷模式判断,两种土壤的永久电荷都为负电荷。测出的永久负电荷量,黄棕壤为每百克土8.22毫克当量,红壤为每百克土10.10毫克当量,黄棕壤每百克粘粒为17.33毫克当量,红壤每百克粘粒为15.64毫克当量。
Clay mineral composition and surface charge characteristics of red earth and yellow brown earth were studied. Kaolinite and illite are the main clay minerals in red earth together with a certain amount of 14A intergrade mineral and a little vermiculite and quartz. Illite, kaolinite and vermiculite are major clay minerals and there is a little 14A intergrade mineral in yellow brown earth. The external specific surface of red earth clay is larger than that of yellow brown earth, but the internal specific surface and total specific surface of red earth is smaller than that of yellow brown earth. The zero point of charge (pH0 ) for red earth is equal to 3.57 while for yellow brown earth, pH0 is equal to 3.06. Adsorbed calcium ions shift the pH0 to lower values and specifically adsorbed sulfate anions shift the pH0 to higher values. For red earth, the zero point of net charge ( ZPNC ) is equal to 1.55, for yellow brown earth ZPNC is equal to 1.59. The pH0 of the two types of soils are larger than their ZPNC. It was found that a negative permanent charge exists for these two types of soils by using the surface charge model developed by Uehara and Gillman ( 1980) . The negative permanent charge of yellow brown earth equals 8.22meq/100g soil, and of red earth equals 10.10meq/100g soil.
出处
《华中农业大学学报》
CAS
CSCD
北大核心
1989年第1期53-62,共10页
Journal of Huazhong Agricultural University
基金
国家科学基金~~
关键词
红壤
黄棕壤
粘粒矿物
red earth
yellow brown earth
clay mineral composition
surface charge characteristics
Wuhan
