外源镧对红壤、水稻土肥力参数的影响

Effects of Lanthanum on Fertility Parameters of Red Soil and Paddy Soil

采用土柱模拟研究了La对红壤、水稻土阳离子交换量、溶液组成、交换性酸等肥力参数的影响。随着外源La浓度的增加 ,积累在红壤、水稻土中的La呈交换态的比例增加 ,红壤比水稻土含有更多的水溶性La和交换态La ,且当La浓度大于 60 0mg·kg- 1 时 ,呈交换态比例基本保持不变。当La浓度小于 12 0 0mg·kg- 1 时 ,对红壤阳离子交换量没有显著影响 ,但La浓度达 12 0 0mg·kg- 1 时 ,对水稻土阳离子交换量产生极显著影响。La增加土壤酸度 ,并主要为交换性Al。La导致土壤胶体表面交换性Ca ,Mg减少 ,土壤溶液中Ca ,Mg增加 ,但当La浓度小于 15 0mg·kg- 1 时 ,对红壤、水稻土阳离子交换量 ,交换性Ca ,Mg和交换性H 。

The effects of exogenous La on the fertility parameters such as cation exchange capacity (CEC), exchangeable basic cations and exchangeable acidity in red soil and paddy soil were studied with soil column simulation. Results show that with the increase of added La, the proportion of exchangeable La in the soils increases and there is more exchangeable La in red soil than that in paddy soil. When the concentration of La is more than 600 mg·kg -1 , the proportion of exchangeable La almost remains constant. When the concentration of La is less than 1200 mg·kg -1 , there is no significant effect on CEC of red soil, but when the concentration of La is more than 1200 mg·kg -1 , there is significant effect on CEC of paddy soil. The application of La results in the increase of exchangeable aluminum, solution Ca, Mg and the decrease of exchangeable Ca, Mg. But when the concentration is less than 150 mg·kg -1 , there is no significant influence on CEC, exchangeable Ca, Mg and exchangeable acidity.