摘要
[目的]为研究外源镁对强酸性紫色土壤阳离子交换效应。[方法]选择重庆地区强酸性紫色土壤为对象,采用1∶5的土水比,用10 cmol(+)/L MgSO4溶液对土壤进行多次交换处理。[结果]在实验条件下,外源镁能快速取代土壤胶体上吸附的各种盐基离子,但对致酸离子(H+、Al3+)则难以达到快速、完全取代,经5次交换后,盐基饱和度由46.6%上升至72.4%,土壤pH仅上升0.7个单位;Mg2+与Ca2+、Na+的交换分别可以用指数方程y=14.998e-1.484 9x(R2=0.993 8)、二次方程y=0.011 1x2-0.100 5x+0.233(R2=0.986)进行很好地拟合;Mg2+与K+的交换后期明显表现出有部分土壤次生黏土矿物层间固定的K+会被交换出来,导致被交换出的K+总量增加。[结论]在无酸碱中和的条件下,外源镁可以改变土壤胶体盐基离子的构成,但对于改良强酸性土壤并无实际意义,反之,过量的外源镁还可能造成土壤其他盐基离子的损失。
[ Objective ] The research aimed to study the effects of adding exogenous magnesium on the cation of strongly acidic purple. [ Method] Strongly acidic purple soil in Chongqing region was taken as an object. Soil water ratio was 1：5. With 10 cmol （ ＋ ）/L MgSO4 solu- tion for exchanging the soil a few times in a row, the exchangeable solution which was swapped out of base cations and soil pH after exchange were measured. [ Result] Under the experimental conditions, exogenous magnesium could quickly replace variety of base cations adsorbing on soil colloids, but the acid-induced ion （H ＋ , A13＋） was difficult to be replaced rapidly and completely. After five times exchange, the base saturation was increased from 46.6% to 72.4%, but the soil pH only increased 0.7 units. The exchange of Mg2＋ , Ca2＋ and Na＋ could re- spectively be fitted by exponent equation y = 14.998e - 1. 484 9x （ R2 = 0. 993 8 ） and quadratic equation y = 0. 011 lx2 - 0. 100 5x ＋ O. 233 （R2 = 0.986）. In the late of exchangeable time of Mg2 ＋ and K ＋ , it was clearly demonstrated that the fixed K ＋ in some soil secondary inter- layer minerals was swapped out, which resulted in the increase of total content of exchangeable K ~. [ Conclusion] In the absence of acid-base neutralized conditions, exogenous magnesium could change the structure of base cations on the soil colloids. However, it was insignificant for the improvement of strongly acidic soils. On the contrary, excess exogenous magnesium would make other base ion loss in soils.
出处
《安徽农业科学》
CAS
2014年第4期1056-1058,共3页
Journal of Anhui Agricultural Sciences
基金
"十二五"国家水专项(2012 ZX 07104-003)
关键词
强酸性土壤
外源镁
阳离子交换
效应
Acid soil
Exogenous magnesium
Cation exchange
Effect
