模拟酸雨对不同土层酸度和K+淋失规律的影响

在江西表土施用KCl肥料后,用室内模拟酸雨的土柱实验,研究酸雨对不同土层酸度及K⁺淋失的影响.其结果表明,不同土层淋出液pH值的变化先下降后上升,但起始pH值存在明显差异,pH2.5酸雨在A层和AB层淋溶的中后期又下降;淋出液电导变化有一个峰值,其出现在淋溶的起始阶段,表明土壤中养分迅速向下迁移.K+的淋失与降雨的酸度有关,pH2.5酸雨会加速K⁺在土体内向下迁移,在A层土壤中K⁺的释放可分为2个阶段:快速释放过程和中速释放过程;至于pH4.5酸雨淋溶下,K⁺淋失分为快速释放过程和慢速释放过程.

The Influence of Simulated Acid Rain on Acidity and K+ Leaching Regulation of Different Soil Layers

The influence of simulated acid rain on acidity and K⁺ release of different soil layers of red soil from Jiangxi was investigated in the lab when surface soil was mixed with KCl. The results indicated that pH of leaching solution first decreased, then increased in the different soil layers , but pH at the beginning moment of leaching existed prominent differences and pH of leachate of pH2.5 acid rain in A and AB layers again decreased during subsequent stage. There was a peak value of EC of leachate appearing at the beginning stage, it showed that nutrient ions in soil rapidly moved downwards into lower depth of profile. K⁺ concentration of effluent solution was related to acidity of acid rain and the pH2.5 value of acid rain accelerated K⁺ transportation downwards along profile. K⁺ release of A soil layer was divided into two moments which one was the rapid rate of K⁺ release process at the moment of beginning and then into the middle rate of release process. As to pH 4.5 value of acid rain, it also existed rapid and slow rate processes.