模拟酸雨影响下红壤中硼的释放特征

为了探明酸雨对红壤中硼释放的影响,了解土壤缺硼机制,采用室内模拟酸雨淋溶土柱的方法,研究了酸雨作用下红壤中硼的释放特征.结果表明,酸雨加速了红壤中硼的淋溶损失.酸雨作用下红壤中硼的释放随淋溶量的变化具有初期阶段减小,中期阶段显著增大和后期阶段又减小的阶段性特点.模拟酸雨的pH值越低,硼的释放量越高.酸雨对硼释放的这种促进作用,一般表现为中期阶段的影响要大于初期和后期阶段的影响.淋出液中硼含量的动态变化与pH值的变化成负相关关系.供试土壤不同,硼的释放强度和释放特征存在一定的差异性,硼的释放强度和特点明显受土壤硼的背景值和土壤对酸缓冲能力的影响.

Studies on release of boron from red soils under the influence of simulated acid rain

In order to prove up the influence of acid rain on the release of boron from red soils, and to understand the mechanism of soil being short of boron, an indoor simulated acid rain soil leaching column technique was adopted toinvestigate the release character of boron from red soils under the action of acid rain. Acid rain accelerates the leaching damage of boron from red soils. Under the action of acid rain, there is a stage character of boron release from red soils changing with the leaching amount. At initial stage of leaching the boron release declines, at middle stage increasesobviously and at last stage declines again. The lower the pH values of simulated acid rain, the higher the boron released. Generally, this promotion of acid rain on release of boron manifests that the influence at middle stage is greater than that at both initial stage and last stage. The dynamic change of boron content in leachate is correlative negatively to the change of pH value. The strength and character of boron release are different definitely with different soil sample, which means marked influence of the background value of soil boron and of the buffer capacity of soil on the acid.