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.