模拟酸雨对土壤化学及其蔬菜生长的影响

酸雨对陆生生态的影响往往是通过土壤肥力衰退而实现,在此过程中,盐基性元素的淋容和重金属元素的活化是最重要的。经研究发现,在酸雨淋洗的早期,土壤 pH 因盐基阳离子的释放而上升,但在继续淋洗之后,土壤 pH 值下降,土壤交换性盐基总量减少,表明了土壤酸化是不可避免的。从模拟盆栽试验和田间调查都表明,它将导致蔬菜生长不良,甚至死亡,这使得土壤对蔬菜作物的宜种度下降,最明显的是蕃茄不能生长或结果。土壤酸化还将导致土壤中重金属元素(Fe、Mn、Cu、Zn、Pb 和 Al)的活化度增加,研究还表明。酸雨 pH 降至3.0时,中性与酸性紫色土都将在五年内发生酸化,而当酸雨 pH 值为4.0时,则必须十年以上雨量方可使土壤酸化。因此,可以认为,现代酸雨如重庆、贵阳等地方,将对土壤、植物、动物以至人类都是有危害的。

Effect of Simulated Acid Rain on Soil Chemistry and Vegetable Growth

Acid rain always affects the terrestrical ecology in the way of dec- linating soil fertility.In this process,the mobility and leaching of basic elements and heavy metal elements of soil are most important.It was discovered that the soil pH rise following the basic cation released at the earlier step of the acid rain leaching,but the soil pH fall down and ex- changed basic cation decreased after the leaching continously.It was show- ed that the soil acidification is unavoidadle with pH 4.0 of acid rain. Some vegetables studied in pot experiment and field investigation exhi- bited negatively effect on growth,and even wilting,especially on toma- toes,it will cause the decrease in adaptablitity of soil to vegetables. Soil acidification will cause increasing heavy metal(Fe,Mn,Cu,Pb Zn, and Al)mobility in soil as well.The studies showed that when the pH of rain dropped to 3.0 the neutral and acid purple soil could be acidified within 5 years,while the pH of rain is 4.0,then 10 years rainfall might be necessary.Therefore,the author concludes that the present acid rain, such as in Chongqing and Guiyang,is so dangerous which will do harm to earth,plant,animal,and even to human in future.