2003年在重庆铁山坪森林土壤上一次性投加石灰石和菱镁矿,研究它们对酸化土壤的修复效果.对土壤和土壤溶液连续5 a化学变化的观测结果表明,投加碱性修复剂能提高土壤和土壤溶液pH值,增加土壤盐基饱和度和可交换盐基含量,从而有效地缓减土壤酸化.修复剂粒径是影响起效快慢的重要因素,由于投加石灰石的粒径远细于菱镁矿,所以石灰石样地前2a修复效果相对较好,但5 a后总效果相当,Ca和Mg元素的淋失总量分别为1.00 mole.m-2和0.91 mole.m-2,占原修复剂中相应元素的19%和17%.投加修复剂中的Ca或Mg在5 a后仅有约20%以可交换态存留在土壤中,需要再次投加修复剂以保持修复的效果.但是,单一修复剂的投加有可能加剧其他营养元素的缺乏,因此应开发复合修复剂来改善酸化土壤.
In 2003,filed experiments of surface application of limestone and magnesite on remediation of a typical acidified forest soil were started at Tieshanping,Chongqing in southwest of China.The changes of soil and soil water chemistry in different layers within 5 years after application of limestone and magnesite indicated that the remediation agents leaded to the recovery of acidified soil by significant increase of pH value both in soil and soil water and base saturation in soil.Since the limestone powder applied was much finer and thus more soluble than the magenesite powder,Ca in limestone plots was more mobile than Mg in magnesite ones in the first two years.However,the overall amounts of leaching out of the five years were nearly the same,with 19% of the initial limestone Ca and 17% of the initial magnesite Mg.As only 20% of Ca originating from limestone and Mg originating from magnesite were retained in the soil as exchange cations,more agents should be applied to maintain the remediation effect.Composite agent should be developed while the application of single element agents could probably reduce other nutrient elements content in soil.