镁、锰、活性炭和石灰对土壤pH及镉有效性的影响

Effect of Magnesium,Manganese,Activated Carbon and Lime on Soil pH and Available Cadmium

采用土壤培养方法研究单独添加不同量的硫酸镁、硫酸锰、活性炭和石灰性物质及其配合施用对土壤pH和镉有效性的影响。结果表明:镁、锰、活性炭和石灰性物质对土壤pH和Cd有效性的影响存在显著差异。添加石灰能显著提高土壤pH,pH增加幅度与石灰用量呈正相关;而添加镁、锰和活性炭都能降低或显著降低土壤pH,降低程度与用量呈负相关。这几种物质,无论单独施用还是配合施用都能降低或显著降低土壤有效镉的浓度,单独施用的效果总体上为石灰>硫酸锰>硫酸镁>活性炭,而配合施用的效果则为石灰+硫酸锰+硫酸镁>硫酸锰+硫酸镁>石灰+硫酸锰>石灰+硫酸锰+硫酸镁>石灰+活性炭。氢氧化镁对降低土壤Cd有效性的效果优于等量氢氧化钙(石灰)。

An incubation experiment was conducted to investigate soil pH and available cadmium（Cd） as affected by addition of magnesium sulfate（Mg）,manganese sulfate（Mn）,activated carbon（AC） and lime materials（lime） when applied alone or in combinations.Results showed that Mg,Mn,AC and lime significantly affected soil pH and concentrations of available Cd.Soil pH was remarkably enhanced with addition of lime and positively correlated to its application rates,while soil pH was significantly reduced with addition of Mg,Mn or AC,and negatively correlated to its application rates.No matter these materials were added alone or in combination,concentrations of soil available Cd were reduced or significantly reduced.The effects of these materials on depressing soil available Cd concentrations followed an order of lime Mn 〉Mg 〉AC when applied alone, and an order of lime＋Mn＋Mg 〉Mn＋Mg 〉lime＋Mn 〉lime＋Mg＋Mn 〉lime＋AC when used in combinations. The effect of Mg（OH）2 on reducing soil available Cd was superior to Ca（OH）2.