硅藻土对磷在红壤中吸附解吸的影响

Effects of Diatomite on Phosphorus Adsorption and Desorption in Ferrosols

为提高磷肥利用率和研究磷肥增效技术,通过恒温振荡试验研究了硅藻土对水溶性磷肥(磷酸二氢钙)在红壤中有效性的影响。结果表明,在0.31 mg P/g土和1.25 mg P/g土水平下,硅藻土显著地降低了供试土壤对磷酸二氢钙的吸附,增加了水溶性磷、0.01 mol/L CaCl2溶液解吸磷和Olsen P的含量,且三者随硅藻土用量的增加而增加,其主要归因于硅藻土多孔、比表面积大和富含羟基的结构组成。硅藻土与磷酸二氢钙的施用顺序也显著地影响着供试土壤中磷的有效性,硅藻土先于磷酸二氢钙加入供试土壤处理的水溶性磷和0.01 mol/L CaCl2溶液解吸磷含量高于添加次序相反的处理,Olsen P含量差异不显著。

The shaking experiments at 25℃ were conducted to study the effect of diatomite on phosphorus(P) availability of water-soluble phosphate(monocalcium phosphate,MCP) in ferrosols in order to research and develop the technology for increasing P efficiency.The results indicated that diatomite application significantly decreased P adsorption in ferrosols,and increased water-soluble P concentration,the phosphorus concentration desorbed by 0.01 mol/L CaCl2 and Olsen P concentration at 0.31 mg P/g soil and 1.25 mg P/g soil,which increased with diatomite application increasing.The results were attributed to the big porosity,the great specific area,and a large amount of OH groups in diatomite.The application order between diatomite and MCP in ferrosols affected P availability. The water-soluble and desorbed P concentrations in the treatment that diatomite wasadded before MCP in soil were higher than that in the treatment that MCP was added before diatomite in soil,but Olsen P concentrations in the treatments were insignificantly different.