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本文选择了浙江、江苏15个性质变化范围较大的土壤样品,研究在两种支持电解质、不同pH条件下对磷酸根的吸持反应。结果表明,加碱提高强酸性土壤的pH值,导致交换性铝的水解和羟基铝聚合物的生成,增加对磷的吸持。磷酸根同酸性土壤的反应,可促进交换性铝的水解,释放出H~+,降低体系的pH。在CaCl_2介质中,当pH>6时,可能有磷酸钙类盐形成,使溶液中磷浓度显著降低。有机质对土壤吸持磷有重要影响。在低pH下有机质通过与Al~(3+)形成络合物,阻碍溶液中A1~(3+)的水解,并与磷酸根竞争羟基铝化合物表面的反应点位,从而降低酸性土壤对磷酸根的吸附量。
In this paper, 15 soil samples with a wide range of changes in properties were selected in Zhejiang and Jiangsu Provinces to study the adsorption of phosphate on two kinds of electrolytes and pH conditions. The results showed that adding alkali increased the pH value of strongly acidic soils, resulting in the hydrolysis of exchangeable aluminum and the formation of aluminum-aluminum polymers, and increased the uptake of phosphorus. The reaction of phosphate with acidic soil can promote the exchangeable aluminum hydrolysis, release H ~ +, reduce the pH of the system. In CaCl 2 medium, when pH> 6, calcium phosphate salts may form, which may cause the concentration of phosphorus in the solution to decrease significantly. Organic matter has a significant impact on soil phosphorus uptake. At low pH, organic matter forms a complex with Al3 +, hinders the hydrolysis of A1 ~ (3+) in the solution and competes with phosphate for the reaction site on the surface of Al-Al compound, Root adsorption capacity.