不同硫酸铝用量对苏打盐碱土磷素形态及吸附特性的影响

Effect of Aluminum Sulfate on the Forms and Adsorption Properties of Phosphorus in Soda Saline-alkali Soil

通过室内模拟盆栽改良试验,研究了硫酸铝的改良效果及施用后对土壤中磷素营养状况的影响。硫酸铝配施磷肥和氮肥对小麦的出苗和生长起着明显促进作用。无机磷分级及相关分析结果表明,施加不同用量的硫酸铝后,各级无机磷平均含量的大小顺序为Ca2-P>Ca8-P>Al-P>O-P>Fe-P>Ca10-P,其中,Ca8-P和O-P是Ca2-P的有效补充。磷的吸附实验表明,各处理土壤磷的等温吸附曲线与Langmuir方程的吻合程度最好,其相关程度达极显著水平。根据简单Langmuir方程,将C/x/m对C作图,得到的是具有一个折点的直线,表明随着磷平衡浓度的不同,土壤对磷的吸附存在着两个不同能量水平的吸附点位。磷的解吸结果表明,在磷平衡浓度较低的条件下,土壤与磷的结合能力较强,大多以固定态磷的形式被吸附,并且,解吸也较困难;随着磷平衡浓度的增加,可交换磷所占的比例增加,有较多的磷可被解吸下来。

Soil indoors mod el experiments were carried out to study effects of aluminum sulfate （Al2 （SO4）3） on effectiveness and forms of phosphorus. The results showed that different Al2 （SO4）3 amounts and the same amounts of phosphate fertilizer and nitrogen fertilizer could obviously promote emergence rate and growth of wheat. Fractions of inorganic phosphorus in improved soils were also studied. The results showed that the sequences of inorganic phosphorus content of soils improved by different Al2 （SO4） 3 amounts were followed CaE-P 〉 CarP 〉 Al-P 〉 O-P 〉 Fe-P 〉 Ca,o-P. Under different Al2（SO4）3 amounts condition, CarP and O-P were the valid complement of Ca2-P. The results of phosphate adsorption showed that the adsorption isotherms were fitted well with Langmuir equation. According to the single Langmuir equation, a plot of C/x/m against C gave a linear relationship that was formed by a broken-line plot under phosphate fertilizer application condition, indicating that the presence of two population of sites that have a differing affinity. The experiment of desorption showed that in low equilibrium phosphorus concentration, phosphorus could be desorbed difficultly; while in high equilibrium phosphorus concentration, phosphorus could be desorbed easily.