新疆地带性土壤磷吸附特性影响因素研究

Influencing Factors on Phosphorus Adsorption Characteristics of Zonal Soils in Xinjiang

【目的】分析新疆南、北疆地带性土壤灰漠土和棕漠土的土壤磷吸附特性及磷最大吸附量与土壤基本理化性质的关系,筛选影响新疆地带性土壤吸附固磷能力的主要土壤性质。【方法】采集新疆北疆灰漠土和南疆棕漠土样品,进行磷等温吸附试验。【结果】灰漠土和棕漠土的磷等温吸附曲线都很好地拟合了Langmuir等温吸附曲线。北疆灰漠土最大吸磷量随着土壤pH值、粘粒含量的增加而增加;随着土壤有机质含量的增加呈现明显下降趋势。棕漠土的最大吸磷量随着土壤pH值、Ca CO3含量、粘粒含量的增加而增加。两种地带性土壤吸附固磷能力与土壤游离氧化铁、全磷、速效磷含量无显著相关性。【结论】影响灰漠土和棕漠土的吸附固磷能力的土壤性质包括粘粒含量、有机质含量、碳酸钙含量及pH值。棕漠土碳酸钙含量高达20%左右,pH值也高于灰漠土,导致棕漠土比灰漠土具有更强的吸附固定磷的能力,供试南疆棕漠土最大吸磷量平均为1 087.59 mg/kg;北疆灰漠土平均为820.77 mg/kg。

Objective The phosphorus absorption characteristics of the grey desert soils and the brown desert soils were studied to clarify the relationship of the highest P sorption capacity and the soil basic proper-ties, thus screening the main soil properties affecting the adsorption capacity of phosphorus in Xinjiang s zonal soils.[Method] The samples of grey desert soil in northern Xinjiang and brown desert soil in southern Xinjiang were collected and the isothermal adsorption experiments were carried out .[Result] Phosphorus isothermal ad-sorption curve of the zonal soils in Xinjiang were well fitting the Langmuir isothermal adsorption curve. With the increase of clay contents and pH values, phosphorus adsorption capacity of the grey desert soils in northern Xinjiang increased. High organic matter contents of grey desert soils was not benefitial to phosphorus adsorp-tion. The calcium carbonate content of the brown desert soils affected directly phosphorus adsorption capacity by pH value and the CaC03 contents. The phosphorus adsorption capacity of grey desert soils and brown des-erts soils had no obvious relationship with the content of free Fe oxides, Olsen - P and total phosphorus.[Conclusion] Because brown desert soil has higher content of CaC03 and pH value than that of grey desert soils, it has stronger phosphorus adsorption ability than grey desert soils. The maximum P adsorption capaci-ties （Xm） of the brown desert soil in southern Xinjiang is average 1,087. 59 mg/kg and that of the grey desert soil in northern Xinjiang is average 820.77 mg/kg.