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应用X射线衍射和化学分析等手段研究了红壤、砖红壤和黄棕壤中氧化铁类型及其与磷吸附和解吸的关系。结果表明:①黄棕壤中的氧化铁是针铁矿型,砖红壤和红壤是以赤铁矿为主、棕红壤是以针铁矿为主的针-赤混合型。②针铁矿的MCD值一般小于赤铁矿的MCD值,前者的比表面积大,后者的小。砖红壤中的赤铁矿晶体薄,红壤中的厚。③针铁矿型氧化铁的磷吸附量明显高于针-赤混合型氧化铁的磷吸附量,并随粘粒中G/(G+H)值增大而提高。赤铁矿晶体愈薄,吸附的磷量愈少。④磷的解吸率随氧化铁中G/(G+H)值增加而降低,赤铁矿形貌对磷的解吸率影响不明显。
The types of iron oxide in red soil, brick red soil and yellow brown soil and their relationship with phosphorus adsorption and desorption were studied by means of X-ray diffraction and chemical analysis. The results showed that: (1) the iron oxide in yellow brown soil was goethite type, the red brick and red soil were mainly hematite, and the brown red soil was needle-red mixed type mainly composed of goethite. ② The goethite MCD value is generally less than the hematite MCD value, the former large specific surface area, the latter small. Hematite crystal brick thin red soil, red soil thick. ③ The gypsum-type iron oxide has higher phosphorus adsorption capacity than that of the needle-red mixed iron oxide, and increases with the G / (G + H) value of the clay. Hematite crystal thinner, the less the amount of adsorbed phosphorus. ④ The desorption rate of phosphorus decreased with the increase of G / (G + H) in iron oxide, and the effect of hematite morphology on the desorption rate of phosphorus was insignificant.