风干对土壤主要无机磷组分的影响

Effects of Air-Drying on the Inorganic Phosphorus Forms in Soils

选择含磷量差异较大的黄棕壤、水稻土和酸性红壤种植黑麦草、白羽扇豆、荞麦、油菜和籽粒苋等不同植物,并于植物生长90 d后采集新鲜土样,测定其风干前后的主要无机磷组分。结果表明,不同土壤无机磷总量及组成间存在极大差异。风干过程可增加黄棕壤和水稻土无机磷总量,降低红壤无机磷总量。无机磷总量的最大改变值可达原有量的70%左右。风干过程对不同土壤的不同无机磷组分消长的影响不一。它导致黄棕壤Al-P减少,O-P 和Ca-P增加;水稻土Al-P 和Ca-P增加,Fe-P 与O-P 不变;红壤 Al-P与Fe-P增加,Ca-P不变,O-P明显减少。栽培不同植物对无机磷组分在风干过程中的变化也存在影响。作者认为,在进行不同组分磷有效性研究时,采用新鲜土样所得结果更为可靠。

After 90 days' cultivation of five different plants (rye grass, lupin, buckwheat, rape, amaranth), fresh samples of three soils (yellow brown soil, paddy soil, red soil) were collected and contents of several main inorganic phosphorus forms were measured before and after air-drying. The results clearly indicated that total inorganic phosphorus and their composition differed signficantly among soil types. The air-drying process increased the total inorganic phosphorus in yellow brown soil and paddy soil, while decreased that in red soil. The total inorganic phosphorus could even vary to 70 % of the value before air-drying. After air-drying, the inorganic phosphorus forms in different soils changed to different extends. As for yellow brown soil, Al-P decreased, while O-P and Ca-P increased. As for paddy soil, Al-P and Ca-P rose, while Fe-P and O-P remained unchanged. As for red soil, Al-P and Fe-P increased, Ca-P remained unchange and O-P reduced obviously. Cultivation of different plant materials in soil had effects on inorganic phosphorus forms during the process of air-drying. Therefore, in chemical study of soil phosphorus, the application of fresh soil samples can provide more reliable results