砂土供磷特性及磷肥效应研究

砂土供磷特性及磷肥效应的研究结果表明，砂土磷素形态以无机磷为主，有机磷甚少，仅占全磷含量的８．８４％。无机磷占９１．１５％，无机磷形态组成以磷酸钙为主，Ｃａ－Ｐ平均为无机磷总量的８６．１％，Ｏ－Ｐ占９．６％，Ａｌ－Ｐ占３％，Ｆｅ－Ｐ占１．３％。各种形态无机磷与速效磷的关系为：ｙ（速效磷）＝４９．３０ｘ１（ＡＬ－Ｐ）＋２１．８５４７ｘ４（Ｃａ－Ｐ）－３．４２０９，表明Ａｌ－Ｐ、Ｃａ－Ｐ对砂土速效磷的

CHARACTERS OF PHOSPHORUS SUPPLY AND RESPONSE TO PHOSPHATIC FERTILIZER IN SANDY SOILS

The study on characters of phosphorus supply and response to phosphatic fertilizer showed that inorganic p and organic P accounted for 91.12% and 8.87% respectively. In the former Ca-P,O-P, Al-P and Fe-P accounted for 86.1%,9.6%, 3.0% and 1.3% respectively. The relation between inorganic-P forms and rapidly available phosphorus (RAP) could be described by y(RAP)=49.30x_1(AL-P)+21.8547x_4(Ca-P)-3.4209, which indicated the significance of Al-P and Ca-P to RAP and the feasibility that iron and aluminum phosphates and calcium phosphates served as soures to soil P. The growth and decline of total P and available P deponded on P balance in soils. The changes of P forms in fertilizers aapplied relied on soil properties. The great effect of fertilizer P occurred at the early growth stage of plants. At the middle and late stages, plant took up more soil P. P-fertilizer efficiency in coarse and fine sand soils was 41.1% and 17.7% respectively, higher, than that in light sand soil.