长期施肥对红壤旱地磷组分及磷有效性的影响

为提高红土红壤磷的有效性和肥料磷的利用率，设立长期定位试验，研究了红壤旱地不同施肥条件下土壤磷素的变化规律。结果表明：长期施磷，特别是磷肥和有机肥配合施用能明显提高土壤全磷（PT）、无机磷、有机磷、Olsen-P和Bray-P含量。在施磷的条件下，土壤磷的积累主要表现为Ca2-P,Ca8-P和Al-P增加。土壤中Olsen-P和Bray-P含量与土壤中各磷组分的相关性以Ca2-P最好，Al-P和Ca8-P次之，O－P最差，土壤Olsen-P和Bray-P含量与作物产量显著正相关。

The Effects of Long Term Fertilization on Chemical Fractions and Availability of Inorgauic Phosphate in Red Soil Upland

The status of soil P in long term different fertilization in red soil upland was studied. The results show that soil total P (P T), inorganic P, organic P, Olsen P and Bray P are high in MNPK, 1.5 (MNPK), MNPK (Soybean) and M treatments, followed by NP, PK, NPK, and SNPK treatments, and low in the treatments without P (N, NK and CK 2). When the P is applied, the main characteristic of P accumulation in soil is that the contents of Ca 2 P Ca 8 P and Al P increase. The relativity of Olsen P and Bray P with Ca 2 P is the highest, followed by P T, Al P and Ca 8 P, and the lowest with O P. In red soil region of southern China, Olsen P and Bray P are two preferable measurement indexes to express the availability of soil P, and both of them are related to crop yield.