【摘要】 第四纪红色粘土母质发育起来的黄壤性水稻土,二十多年来大量施用磷肥,磷在耕层富集。耕层全磷含量平均0.048%,有效磷含量平均11.6 ppm,分别比底土层高1.7倍和7.5倍,比荒地表层高2.1倍和28.4倍。黄壤性水稻土无机磷形态为混合分布型,Al-P、Fe-P、Ca-P、O-P分别占无机磷总量的5.9%,30.6%,28.7%和34.8%。小麦、水稻分蘖期测定的A值与产量和植株吸磷量相关,能表示土壤磷素有效性的高低。A值与土壤Fe-P和Ca-P相关,表明这两种磷酸盐是稻麦的主要磷源。Olsen法可作为测定黄壤性水稻士有效磷含量的标准方法。更多还原

【Abstract】 The paddy soil from Quaternary red clay is generally deficient in P. Owing to phosphate fertilizer having been successively applied for more than 20 years, P is concentrated in topsoil in which the total P is 0.048%, and the available P is 11.6 ppm on the average. It is 1.7 times and 7.5 times higher than those in subsoil, and 2.1 times and 28.4 times higher than those in topsoil of waste soil with scarce vegetation respectively.The distribution of various fractions of P in the paddy soils was closely related with the zonality of main soil group on which the paddy soils were developed. The organic P was about 35.4%. The Al-p, Ca-p, Fe-p and O-p were about 5.9%, 30.6%, 28.7% and 34.8% respectively. The organic P and non-occluded P increased after rice season under submerged condition, while they decreased afterwheat season in dry farming.The A values were measured by ³²P during the tillering stage of wheat and rice. They were related with the yield and the amount of P uptaken by crop, and also with the content of Fe-p, Ca-p, in the soils which were considered as the main P resousces for wheat and rice.The correlation analysis between four methods of chemical test of available P and the responses of plant or the A values indicates that Olsen method can reflect the availability of P in soil. The Al-Abbas method is worth of being brought into consideration only for rice.更多还原