利用~(32)P 测定红黄壤土对小麦、水稻不同生育期的供磷能力—‘A’值表明:分蘖期‘A’值与籽实产量极显著相关。小麦拔节期、水稻孕穗期的‘A’值仅与植株吸磷相关。小麦抽穗期、水稻成热期的‘A’值与两者都不相关。因此表明用小麦、水稻做实验,在苗龄6周左右测定‘A’值能灵敏地估计土壤磷的有效性。 Using ~ (32) P to determine phosphorus supply ability of red and yellow loam to wheat and rice at different growth stages-’A ’value indicated that’ A ’value at the tillering stage was significantly correlated with seed yield. At jointing stage of wheat, the ’A’ value at the booting stage of rice was only related to phosphorus uptake by plants. At heading stage, the value of ’A’ in rice is not related to both. Therefore, experiments with wheat and rice showed that the determination of ’A’ at seedling age of about 6 weeks can sensitively estimate soil phosphorus availability.