徐淮地区石灰性土壤供磷特性的研究

徐淮地区石灰性黄潮土全磷含量不低,而有效磷含量很低,因此研究本地区土壤的供磷特性、土壤中磷的固定和磷肥的残效、以及土壤中原有磷的活化等是很有意义的。本文是研究工作的第一部分即土壤的供磷特性。 试验土样共11种,采自淮阴、睢宁和铜山县,通过温室盆栽试验,并应用吸附等温曲线和动力学的解吸方程,研完了土壤供磷的强度、数量、缓冲容量和释放速率诸因素。试验结果表明,11种土壤溶液磷浓度均在0.1ppm左右,低于临界指标0.2ppm,除8号土外,土壤有效磷水平均较低,黑麦草生长和磷肥效应均与土壤活性磷水平呈明显相关。树脂提取的磷量和Cowell-P均可作为徐淮地区石灰性土壤供磷的数量指标。树脂提取磷的方法,不仅能提供土壤供磷的数量指标,也能反映土壤供磷的速率。

STUDIES ON THE PHOSPHORUS SUPPLYING CHARACTERISTICS OF THE CALCAREOUS SOILS IN XUZHOU-HUAIYIN DISTRICT

The quantity, intensity, buffer capacity and rate factor of soil P availability for 11 calcareous soils were measured by chemical and physicochemical methods and the amount of phosphorus uptaken by rye grass was obtained by pot experiment. The results indicated that phosphorus concentration of soil solution was around 0.1 ppm P which could not satisfy the requirement of rye grass. The quantity factor (resin P, E value and Cowell-P) was significantly correlated with P uptake by rye grass and predicted the status of soil P of these soils satisfactorily. Because of low level of labile P in these soil the buffering capacity (MBC and EBC), calculated by twosur face Langmuir equation, was negatively correlated with P uptake by rye grass.