滨海土壤I-69杨根际无机磷形态分布及有效性研究

Distribution and Availability of Inorganic Phosphorus Fractions in the Rhizosphere of Populus deltoides cv.'lux' Grown in Marine Soil

对滨海脱盐土壤或轻度盐渍土壤上不同林龄I -69杨根际、非根际无机磷存在形态、数量和有效性进行了研究 ,结果表明 :I -69杨根系活动能明显提高根际土壤供磷能力 ,3、5、11年生I -69杨根际有效磷明显富集 ,富集量分别为3 .87、4.3 2、4.3 5mg/kg ;Ca2 -P在不同林龄I -69杨根际含量明显高于非根际土 ,差异都达到极显著水平 ,R/S随林龄增大分别是 2 .15、2 .5 9、5 .5 4;Ca8-P在 5、11年生I -69杨根际明显富集 ,而Ca10 -P明显亏缺 ;不同林龄I -69杨根际、非根际土Al-P、Fe -P和O -P含量无明显差异 ,盐渍土壤中它们的生物有效性较低。

In the present experiment, the distribution characteristics and availability of inorganic phosphorus fractions in the rhizosphere and non-rhizosphere soil of Populus deltoides cv. 'lux' were investigated. The results showed that (1) Available P was accumulated clearly in the rhizosphere of 3,5 and 11 year-old stands and the accumulation rates were 44%, 96% and 574%, respectively; (2) The contents of Ca 2-P in the rhizosphere of 3,5 and 11 year-old poplar were higher than those in the non-rhizosphere,and the rhizospheric effects (R/S) were 2.15, 2.59 and 5.54, respectively; (3) In the rhizosphere of 5 and 11 year-old poplar, Ca 8-P was accumulated, whereas Ca 10 -P was depleted clearly and the decrease of Ca 10 -P corresponded with the changes of available P, suggesting a stronger consumption in older stands for the P-activation from Ca 10 -P to more available P;(4) There was no obvious difference in Al-P, Fe-P and O-P between rhizosphere and non-rhizosphere soil.