棕壤不同粒级微团聚体中磷素的保持与供应

采用对比法对采自辽宁省主要地区 1 8对不同肥力典型棕壤中不同粒级微团聚体内全磷的分布以及对磷素的保持与供应状况进行研究 ,结果表明 ,高肥土壤全磷平均含量为 0 .61 1± 0 .1 83g/kg ,低肥的为 0 .379± 0 .0 95 g/kg ;高肥土壤平均吸附磷量为 1 2 7.1± 37.1 7g/kg ,低肥的为 2 33.2± 4 7.2 8g/kg;解吸磷和解吸率高肥的为 2 6.8± 1 0 .77g/kg和 31 .65± 2 5 .66% ,低肥的为 2 1 .3± 8.98g/kg ,和 9.62± 4 .99% .高肥土壤中各粒级微团聚体的全磷含量、磷素的解吸及其解吸率都高于低肥的对应值 ,其中 ,1 0～ 5 0 μm微团聚体中磷素储量最大 ,<1 0 μm微团聚体在磷素的吸附和保持方面贡献最大 ,因此可以把它们作为棕壤的特征微团聚体 .

Phosphorous Retention and Supply in Microaggergates of Brown Earth with Different Fertility Levels in Liaoning Province

The phosphorous retention and supply capacities changed greatly in microaggreates of brown earths with different fertility level in Liaoning Province. The results showed that the average of total P in soil with high fertility level was 0 611±0 183g/kg,whereas 0 379±0 095g/kg in soil with lower fertility level. The absorbed P was 127 1±73 17mg/kgin fertile samples and 233 2±47 28mg/kg in infertile soils. And the desorbed P and desorption rate were higher in the fertile soil than that in the infertile soil. In different microaggrates, the total P, desorbed P and desorption rate were higher in fertile sample than that in infertile soil. And it was found that the <10μm microaggregate played a great role in the P retention and >10μm microaggregate contributed greatly in the P desorption, which means that the ratio of <10μm/>10μm microaggrate could be as one index of evaluating fertility level in brown earth.