模拟酸雨胁迫对赤红壤磷素形态特征的影响

Effect of Simulated Acid Rain in Situ on Characteristics and Fractionation of Phosphorus in Lateritic Red Soils

通过田间小区模拟酸雨实验,研究酸雨胁迫下赤红壤不同磷素形态变化的方向和程度。结果表明,原位模拟酸雨影响下,一定强度(pH≥4.0)的酸雨胁迫能有效促进有效磷的释放,而当pH<4.0强度酸雨胁迫时有效磷的释放随pH值降低逐渐受到抑制。随酸雨酸度的增强,土壤酸性磷酸酶和微生物量磷均呈现先升高后降低的变化趋势,可见一定强度酸雨胁迫能促进溶磷微生物和磷酸酶活性,而当高强度酸雨胁迫时土壤微生物活动逐渐受到抑制。无机磷组分中Al-P、Ca-P和Fe-P含量均随酸雨酸度的增强而降低,土壤O-P含量没有显著变化。相关分析发现,有效磷含量与微生物量磷、酸性磷酸酶呈极显著正相关,表明此时土壤有效磷变化与有机磷矿化关系最为密切。有效磷含量与各种形态无机磷(Al-P、O-P、Ca-P和Fe-P)含量之间也有较强的正相关性,表明土壤生态系统磷素转化是一个自我调节的动态平衡过程,且在一定条件下可以相互转化。

We investigated the direction and degree of the change of the simulated acid rains in situ on characteristics and fractionation of phosphorus by field experiments, results showed that soil acidification could help to increase the content of soil available P, microbial biomass P and phosphates activity to some extent, but the high-strength acid rain gradually retrained the population and activities of soil microbes. Correlation analysis suggested both the acid phosphates and SMB-P showed large additive effect on the available phosphorus, the relations between the contents of inorganic phosphorus fraction and available P, also showed that there were strong positive correlations between Al-P, O-P, Ca-P, Fe-P and available P. Relations among the other inorganic phosphorus fraction were also close, and all the results indicated that the transformation of phosphorus in soil ecosystem is dynamic balance and self-adjusting, and would be interconvertible under given conditions.