模拟酸雨对水稻土磷素动态变化的影响

Effect of simulated acid rain on the dynamics of phosphorus in paddy soil

采用室内模拟实验,分析不同强度的酸雨下水稻土p H值、磷素的动态变化,探讨不同酸雨对水稻土磷素变化的影响。结果表明,当模拟酸度为3.5、4.5、5.5的酸雨淋溶40 d过程中,水稻土p H值没有显著影响,说明水稻土具有一定的缓冲能力。而水稻土中全磷变化不大,速效磷含量变化显著,呈现下降的变化趋势,且在一定酸度的酸雨(p H=5.5)淋溶下水稻土中速效磷含量最低。随酸雨酸度的增强,水稻土中微生物量磷和酸性磷酸酶活性均呈先增强后降低的趋势。研究揭示p H≥4.5的酸雨可以促进水稻土中微生物生物量磷活性,当酸雨p H>3.5时可以促进水稻土中酸性磷酸酶的活性;高酸度的酸雨(p H<4.5)对水稻土中微生物量磷有抑制作用,当酸雨p H≤3.5时可以抑制水稻土中酸性磷酸酶活性。

Acid rain pollution is a serious env＇tronmental problem in the world, especially for the phosphorus deficiency in paddy soil. The present study aims to investigate the impact of simulated acid rain upon the dynamics of soil phosphorus （total phosphorus, available phosphorus, soil microbial biomass phosphorus （SMB-P） and phosphatees activity） and soil pH in paddy soil. Results showed that soil pH and total phosphorus in the paddy soil did not significantly changed with the acid rain leaching at pH levels of 3.5, 4.5, 5.5 over a 40-day simulation period, indicating a buffering capacity of paddy soil to acid rain. However, the available phosphorus content changed significantly, which tended to decline. Of the three levels of the simulated acid rain, the available phosphorus content was the lowest when the pH was 5.5. As the increase of acid rain acidity, both SMB-P and phosphatees activity tended to increase and then to decrease. Our study indicated that simulated acid rain with pH ≥4.5 and pH〉3.5 could help to increase the content of SMB-P and phosphatees activity, respectively. But the high-strength acid rain gradually restricted the population and activities of soil microbes.