模拟酸雨对桉树人工林土壤养分流失的影响

Effects of Simulated Acid Rain on Soil Nutrient Loss of Eucalyptus Plantation

以3年生桉树纯林土壤为研究对象,采用土柱淋溶法模拟酸雨沉降,配置pH值为3.0、4.0、5.6、6.0(CK)的酸雨溶液,分析桉树人工林土壤养分淋失情况。结果表明:土壤全N、硝态N经酸雨处理后含量增加,平均增加量达123.8%,其中pH 3.0处理后全N含量增加最多,为原来的2.8倍;pH 3.0与pH 5.6、pH 6.0处理后硝态N差异性极显著;铵态N含量与处理液pH值呈正相关,其中pH 3.0处理后含量最低,减少了37.1%。土壤P素含量与酸雨处理液pH值呈正相关,且处理前后差异性极显著;速效P各处理的平均流失量达54.2%,所有元素中流失量最大,流失量值最高的处理pH 3.0达77.8%,而pH 6.0处理流失量也达23.25%。土壤盐基离子含量与酸雨处理液pH值呈正相关,其中交换性Ca流失量最大,各处理平均流失量达45.2%,在pH 3.0处理下的流失量达79.8%,是所有元素和处理中流失量最大值;其次是交换性Na,交换性K受酸雨处理液影响较小。盐基离子流失量从大到小排序为:交换性Ca^(2+)>交换性Na+>交换性Mg^(2+)>交换性K+。

The soil of 3 years old Eucalyptus forest was selected for simulating acid deposition by soil col- umn leaching method （pH value was 3.0, 4. 0, 5.6, 6. 0, respectively）. The loss of nutrient content of Eucalyptus plantation soil was analyzed. The results showed the contents of total nitrogen and nitrate ni- trogen increased by 123.8% （mean value） after the treatment of acid rain. The greastest increase was the total N content with pH 3.0 acid treatment, which was 2. 8 times more than the origination. Nitrate- N content with pH 3.0 acid treatment was significant difference compared with pH 5.6 or pH 6. 0 acid treatment. Ammonium N content was positively associated with the pH value of treating solution, and the least content is pH 3.0 acid treatment among these treatments, which reduced 37. 1%. P content in soil was positively associated with the pH value of treating solution, and it showed a significant difference before or after treatment. The mean loss of available P content with different treatment reached 54. 2%. The biggest loss was P among all the elements. The P content loss with pH 3. 0 treatment reached 77. 8%, while the P content loss with pH 6. 0 treatment reached 23.25%. The content of base ions in soil was al-so depended on the pH value of treating solution. Among the four metal elements, Ca had the biggest loss and the mean of leaching amount was up to 45.2%. The loss reached 79.8% after pH 3.0 acid treat- ment. The loss of base cations decreased in the order Ca^2＋ 〉 Na^＋ 〉 Mg^2＋ 〉 K^＋.