采用原状土柱进行模拟淋溶实验,比较研究了模拟酸雨和几种低分子量有机酸对红壤pH和交换性Al的影响。结果表明,与去离子水CK相比,pH 3.5和pH 4.5模拟酸雨淋洗后0~10 cm土层pH分别降低了0.27、0.44和0.08、0.18个单位,土壤交换性Al含量分别增加了4.43%和2.38%;而10~50 cm土层pH没有显著变化。柠檬酸、苹果酸和草酸淋洗后0~10 cm土层pH比模拟酸雨淋洗后高0~0.3个单位,土壤交换性Al含量则要低0.08~0.75 cmol/kg。与模拟酸雨相比,100μmol/L柠檬酸、苹果酸和草酸淋洗后10~50 cm土层pH降低幅度基本上<0.1个单位,交换性Al含量增加了6.99%~12.82%;而10 mmol/L柠檬酸、苹果酸和草酸淋洗后10~50 cm土层pH降低幅度达0.02~0.83个单位,交换性Al含量增加了22.45%~34.66%。这意味着低分子量有机酸或许比酸雨在加速土壤酸化方面有更大的威胁。
The effects of acid rain and several low molecular weight organic acids on red soil pH and exchangeable Al was investigated by simulated leaching experiment with undistributed soil column. The results showed that pH in the 0~10 cm soil depth was decreased by 0.27, 0.44 and 0.08, 0.18, and soil exchangeable Al was increased by 4.43% and 2.38%, respectively, after leached with pH 3.5 and pH 4.5 simulated acid rain, compared with deionised water check, while pH in the10~50 cm soil depth was not changed significantly. pH in the 0~10 cm soil depth was higher within 0.3 unit, and soil exchangeable Al was lower 0.08~0.75 cmol/kg in the citric, malic and oxalic acid treatments than that of in the simulated acid rain treatment, respectively. pH in the 10~50 cm soil depth was decreased by about 0.1 unit, and soil exchangeable Al was increased by 6.99%~12.82 % in 100 μmol/L citric、malic and oxalic acid treatments, respectively, compared with simulated acid rain treatment. pH in the 10~50 cm soil depth was decreased by 0.02~0.83 unit, and soil exchangeable Al was increased by 22.45 %~34.66 % in 10 mmol/L citric、malic and oxalic acid treatments, respectively, compared with simulated acid rain treatment. It imply that low molecular weight organic acids may have a greater threaten in accelerating soil acidification than that by acid rain.
李平,王兴祥.几种低分子量有机酸淋溶对土壤pH和交换性铝的影响[J].土壤,2005,37(6):669-673. LI Ping, WANG Xing-xiang. EFFECTS OF LEACHING WITH LOW MOLECULAR WEIGHT ORGANIC ACIDS ON SOIL pH AND EXCHANGEABLE ALUMINUM[J]. Soils,2005,37(6):669-673复制