中文摘要：

土壤渗漏液pH对于亚热带酸性土壤的物质迁移和溶液中物质形态具有重要影响。为了研究亚热带酸性土壤硝化作用释放H^＋与渗漏液pH的关系，以具有不同硝化强度的3个红壤样本为供试材料，分别加入铵态氮0、150和300mgkg^-1，进行112d的室内土柱模拟淋溶实验。结果表明：酸性土壤的渗漏液并不一定呈酸性。土壤渗漏液pH取决于硝化作用产生H^＋的速率与土壤酸缓冲能力的综合作用。当硝化作用使渗漏液中NO3^-浓度升高至一定程度时，渗漏液pH突然下降，这一临界NO3^-浓度与土壤盐基饱和度及加入土壤的铵态氮量呈线性正相关（P〈0．05）。所以，硝化作用最强的旱地土壤，由于其盐基饱和度达81％，渗漏液始终保持中性；而硝化作用不强、盐基饱和度为21％的灌丛土壤，其渗漏液pH可降至4．0以下。

英文摘要：

pH of leachate plays an important role in translocation of matters in the soil and form of substances in soil solution in subtropical acid soils. To study relation between H^＋ released in nitrification and pH of soil leachate in the soils, an indoor simulated leaching experiment was carried out for 112 days using soil samples different in nitrification intensity amended with 0, 150, and 300 mg kg^-1（ NH4HCO3） -N, separately and leached 17 times, once a week. Results show that the leachates from the acid soils were not necessarily acid, and their pH values depended on combined effect of H^＋ release rate from nitrification and acid buffering capacity of the soils. When nitrification brought the concentration of NO3^- in the leachate up to a certain level, pH value of the leachate dropped abruptly. The critical point NO/concentration showed a linear positive relationship （p 〈 0.05 ） with the soil base saturation and the application rate of （NH4HCO3 ）-N. Therefore, leachates from the upland soil highest in nitrification intensity with base saturation 81% remained neutral, while leachates from the soil under shrubbery, moderate in nitrification intensity and 21% in base saturation dropped below 4.0 in pH value.