氮形态转化对豆科植物物料改良茶园土壤酸度的影响

Effect of Legume Plant Materials Ameliorating Tea Garden Acid Soil as Affected by Nitrogen Transformation

采用室内培养试验方法研究了添加紫云英、刺槐叶和豌豆秸秆对酸性茶园红壤酸度的改良作用,探讨了培养期间豆科植物中氮形态转化对土壤酸度改良效果的影响。结果表明,3种豆科植物可不同程度提高酸性茶园红壤的pH,培养试验结束时土壤pH的增幅与植物物料灰化碱的含量相一致。豆科植物物料中氮的形态转化影响其对土壤酸化的改良效果,有机氮的矿化导致土壤pH增加,而矿化形成的铵态氮通过硝化反应释放质子,抵消了植物物料对土壤酸度的部分改良效果。添加植物物料使土壤交换性盐基阳离子含量明显增加,土壤交换性铝含量明显减少。

A laboratory incubation experiment was carried out to investigate effects of application of Chinese milk vetch shoot, black locust leaves, and pea stalks on acidity of an Uhisol from a tea garden, as affected by nitrogen transformation in these organic materials. Results show that the application increased soil pH to a varying extent compared with control. The extent tallied with the amount of ash alkali in the plant materials. The more the ash alkali in the plant materials, the greater the increase in soil pH. Nitrogen transformation affected the effects of these plant materials ameliorating soil acidity. Mineralization of the organic N in the plant materials consumed H^＋ , thus raising soil pH, while nitrification of NH4^＋ - N from mineralization of organic N released H^＋ , thus lowering soil pH, which somewhat offset the effect of plant materials ameliorating acid soil. The application of the plant materials increased soil exchangeable base cations and decreased soil exchangeable Al significantly.