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以陕西关中灌区红油土和渭北旱塬红垆土为供试土样,研究不同土层氮素的矿化和硝化作用.结果表明,除0～20cm土层外,红油土20～40cm及40～60cm土层,红垆土20～40cm土层,仍存在着相当数量的可矿化氮,60cm或40cm以下低而稳定.铵态氮的硝化作用也具有明显的层次性:60cm以上土层硝化作用快,以下慢,这种变化与硝化细菌的分布一致.总体上看,红油土中氮素的矿化和硝化作用强于红垆土.铵态氮肥在粘粒含量少、有机质含量高土层中的迅速减少主要归咎于硝化,而在粘粒含量多、有机质含量少的土层,主要取决于矿物固定
The results showed that except for 0 ~ 20cm soil layer, the red soils of 20 ~ 40cm and 40 ~ 60cm soil layer, 20 ~ 40cm soil layer of red soil, there are still a considerable amount of mineralizable nitrogen, low and stable below 60cm or 40cm.The nitrification of ammonium nitrogen also has a significant level: 60cm Above the soil nitrification fast, slow below, this change and the distribution of nitrobacteria consistent .In general, the nitrogen mineralization and nitrification of red soil is stronger than red soil.Ammonium nitrogen fertilizer in the clay content less , The rapid reduction of high organic matter content in the soil layer is mainly due to nitrification, whereas in soils with a high clay content and low organic matter content, it depends mainly on mineral fixation