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采用1965年Bremner提出的土壤有机氮分级方法,对25年有机肥与化肥定位试验中的土壤各剖面层次有机氮组成进行分级。结果表明,长期施用化肥和有机肥对河西灌漠土不同剖面土壤全氮和有机氮各组分有显著影响,施肥对不同形态有机氮的影响取决于肥料种类。土壤全氮及有机氮各组分含量均随土层深度的增加而降低,但有机氮各组分占全氮的比例随土层深度增加的变化却无明显规律。不同土层间土壤有机氮各组分含量的差异主要存在于0～100cm土层,100～180cm差异较小,180cm以下差异很小。与单施化肥相比,在0～100cm土层,有机肥与化肥配合施用后显著提高了土壤全氮和酸解性氮的含量。在酸解性氮中,氨基酸态氮和酸解未知氮显著增加,在0～40cm土层氨基糖态氮含量也有所提高。与不施肥相比,施用氮肥显著提高了0～200cm所有土层的土壤全氮、酸解性氮与非酸解性氮的含量。在酸解性氮中,化学氮肥显著提高了0～200cm所有土层氨态氮的含量,对氨基酸氮、氨基糖氮和酸解未知态氮影响较小。
Based on the classification method of soil organic nitrogen proposed by Bremner in 1965, the composition of organic nitrogen in each section of 25-year organic fertilizers and chemical fertilizers was graded. The results showed that long-term application of chemical fertilizers and organic fertilizers had significant effects on soil total nitrogen and organic nitrogen fractions in different sections of Hexi Irrigation Desert Soil. The effects of fertilization on different forms of organic nitrogen depend on the type of fertilizer. The content of total nitrogen and organic nitrogen in soil decreased with the increase of soil depth, but there was no obvious regularity that the proportion of organic nitrogen in total nitrogen increased with soil depth. The content of organic nitrogen in different soil layers mainly exists in 0 ~ 100cm soil layer, with small difference between 100 ~ 180cm and little difference below 180cm. Compared with the single application of chemical fertilizers, soil organic matter and chemical fertilizer application significantly increased soil total nitrogen and acid nitrogen content in 0 ~ 100cm soil layer. In acid labile nitrogen, the content of amino nitrogen and acidolysis unknown nitrogen increased significantly, and the content of amino sugar nitrogen in 0-40cm soil layer also increased. Compared with non-fertilization, the application of nitrogen fertilizer significantly increased soil total nitrogen, acid-labile nitrogen and non-acid nitrogen in all soil layers from 0 to 200 cm. In acid-soluble nitrogen, chemical nitrogen fertilizer significantly increased the content of ammonia nitrogen in all soil layers from 0 to 200 cm, and had little effect on amino acid nitrogen, amino sugar nitrogen and unknown state nitrogen.