三江源区土地利用方式对土壤氮素特征的影响

发布时间：2019-01-28 11:38

【摘要】：以三江源区曲麻莱县高寒草甸草原、退化高寒草甸草原、退化高寒草原和人工草地4种土地利用方式为研究对象,研究了不同土地利用方式的土壤全氮、有效氮、铵态氮、硝态氮、无机氮总量及比例,结果表明:4种利用方式土壤的氮素含量均处于较低水平,在0~10 cm土层,土壤全氮与有效氮含量表现出相似的规律性,人工草地最高,退化高寒草甸草原最低。与高寒草甸草原相比,退化高寒草甸草原0~10 cm土层全氮和有效氮含量分别降低了52.4%和76.2%,而10~40 cm土层的全氮和有效氮含量却明显增加。对土壤铵态氮和硝态氮含量的研究结果进一步表明,研究区域土壤中无机氮以硝态氮为主,退化导致0~10 cm土层的铵态氮和硝态氮含量降低,退化和人工种植均导致0~10 cm土层硝态氮含量明显降低,而10~20 cm和20~40 cm土层的硝态氮含量明显升高,且这两个土层之间差异不显著,40~60 cm土层又明显降低。因此,退化和人工种植均导致土壤硝态氮沿土壤剖面淋溶下移,并且淋溶主要发生在0~40 cm深度的土壤中。土壤无机氮总量与硝态氮表现出相似的规律性,对土壤无机氮总量和比例的研究也表明退化加剧了土壤氮素的矿化过程。
[Abstract]:Four land use patterns of alpine meadow grassland, degraded alpine steppe and artificial grassland in Qumaali County, Sanjiangyuan County, were studied in this paper. The soil total nitrogen, available nitrogen and ammonium nitrogen of different land use patterns were studied. The results showed that the nitrogen contents of the four utilization methods were all at a low level. In the 0 ~ 10 cm soil layer, the contents of total nitrogen and available nitrogen in the soil showed a similar regularity, and the artificial grassland had the highest nitrogen content, and the total nitrogen content of the soil was similar to that of the available nitrogen content in the 0 ~ (10 cm) soil layer. Degraded alpine meadow steppe is the lowest. Compared with alpine meadow steppe, the total nitrogen and available nitrogen content in 0 ~ 10 cm soil layer of degraded alpine meadow grassland decreased by 52.4% and 76.22%, respectively, while the total nitrogen and available nitrogen content in 10 ~ 40 cm soil layer increased significantly. The results of the study on the contents of ammonium and nitrate in the soil showed that the inorganic nitrogen in the soil was mainly nitrate nitrogen, and the degradation resulted in the decrease of the content of ammonium and nitrate in 0 ~ 10 cm soil layer. Degradation and artificial planting resulted in a significant decrease in nitrate nitrogen content in 0 ~ 10 cm soil layer, but a significant increase in nitrate nitrogen content in 10 ~ 20 cm and 20 ~ 40 cm soil layer, and there was no significant difference between the two layers, and a significant decrease in 40 ~ (60) cm soil layer. Therefore, both degradation and artificial planting resulted in the leaching of nitrate along the soil profile, and the leaching occurred mainly in the soil at the depth of 0 ~ 40 cm. The total amount of inorganic nitrogen in soil showed similar regularity to nitrate nitrogen, and the study on the total amount and proportion of inorganic nitrogen in soil also showed that degradation aggravated the mineralization process of soil nitrogen.
【作者单位】：甘肃农业大学草业学院/草业生态系统教育部重点实验室/中美草地畜牧业可持续发展研究中心/甘肃省草业工程实验室;兰州大学草地农业科技学院;中国科学院西北高原生物研究所;
【基金】：国家自然科学基金项目(31360584) 甘肃省青年科学基金(1506RJYA027)
【分类号】：S153.6

【相似文献】