西藏尼洋河中上游流域不同土地利用方式土壤养分含量差异分析

为研究西藏尼洋河中上游流域不同土地利用方式土壤养分含量变化特征,以尼洋河中上游流域耕地、草地和林地为研究对象,采用标准取样法分层采集土壤样品216份(0~10、10~20、20~30 cm),并测定土壤全氮、碱解氮、全钾、速效钾、全磷、速效磷和有机质。结果表明,西藏尼洋河中上游流域土壤有机质、全氮、碱解氮含量,林地>草地>耕地,且三者之间均表现出显著差异(P<0.05)。草地和林地的全钾含量相差不大,速效钾含量林地>草地>耕地。在不同土地利用方式下土壤全量养分和速效养分的分布均表现出一定的表聚性,0~10 cm深度土壤全量养分和速效养分的含量明显高于10~20 cm和20~30 cm,且三者之间表现出显著差异(P<0.05)。研究区3种土地利用方式下林地土壤中的碱解氮平均含量最大,耕地的含量最小。耕地的土壤速效磷平均含量(19.47 mg/kg)显著大于草地(5.73 mg/kg)和林地(5.19 mg/kg)平均含量。上述结果说明长期开展植被恢复能够提升尼洋河中上游流域流域的土壤质量。研究结果为改良该区域的土壤效应提供了基础支撑。

The Difference of Soil Nutrient Content in the Middle and Upper Reaches of Niyang River Basin of Tibet

To study the soil nutrients in the middle and upper reaches of the Niyang river basin of Tibet and explore the spatial variability and distribution characteristics of soil nutrients, 216 soil samples (0-10, 10-20 and 20-30 cm) were taken by standard sampling method in the cultivated land, grass land and forest land, and the content of total nitrogen, alkali-hydrolyzed nitrogen, total potassium, available potassium, total phosphorus, available phosphorus and soil organic matter were determined. The results show that the content of soil organic matter, total nitrogen and alkaline hydrolysis nitrogen in the study area have an order of forest land> grass land>cultivated land, and there are significant differences among the three (P<0.05). There is no significant difference in total potassium content between grass land and forest land, and the available potassium content is forest land> grass land>cultivated land. Under different land use types, the distribution of total nutrients and available nutrients in the soil show certain surface clustering, the content of total nutrients and available nutrients in the soil at the depth of 0-10 cm is significantly higher than that of 10-20 cm and 20-30 cm and the three have significant differences (P<0.05). The average content of alkaly-hydrolyzed nitrogen in the forestland is the highest and that of cultivated land is the lowest in the study area. The average content of available phosphorus in cultivated land (19.47 mg/kg) is significantly higher than that in grass land (5.73 mg/kg) and forest land (5.19 mg/kg). In conclusion, long-term vegetation restoration can improve soil quality in the upper and middle reaches of Niyang river basin, and the study could provide basic support for improving the soil effect in the area.