天山北坡林沿土壤养分含量的区域差异特征研究

以天山北坡为研究区域, 采用野外调查与试验分析相结合的方法, 选取5个土壤养分指标: 有机质、速效氮、速效磷、速效钾和总盐, 应用多元统计分析方法, 分析了天山北坡3个区段(昭苏-特克斯、新源-巴音布鲁克、巴里坤-伊吾)林沿土壤不同层位(0~5 cm、5~20 cm、20~40 cm)养分含量的分布特征及差异性。结果表明: 天山北坡西段(昭苏-特克斯、新源-巴音布鲁克)土壤养分含量比天山北坡东段(巴里坤-伊吾区域)高。3个区段不同深度土壤有机质、速效氮、速效磷、速效钾含量均存在明显差异, 其中0~5 cm土层有机质、速效氮、速效磷、速效钾的平均含量均比5~20 cm、20~40 cm高; 5~20 cm土层有机质、速效氮、速效磷、速效钾的平均含量均比20~40 cm高; 总盐含量不具有明显的垂直分层现象。按全国第2次土壤普查标准, 天山北坡3个区段土壤均属肥沃级。昭苏-特克斯区段、新源-巴音布鲁克区段0~5 cm、5~20 cm、20~40 cm土壤养分各指标含量变化具有一定的规律, 而巴里坤-伊吾区段土壤养分各指标含量变化具有良好的独立性。天山北坡西段(昭苏-特克斯、新源-巴音布鲁克)植被类型较多, 植被覆盖度较高, 土壤较为肥沃, 大部分区域为夏牧场, 人类活动以放牧为主, 对该区段土壤要防止过度放牧所造成的植被退化与水土流失。天山北坡东段(巴里坤-伊吾)因土壤中砾石较多, 植被类型较少, 植被覆盖度较低, 人类活动包括放牧、林业种植与旅游, 与西段相比东段土壤的养分含量较低, 所以应以保持生境原貌为主, 避免人为扰动后的生境退化。

Regional differences in soil nutrient content along the forest edge in the northern slope of Tianshan Mountains

In this study, field investigation and laboratory analyse were carried out to gain a comprehensive insight into five kinds of soil nutrients (organic matter, available nitrogen, available phosphorus, available potassium and total salt) in three sections of the northern slope of Tianshan Mountains - the Zhaosu-Tekesi, Xinyuan-Bayinbuluke and Balikun-Yiwu sections. Multivariate statistical analysis method was used to study the characteristics of nutrient distribution in different soil profile layer (0~5 cm, 5~20 cm, 20~40 cm) in different sections of the northern slope of Tianshan Mountains. According to the standard of the Second National Soil Survey, variational characteristics of fertility and nutrient contents of different soil profiles in the sections were analyzed. Also variations in soil nutrient contents were clarified. Furthermore, quantitative comparison of nutrient contents among different sections was performed. The results showed that soil samples collected from the western sections (Zhaosu-Tekesi and Xinyuan-Bayinbuluke) had much higher nutrient contents than those from the eastern section (Balikun-Yiwu) of the northern slope of Tianshan Mountains. There were obvious differences in contents of organic matter, available nitrogen, available phosphorus and available potassium in the soil layers among different depths in the three sections. The average contents of organic matter, available nitrogen, available phosphorus and available potassium in the 0~5 cm soil layer were higher than those in the 5~20 cm and 20~40 cm soil layers. Also these variables were higher in the 5~20 cm soil profile layer than in the 20~40 cm soil profile layer. However, total soil salt content was not significantly different vertically across the soil profile. Based on the Second National Soil Survey standard, soils on the northern slope of Tianshan Mountains were relatively fertile. While changes in the amounts of soil nutrient contents in the 0~5 cm, 5~20 cm and 20~40 cm soil layers in Zhaosu-Tekesi and Xinyuan-Bayinbuluke sections followed a certain regular pattern, which in Balikun-Yiwu section was irregular. In most part of the western part of the northern slope (Zhaosu-Tekesi, Xinyuan-Bayinbuluke) is large summer pastures with various vegetations and hgiher vegetation coverage, where soils is fertile. It was recommend to protect the soils from overgrazing and random perturbations in order to avoid soil erosion. It was also critical to ban setting up of exploration platforms in larger slope areas. Also the low vegetation cover and gravel soil in the east part of the northern slope (Balikun-Yiwu) induced lower soil nutrient content comparing to the west part. It was therefore important to maintain original habitats and avoid anthropogenic disturbances that could induce habitat degradation.