祁连山区高寒草原土壤肥力特征及肥力因子间的关系(简报)

<title>Studies on the characteristics of soil fertility and relationshipamong nutritive factors in alpine grassland soil of Qilian mountains

对祁连山区的8个草原土壤类型进行典型采样分析,结果表明养分含量差异很大,可分为高含量和低含量2组(A组和B组),前者包括亚高山灌丛草甸土、高山草甸土、山地黑钙土和亚高山草甸土,有机质含量在14%以上,而后者包括山地栗钙土、山地棕钙土、亚高山草原土和高山草原土,有机质含量在4%以下。其中以亚高山灌丛草甸土最高,达19.61%;而以高山草原土最低,为1.77%。pH值变化范围为7.2～8.4。阳离子代换量的变化趋势亦同有机质,最高为亚高山灌丛草甸土,最低为亚高山草原土,分别为65.61和10.64m·e·/100g。全量养分的特点为低磷高氮富钾,全氮含量为0.097%～0.981%,全磷为0.045%～0.105%,全钾为2.13%～4.05%。速效养分以贫磷为特征,A组土壤略高为13.2×10-6～28.2×10-6,而B组则为1.8×10-6～4.9×10-6。除全钾、速效钾和pH值外,其他指标两两之间具有较好的相关性。特别是有机质和阳离子代换量,与其他指标的相关系数均在0.844以上,可将有机质含量作为土壤营养状况的首选判断因子。建议在进行草原培育或建植人工草地时应注意补充磷素,对高山草原土、亚高山草原土还应适当施氮或补播豆科牧草。

<Abstrcat> Studies in this paper showed that the nutrient factors varied very much among soil types in Qilian mountains and the studied 8 soil types could be grouped into two groups (Group A and B) according to nutritive factors. Group A included subalpine shrub soil, alpine meadow soil, alpine chernozem and subalpine meadow soil. The organic matter content (OMC) in this group was above 14%. Group B included alpine chestnut soil, alpine brown soil, subalpine steppe soil and alpine steppe soil and their OMC were below 4%. Among 8 soil types, the subalpine meadow soil had the highest OMC (19.61%) and alpine steppe soil had the lowest (1.77%). The pH value of 8 soil varied from 7.2 to 8.4. The variance trend of Cation Exchange Capacity (CEC) was similar with the OMC. The highest was subalpine meadow soil (65.61 m·e·/100g) and the lowest was alpine steppe (10.64 m·e·/100g). The characteristic of total nutrients was low phosphorus, high nitrogen and relative rich potash. However, the available nutrients were characterized with low available phosphorus. It was slightly higher in group A (between 13.2×10-6 and 28.2×10-6) and quite low in Group B (between 1.8×10-6 and 4.9×10-6). All nutritive factors had significant relationship each other except total potash, available potash and pH value. Especially the relationship coefficients of OMC and CEC with other factors were above 0.844. The nutritive condition suggests that phosphorus should be applied during grassland improvement and artificial grassland establishment. For alpine steppe soil and subalpine grassland soil, nitrogen fertilizer or legume should be used at the same time.