藏北高原高寒草地土壤有效养分含量研究

选择藏北高原高寒草地不同海拔的12个样地对土壤有效养分进行研究,结果表明:在海拔4 480m优势植物为嵩草(Kobresiaspp)、苔草(Carex tristachya)的高山草原土速效氮含量较高;人工种植的在海拔4 530m的紫花苜蓿(Medicago sativa)和海拔4 300m燕麦草(Arrhenatherum elatius)有效磷含量较高;高山草原土壤速效钾含量较高;在海拔4 466m优势植物为早熟禾(Poasp.)的高山草原土有效铜和有效铁含量较高;在海拔4 481m高山草甸土的裸地有效锰含量较高;在海拔3 473m原生植被覆盖的亚高山草原土有效锌含量较高。有效氮、磷、铜、锌和锰在高山草原土中分布异质性较亚高山草原土、高山草甸土和高山荒漠土差;速效钾在各种类型土壤中分布异质性较均匀;有效铜在亚高山草原土中分布异质性较差。总体而言,藏北高原高寒草地中土壤有效养分含量高低和分布异质性,受到海拔高度、土壤质地、地上植被、人为开发利用及气候变化等多种因素影响。

Characteristics of soil available nutrient of alpine meadow in The northern Tibet Plateau

Soil available nutrients of alpine meadow in The northern Tibet Plateau were tested. The results showed that soil available nitrogen content was high at an altitude about 4480m with dominant plants of Kobresia spp,Carex tristachya while soil available phosphorus content was high at an altitude of 4 530 m with growth of Medicago sativa and altitude 4 300 m with Arrhenatherum spp of manpower plant. Soil available potassium content was high in all the tested sample. Samples,from altitude 4 466 m alpine steppe soil with dominant plants P. spp, had higher available copper and available iron content than other tested samples while higher available manganese content with altitude 4 481 m alpine meadow soil bare ground and higher levels of available zinc con- tent with altitude 3 473 m subalpine steppe soil covered with native vegetation. The heterogeneity distributions of available nitrogen, phosphoru of sub-alpine steppe soil, alpine s, copper, zinc and manganese in the a meadow soil and alpine desert soil w lpine grassland soil were poorer than those bile available potassium heterogeneity uni- fomrmity in all types of soil. Available copper in sub-alpine soil were poor heterogeneity distribution. Overall, soil available nutrient level and heterogeneity distributional The northern Tibet Plateau were influenced by alti tude, soil texture, ground vegetation,human exploitation and climate change and other factors.