伊犁河上游典型草地生态系统氮磷含量及化学计量特征

【目的】了解伊犁河上游典型草地养分限制状况,为不同草地类型群落营养循环及植物-土壤养分管理提供理论依据,也为该区域生态环境的改善提供科学依据。【方法】通过野外调查采样和室内分析测定,采用相关性分析方法,分析了不同类型草地群落植物-土壤氮、磷、钾含量及化学计量学特征。【结果】研究区不同草地类型植物群落植物地上部分和地下部分根系的氮、磷、钾含量变异较大,山地草甸草原和高寒草甸植物地上部分氮含量荒漠草原、半荒漠草原和高寒草甸的氮含量;荒漠草原和半荒漠草原植物地下部分根系的氮含量山地草甸草原、山地草甸和高寒草甸的氮含量;不同草地群落类型植物地上部分的P含量与植物N/P比值呈显著负相关,土壤N与土壤P含量、土壤P含量与土壤N/P比值分别呈显著正相关,土壤N和土壤N/P比值极显著相关,其相关系数为0.983。【结论】研究区土壤氮素缺乏,可以考虑在草地生长过程中适当添加氮肥。

Stoichiometry of nitrogen and phosphorus and the content in grassland ecosystem in the upper reaches of Hi River

Objective] To identify the nutrient limitation of typical grassland in the upper reaches of Ili River on the basis of stoichiometry characteristics of nitrogen (N) and phosphorus (P) in grassland ecosystem,which provides theoretical basis for nutrient cycling and plant-soil nutrient management of different grassland communities and scientific basis for the improvement of ecological environment in this area.Method] Combined field investigation and laboratory analysis,the ecological stoichiometry of nitrogen and phosphorus contents in plants and soils from the typical grassland ecosystems were obtained.Result] The results showed that the contents of N,P and K with above ground plant and under ground root varied greatly.The N contents of above ground followed an order as:mountain meadow and steppe alpine meadow ＞ desert steppe,semi-desert steppe and alpine meadows;the order of N contents of plant underground roots were semi-desert steppe and desert steppe ＞ mountain meadow steppe,mountain and alpine meadow.Different types of grassland ecosystems in plant above-ground P contents had a significantly negative correlation with the N/P ratio of plant.The soil N and soil P contents,soil P contents and soil N/P ratio had a significantly positive correlation.The soil N content was positively correlated with the soil N/P ratio with a correlation coefficient of 0.983.Conclusion] The soil lacked N in the study area.It is suggested appropriately to add N fertilizer for improving the grassland productivities.