荒漠草原植物-土壤氮素分配及其季节动态

THE DISTRIBUTION AND SEASONAL DYNAMIC OF PLANT-SOIL NITROGEN IN DESERT STEPPE

1987～1988年在内蒙古乌盟达茂旗伊克乌素采用半微量凯氏定氮法对石生针茅荒漠草原植物和土壤中氮贮量、分配及其动态进行的研究结果表明,土壤是荒漠草原氮素的巨大贮存库,每公顷贮氮素8390.08～9878.72公斤,0～60厘米土层中氮素呈“倒金字塔”型分布,贮量随时间变化不明显。群落地下部是荒漠草原植物氮素的主要贮存器官,其贮量每公顷为218.60～329.01公斤,并随时间变化呈四次曲线变化,9月中旬达到贮量高峰;随着植物的生长,荒漠草原植物地下部与地上部氮素贮量比率逐渐下降,但到植物枯黄后又迅速上升。

The authors had carried out the preliminary research of the nitrogen storage, distribution and seasonal dynamic of Stipa klemenzii desert steppe with semimicro-Kjeldahl's measure method in Yikewusu, Damao Banner, Wulanchabu League, Inner Mongolia during April 1987-1988.The results showed that soil was large storage pool of the nitrogen in the desert steppe and the nitrogen storage was 8390.08-9878.72kg/ha, the nitrogen distribution in the soil layer was'Inverted Pyramid' shape, the change of soil nitrogen was not obvious as time changes, under ground of the community was the main storage organ of the plant nitrogen in the desert steppe, and the nitrogen storage of the under ground was 218.60-329.02kg/ha, the under ground nitrogen changed on fourth power curve and reached peak in Mid-September, the ratio of under ground and above ground nitrogen storage of the desert steppe plant gradually declined as plants growtr, but the ratio of under and above ground nitrogen storage speedily rose after plant withered.