控制性增温和施氮对荒漠草原土壤呼吸的影响

以内蒙古高原短花针茅(Stipa breviflora)+冷蒿(Artemisia frigida)+无芒隐子草(Cleistogenes son-gorica)的荒漠化草原为研究对象,野外自然条件下进行的生态系统控制性增温与施肥实验,以研究温度和氮素的增加对荒漠化草原植物群落的土壤呼吸作用可能产生的影响。研究结果发现,实验期间内增温处理样地0cm,7.5cm,15cm,30cm和50cm土壤平均温度与对照样地相比,平均增加了1.32℃,0.92℃,0.88℃,0.80℃,0.74℃,土壤温度呈现出上层变异性大于下层的规律,不同土层土壤温度的显著增加(P<0.05)说明模拟气候变暖实验的有效性。虽然增温和对照样地不同土层的土壤温度与土壤呼吸速率均呈正相关关系,但无论是季节还是日变化上,近两年的增温作用没有增加土壤的呼吸速率,施氮作用也没有使土壤呼吸作用明显加强。

The effects of experimental warming and nitrogen addition on soil respiration in desert Steppe

We examined the effect of experimental warming and nitrogen addition on a desert steppe,where the constructive species is Stipa breviflora and some companion species with Artemisia frigida and Cleistogenes songorica.The Objectives were to study the increase influences of temperature and nitrogen on soil respiration.Infrared heaters were employed to raise soil surface temperature throughout the May,2006;nitrogen fertilizer(NH4NO3,nitrogen contents is 33%～35%) was applied in rain season of early July.Soil temperatures at depths of 0 cm,7.5 cm,15 cm,30 cm and 50 cm increased by 1.32℃,0.92℃,0.88℃,0.80℃ and 0.74℃ in the warmed plots,there was significant difference(P﹤0.05) between warmed and control plots.Not only seasonal variation but daily dynamics,experimental warming didn't significantly increase the soil respiration rate,although soil temperature at different depths had positive correlation with soil respiration rate.Nitrogen addition didn't enhance the soil respiration rate obviously.