不同载畜率和模拟降水对短花针茅荒漠草原生态系统碳交换的影响

Effects of different stocking rates and simulatedprecipitation on ecosystem carbon exchange inStipa breviflora desert steppe

摘要:

为探究不同载畜率和降水对荒漠草原生态系统碳交换产生的影响,采用Li-6400便携式光合仪和密闭式箱法于2016年生长季测定净生态系统碳交换,生态系统呼吸和总生态系统生产力。结果表明:在不同载畜率和降水的处理下,净生态系统碳交换都呈现碳吸收状态;在重度放牧情况下,增水100%处理下的总生态系统生产力显著高出减水50%、自然降水和增水50%处理(P <0.05);在自然降水和增水50%处理下,净生态系统碳交换,生态系统呼吸通量和总生态系统生产力在不放牧和重度放牧之间存在显著差异(P <0.05)。试验证明,载畜率的增加显著降低了生态系统碳交换,模拟降水初期对生态系统碳交换变化不明显。

Abstract:

In order to study the effects of different stocking rates and precipitation on ecosystem carbon exchangein desert steppe,the net ecosystem carbon exchange,ecosystem respiration and gross ecosystem productivitywere measured in the growing season of 2016 by using the portable optical LI-6400and the method of staticchamber.The results showed that: the net ecosystem carbon exchange showed carbon absorption status underthe treatment of different stocking and precipitation;In heavy grazing treatment,the total ecosystem productivityunder 100% water increase treatment was significantly higher than 50% water reduction,natural precipitationand 50% water increase(P <0.05);In the treatments of natural precipitation and 50% water increase,therewas a significant difference in net ecosystem carbon exchange,ecosystem respiration,and total ecosystem productivitybetween no grazing and heavy grazing(P <0.05).Based on the results,it can be concluded that withthe increase of stocking rate,the ecosystem carbon exchange was significantly reduced while the change in ecosystemcarbon exchange during the initial stage of simulated precipitation was not obvious.