毛乌素沙地油蒿枯落物分解对增温的响应

【目的】明确油蒿枯落物分解速率对增温的响应,有助于理解和预测气候变化背景下毛乌素沙地典型灌丛生态系统的碳循环和养分循环。【方法】应用开顶箱模拟增温,以自然状态为对照,结合分解袋法,研究增温对毛乌素沙地油蒿枯落物分解的影响。【结果】模拟增温降低了枯落物分解速率。(1)自2017年5月起至2017年10月实验结束时,增温处理下,油蒿枝条和叶片枯落物质量残余率分别为91.07%和71.73%,而对照处理下,分别为86.08%和60.74%;(2)不同时段不同处理条件下不同种类的枯落物分解速率不同,各影响因子之间存在交互作用;(3)Olson负指数模型结果表明,在模拟增温条件下,油蒿枝、叶枯落物的分解系数k均显著低于对照处理;(4)增温对枯落物细菌多样性和群落结构没有影响。【结论】增温可能减缓干旱半干旱区植物枯落物分解,并且温度对枯落物分解的抑制作用与分解时间和枯落物类型有关。

Response of litter decomposition to warming of Artemisia ordosica in Mu Us Desert of northwestern China

ObjectiveThe response of litter decomposition rate of Artemisia ordosica to warming is helpful to understand and predict the carbon cycle and nutrient cycling of the Mu Us Desert of northwestern China under the background of climate change.MethodThe Open Top Chamber (OTC) was used to simulate the warming, and plant decomposition was put into the mesh bags to explore the effects of warming on the decomposition of Artemisia ordosica litter.ResultThe residual rate of litter quality of each part under the warming treatment was higher than that of control, simulated warming reduced the rate of litter decomposition. (1) From May to October in 2017, under the warming treatment, the residual rates of the twig and letters were 91.07% and 71.73%, respectively, but under control, the two indicators were 86.08% and 60.74%; (2) different types of litter decomposition rates were different under varied treatment conditions at different time periods, and there were significant interactive effects between each influening factor; (3) the Olson negative index model showed that under the warming treatment, the decomposition coefficient k of the twigs and leaves of Artemisia ordosica litter was lower than that of control. (4) Warming didn’t affect the bacterial diversity and structure of litter.ConclusionWarming may slow down the decomposition of plant litter in arid and semi-arid areas, and the inhibition of warming on litter decomposition is related to decomposition time and litter types.