模拟增温对寒温带兴安落叶松林土壤及空气温湿度的影响

Effect of Simulated Warming on Soil and Air Temperature and Humidity in Larix gmelinii Forest in Cold Temperate Zone

采用开顶室(OTC)模拟增温的方法,设置增温组(OTC,模拟增温)和对照组(CK,无处理),通过连续1 a(2019年11月—2020年10月)的野外原位观测试验,探讨了模拟增温对兴安落叶松(Larix gmelinii)林内各层土壤(5、10、15、20 cm)以及地上1.5 m处空气温湿度的影响。结果表明:(1)与对照相比,OTC内地下5~20 cm土壤年均温度依次增幅1.18、1.83、1.69、1.29℃,地上空气温度增幅1.18℃;土壤年均湿度较CK依次降低2.31%、1.85%、1.14%、5.07%,空气湿度降低2.15%。土壤年均温度在各层次间无显著差异。20 cm的土壤湿度最高,且显著高于其他土层。(2)土壤和空气月均温度在模拟增温和对照处理下均呈“先下降后上升”的趋势;增温处理下的空气温度高于对照。土壤湿度月变化呈现出生长季(6—9月)变化波动大,非生长季(10月—翌年5月)变化波动小的趋势。(3)模拟增温处理下,5、10 cm土壤温度在秋季具有显著差异。(4)模拟增温和对照处理下,夏季夜间的15、20 cm土壤湿度与5、10 cm间的差异具有显著性。综上,开顶室能够有效改变微气候环境,对地上1.5 m、地下5、10、15、20 cm土壤有一定的增温降湿效应。

The method of simulated warming in open top chambers(OTC)is used,and the two groups are set up,which are the warming group of the open top chamber(OTC)and the control group of the control check(CK).Through the continuous field in-situ observation and experiment over one year(Nov 2019-Oct 2020),the effects of simulated warming on soil layer(5,10,15 and 20 cm)and air temperature and humidity at 1.5 m above ground in Larix gmelinii forest are researched.The results show that:(1)Compared with CK,the average annual soil temperature ranging from 5 to 20 cm underground in OTC shows an increase of 1.18,1.83,1.69,and 1.29℃while the aboveground air temperature is 1.18℃higher.The average annual soil humidity is respectively lower than CK at 2.31,1.85,1.14,and 5.07%while the air humidity shows a reduction of 2.15%.The average annual soil temperature among different soil layers is similar without significant differences.The soil humidity of the 20 cm soil layer is the highest which is remarkably higher than that of other soil layers.(2)The monthly average temperature of soil and air in OTC and CK suggests a tendency of decreasing before increasing.The air temperature in OTC_(i)s higher than that of CK.The monthly average humidityof soil shows that it fluctuates greatly in the growing season(from June to September)and changes little in the non-growing season(from October to May of the following year).(3)Under the simulated warming environment,a wide gap exists in the soil temperature of soil layers at 5 and 10 cm during autumn.(4)In both OTC and CK,it demonstrates an obvious difference between 15-20 and 5-10 cm soil layers in terms of soil humidity on summer nights.In conclusion,the open top chamber can effectively change the microclimate and has a certain influence on increasing temperature and reducing the humidity of the soil layers 1.5 m above ground and 5,10,15 and 20 cm underground.