短期增温对亚高山草甸生物量和土壤呼吸速率的影响

Effects of short-term simulated temperatureenhancement on biomass and soil respirationrate of subalpine meadow

摘要:

以滇西北亚高山草甸为研究对象,利用开顶式生长室(OTC)提高土壤温度模拟全球气候变暖,探讨增温对夏季和冬季草地土壤水分,土壤呼吸速率和植被生物量等方面的影响。结果表明:在开顶式生长室的作用下,滇西北亚高山草甸地表年均温度较对照提高了1.56℃,冬季增温效果好于夏季。增温显著提高了草地的地上生物量(P <0.05),比对照高出148.76 g/m2。同时增温促进了根系向10~20 cm 土层扩展。在夏季和冬季,增温处理和对照的土壤呼吸速率均呈现单峰曲线,在14∶00时出现峰值,夏季的最高值为5.66 μmol/(m2·s),冬季为2.79 μmol/(m2·s),夏季的土壤呼吸速率较冬季高出2.87 μmol/(m2·s)。相关性分析表明,土壤呼吸速率与土壤温度呈显著正相关(P <0.05),土壤温度和土壤含水量则呈现出了极显著的负相关(P <0.01)。

Abstract:

The open top chambers (OTCs) were introduced to increase soil temperature in order to exploreeffects of global warming on soil moisture,plant biomass and soil respiration rate of subalpine meadow in northwesternYunnan province.The results indicated that average soil surface temperature was increased by 1.56℃compared with the control;warming effects was more obvious in winter than in summer.Moreover,the temperatureenhancement obviously increased the aboveground biomass(P <0.05),which was 148.76 g/m2 higherthan the control.At the same time,the increase of temperature promoted the expanding of root system into 10to 20 cm soil layer.The soil respiration rate of warming treatment and control in both summer and wintershowed a single peak curve.The maximal value appeared at 14∶00,and the maximal soil respiration rate in summerwas 5.66 μmol/(m2·s) while it was 2.79μmol/(m2·s) in winter.The soil respiration rate in summerwas 2.87 nm/(m2·s) higher than that in winter.Correlation analysis indicated that the correlation between soilrespiration rate and soil temperature was significant (P <0.05),however,a significant negative correlation wasobserved between soil temperature and soil water content (P <0.01).