Soil-atmosphere greenhouse gases (CO2, CH4 and N2O) exchange in evergreen oak woodland in southern Portugal

Plant, Soil and Environment

Rosa A.P.¹  Castaldi S.¹  Lobo-do-Vale R.¹  Cruz C.¹  Shvaleva A.¹  Chaves M.M.¹  Pereira J.S.:¹ 

关键词: climate change;    drought;    Mediterranean;    precipitation;   

DOI  :  

学科分类：农业科学（综合）

来源: Czech Academy of Agricultural Sciences

【 摘 要 】

A 10–20% decrease in annual precipitation is predicted in the Mediterranean basin, and in particular to the Iberian Peninsula, with foreseen effects on the exchange of soil-atmosphere greenhouse gases (GHGs; CO2, CH4, and N2O). To simulate this scenario, we setup an experimental design in the particularly dry period of 2008–2009 using rainfall exclusion and irrigation, to obtain plots receiving 110% (538 mm), 100% (493 mm) and 74% (365 mm) of the natural precipitation. Soil CO2 fluxes showed a strong increase from summer to autumn as a consequence of increasing soil heterotrophic respiration that resulted from rewetting. Fluxes of N2O were negligible. According to our data, soil was a permanent CH4 sink independent of the soil water content (in the range between 6–26% WFPS – water-filled pore space) and of soil temperature (in the range of 7–28°C), supporting the concept that seasonally dry ecosystems (Mediterranean) may represent a significant sink of atmospheric CH4. The study provides evidence that the 26% decrease or 10% increase in the ambient rainfall from annual precipitation of ca 500 mm did not significantly affect soil functionality and had a limited impact on soil-atmosphere net GHGs exchange in evergreen oak woodlands in southern Portugal.

【 授权许可】

Unknown