The release of carbon dioxide (CO2) occurs through soil respiration. However, release of CO2 from soil to the atmosphere is subject to interference from agents such as relief, edaphic and climatic conditions. Thus, this research aimed to quantify edaphic respiration related to edaphoclimatic factors in a toposequence area in Caatinga of Delmiro Gouveia, Alagoas, Brazil. The research was conducted from February 2013 to June 2014, with bimonthly collections during day and night. The soil CO2 losses, temperature measurements, soil water content and rainfall were quantified. We verified that, independent of the evaluated points, CO2 release was higher at night. Half-slope and shoulder were the areas with the highest emissions. Additionally, the CO2 emissions presented annual variation, increasing with the availability of soil water and showing peaks of release in the rainy season. Soil and air temperature had no direct influence on soil CO2 release; however, the highest CO2 emissions occurred when temperatures were moderate and stable. Therefore, the conservation of this unique Brazilian biome is necessary because the impacts of its disturbance can increase the level of CO2 released from the soil, increasing the amount of CO2in the atmosphere.
Elevated in-soil CO2 affects physiology and growth of Pinusdensiflora andQuercusvariabilis seedlings under an artificial CO2 release experiment
