Primary controls of soil respiration have been understood for decades while there is a lack of knowledge about the variability of these controls across the landscape. The effect of natural environmental gradients, a result of topography, has a direct effect on many of the controls of soil respiration. We investigated soil respiration across a small high elevation forested watershed in north central West Virginia. Automated instrument nests were placed in three different locations covering a variety of terrain and vegetation. Each nest measured soil air CO2 concentrations (5 cm), soil temperature and soil water content on 30-minute intervals for one year.
Results/Conclusions
Results show that unlike previous studies done across riparian-hillslope transitions, soil respiration does not differ significantly between sites in relation to topography. With precipitation evenly distributed throughout the year, soil moisture is relatively consistent leaving temperature as the primary control on both long and short time scales. Seasonal temperature variations show the greatest influence with little variation between sites. One exception was a ridgetop site under a deciduous canopy with a dense Rhododendron subcanopy. Leaf drop in combination with topography allowed the site to maintain higher soil temperatures later in the growing season, resulting in elevated soil air CO2 concentrations. Unlike our other deciduous site, the subcanopy continued to shade the area allowing the soil moisture content to remain consistent after the other sites had started to decrease. These factors led to a soil respiration that peaked at 2177ppm higher than the other 2 sites and remained higher than the others for three months. These results have demonstrated that vegetative cover may play a greater role than previously thought in determining seasonal and short-term soil respiration patterns.
