Root respiration and its relation to nutrient contents in soil and root and EVI among 8 ecosystems, northern China

Root respiration is a critical and uncertain component of ecosystem carbon budgets. We assessed whether variation in root respiration at a reference temperature were associated with that of root and soil nutrient contents and enhanced vegetation index (EVI) among 8 ecosystems, including three forests, two shrublands, two meadow grasslands, and one meadow in a forest-steppe ecotone in northern China. Mass specific root respiration was positively related to root nitrogen content when data from all the different classes of root diameter were pooled. Area specific root respiration increased with soil available nitrogen through increasing fine root biomass. Beside the effect of soil or root nutrient contents, mass specific respiration of fine roots followed EVI patterns, suggesting that root respiration was strongly dependent on photosynthesis. A simple respiration-EVI relationship may provide a convenient way to estimate root respiration and has potential applications in quantitative spatial extrapolation.