Soil respiration response in different vegetation types at Mount Taihang, China

Abstract

Temperature response of soil respiration depends on the sensitivity and adaptability of soil respiration (SR) for the variation of soil temperature, which will directly influence the terrestrial carbon cycling and extent prediction of global warming. The diurnal and seasonal variations in the temperature response of SR were assessed through continuous measurement during the June 2012–May 2013 with an automated chamber system under three vegetation types (Robinia pseudoacacia, RP; Vitex negundo var. Heterophylla, VN; Artemisia sacrorum, AS) in the hilly region of Mount Taihang, China. Our results indicated that SR exhibited significant seasonal variations in the RP, VN and AS sites (0.15–5.14, 0.14–4.51 and 0.22–5.28μmolm−2s−1). Due to the adaptability for the variation of soil temperature, SR peaked in Aug 2012 and bottomed in Apr 2013, and the adaptability will weaken the relationship between SR and temperature. Because of the differences of plant physiology and environment conditions, temperature sensitivity of soil respiration (Q10) varied among vegetation types. Meanwhile, because of exempted from seasonal complicated factors, average daily Q10 values of the RP, VN and AS sites (1.86, 1.35 and 1.53) were all smaller than the values of annual Q10 (2.12, 3.32 and 2.61), and might better reflect the biological sensitivity of respiration to temperature. Q10 exhibited a strong seasonal variation pattern, and decreased with increasing soil temperature. This result indicates that low temperature may be more important to carbon cycling than higher temperature based on soil respiration results. The study area had low soil respiration rates, enhancing the long term C accumulation in the context of global warming. The seasonal variation of Q10 was primarily driven by soil temperature while soil moisture had little influence on the dynamic for each site based on annual scales. However, due to the complicated relation between soil properties and SR, Q10 value derived from diurnal and seasonal patterns of SR should be used with extreme caution when estimating carbon balance of terrestrial ecosystem.