Contribution of root respiration to total soil respiration during non-growing season in mine reclaimed soil with different covering soil thicknesses
Abstract An accurate assessment of root respiration in mine reclaimed soil is important for effectively evaluating mining area ecosystem. This study investigated dynamic changes in root respiration and contribution of root respiration to total soil respiration (Rr/Rt ratio) during the non-growth season in mine reclaimed soil with different covering soil thicknesses. According to covering soil thicknesses, the study area was divided into four sites: 10-25 cm (site A), 25-45 cm (site B), 45-55 cm (site C) and 55-65 cm (site D). From November 2017 to April 2018 (except February in 2018), the soil respiration, root respiration, temperature at 5 cm, water content and root biomass were measured. The results showed that soil temperature and root respiration exhibited similar diurnal and monthly variations. The root respiration was strongly influenced by soil temperature during the non-growing season, which showed an exponential and positive relationship with soil temperature (P<0.001). The root respiration varied with the covering soil thickness and was the greatest with the covering soil thickness at 25–45 cm. The Rr/Rt ratio also exhibited monthly variations. During the non-growth season, the mean value of the Rr/Rt ratio were 51.15% in mine reclaimed soil. The study indicated that root respiration was the primary source of soil respiration and important to estimate the potential of emission of soil CO 2 at regional scale in mine reclaimed soil.