Effect of fire, plowing and N addition on soil carbon dynamics in Songnen grassland, northeast China

Abstract

This study measured soil respiration rate and soil organic carbon (SOC) concentration in Songnen grassland for treatment of Fire, Plowing and N addition and discussed the effect of these treatments on soil respiration and soil carbon stocks. Our results showed that the diurnal soil respiration rate has the same change trend. Compared with Native grassland, Plowing and Fire treated grassland increased 25.8% and 9.2% of the soil respiration rate. Over 65% of total soil C stocks was stored in the 0-30 cm soil depth. The treatment of Fire and Plowing decreased 7.97% and 8.58% of SOC stocks related to Native grassland in entire profile. The carbon stock was highest at low N addition level (0 and 5 g/m2 ), and was lowest at high N addition level (15 and 25 g/m2 ), which indicated that high N addition level may be having a negative effect on SOC stock in Songnen grassland.