Abstract: Rate of soil heterotrophic respiration(Rh)of a 40-year-old Robinia pseudoacacia plantation during the minor growing season in the south hilly region of north China were analyzed.The experiments were conducted in Jiyuan city of Henan province from Nov.2009 to Mar.2010,and soil heterotrophic respiration rate was measured by Li-8100 automatic monitoring system.The main results were as follows:(1)the diurnal variation of Rh was not apparent but the daily Rh changed significantly during this season.The averaged Rh was 0.426μmol·m-2·s-1 in the whole minor growing season.(2)Significant relationship was found between Rh and soil temperature at the 5cm depth(P<0.01),which could be well described by exponential equations.Rh increased with the increasing of Ts at the 5cm depth and Q10 was 1.86.Rh was significantly related to soil temperature(Ts) and soil moisture(SW) at 5cm depth.SW was the most important soil physical parameter that effected on Rh through comparing the partial coefficient of Ts and SW at the 5cm depth.

Key words: Robinia pseudoacacia plantation, Robinia pseudoacacia plantation, Minor growing season, Soil heterotrophic respiration