[Soil respiration in temperate secondary forest and Larix gmelinii plantation in Northeast China].

ABSTRACT

With Li-6400-09 chamber, the soil respiration rate in adjacent stands of temperate secondary forest and Larix gmelinii plantation in Maoershan Mountain of Heilongjiang Province was measured from May to October, 2006. The results showed that similar to the variation of soil temperature, the daily pattern of soil respiration could be expressed as a one-humped curve. Over the study period, soil respiration rate varied from 0.43 to 7.26 micromol CO2 x m(-2) x s(-1) in secondary forest, and from 0.63 to 4.70 micromol CO2 x m(-2) x s(-1) in L. gmelinii plantation. The maximum soil respiration rate occurred from July to August, and the minimum in October. From May to August, soil respiration rate was obviously higher in secondary forest than in L. gmelinii plantation. The respiration rate of litter layer during the study period varied from -0.65 to 1.26 micromol CO2 x m(-2) x s(-1) in secondary forest, and from -0.43 to 0.47 micromol CO2 x m(-2 ) x s(-1) in L. gmelinii plantation. Soil respiration had a strong exponential correlation with soil temperature, especially the temperature at 5 cm depth. The Q10 value at 5 cm depth was 3.61 and 3.07, respectively in secondary forest and L. gmelinii plantation. There was a significant correlation between soil respiration and the soil water content at 10-20 cm depth in secondary forest, but less correlation was observed between them in L. gmelinii plantation.