Soil Respiration Of Temperate Secondary Forest And Larix Gmelinii Plantation In Northeastern China

Larix is one of main wood in our Country, has very importance status in northeast forest.May to October in 2006, With Licor6400-09 champer method,soil respiration in adjacent stands of temperate secondary forest and Larix gmelinii plantation were measured at Mao'r mountain of Heilongjiang province.The results showed that difference of the daily pattern and seanonal pattern is prominence.The daily pattern of soil respiration rate could be expressed as a one-humped curve in two plots, which was similar to the variation of soil temperature.The peak value at 15:00～17:00, the paddy value at 1:00～4:00 in secondary forest. The value was delayed 4-6 hour in Larix gmelinii plantation. Over the studies period, soil respiration rate varied from 0.43 to 7.26μmol·m^-2·s^-1 in secondary forest, from 0.63 to 4.70μmol·m^-2·s^-1 in Larix gmelinii plantation. The maximum soil respiration occurred during July to August and the minimum in October. Soil respiration rate in secondary forest was higher than that in Larix gmelinii plantation, especially May to August. The seasonal dynamics of litter layer respiration rate varied from -0.65 to 1.26μmol·m^-2·s^-1 in secondary forest, from -0.43 to 0.47μmol·m^-2·s^-1 in Larix gmelinii plantation.Proportion of litter layer respiration rate were 2.56% and 9.59% at soil respiration rate in secondary forest and Larix gmelinii plantation. Soil respiration had an exponential correlation with soil temperature in two plots, especially at 5 cm depth in secondary forest. The Q₁₀ value at 5 cm depth was 3.61 in secondary forest and 3.07 in Larix gmelinii plantation.Soil respiration wasn't correlated with soil water content in secondary forest and Larix gmelinii plantation.Soil respiration rate were closely linearity correlated with root biomass(D＜1mm), Oraganic C, Total N,Bulk density, C/N,pH,Tatol P.Soil release C were 835.76 gC·m^-2 and 650.60 gC·m^-2 in secondary forest and Larix gmelinii plantation during May to October. This study show, the soil respiration rate descended When secondary forest change to Larix gmelinii plantation in northeast temperate zone.The root biomass (D＜1mm), Oraganic C, Total N, Total P may change about soil respiration rate.