A Study On Soil Respiration Of Typical Forests In Liaoheyuan Nature Reserve Of Northern Hebei

Through the research,we have come to the conclusion:The study area is located in Dawopu forestry station, Liaoheyuan. This study selected typical forest types as the object, using Li-8100 Automated Soil CO2 Flux System to monitor soil CO2 flux and temperature and moisture in different-aged natural secondary Pinus tabulaeformis forest, Larix principis-rupprechtii plantation, Betula platyphylla-Quercus wutaishanica-Populus davidiana broad-leaved mixed natural secondary forest in Liaoheyuan Nature Reserve of Northern Hebei (during growing season in 2013 and 2014).The results showed that:1.The total soil respiration rate and their components rates in six forest types showed a significant monthly variation pattern during the growing season. The total soil respiration rate and their components rates of each forest type increased from initially measured month, reaching the peak in summer, ranging from June to August. Mostly,root respiration rate peaked at August or Sepetember;litter respiration and mineral respiration in most forest stands peaked at June to August during exuberant growing period.When soil temperature got lower,soil temperature played a leading role in soil respiration and its components respiration; During exuberant growing period.the combined effect of soil temperature and soil moisture played a leading role in soil respiration while soil temperature suppress soil respiration..2.Soil respiration components rate’s percentage varied with the forest type.The accountance of mineral respiration rate accounts the biggest part during the two years.The average rate is 59.37% in 2013,and 66.14% in 2014;litter respiration rate accounts the bigger in 2013,and the average rate is 26.63% in 2013,however,in 2014,litter respiration rate dropped corresponding proportion equally with root repiration rate (16.58%、16.62%);the contribution of root respiration rate is the lowest part,which is3.The effect of difference of different forest stands on temperature and moisture is diverse.The variation of soil component respiration in six forest stands may react equally to environmental factors’alterations,hence the sequence of soil component respiration fluctuated litte between the two years.Soil temperature became the main factors of soil respiration in different forest stands,whereas soil moisture was also one of the factors affecting soil respiration rate and its component rate;to different year,the factor directly affected the different soil respiration rate is soil temperature and air humidity.4.Soil respiration rate had a significant exponential correlation with temperature. The combined effect of soil temperature and soil humidity at 5cm soil depth was the dominant factor for both the total soil respiration rate and their components during the growing season, and it could explain 53.4%～86.4% of total soil respiration rate,71.0%～89.7% of litter respiration,42.5%～65.6% of root respiration, 74.1%～92.3% of mineral soil respiration,respectively, in six forest types. By making comparations of Q10 value in total soil respiration and their components:litter respiration>total soil respiration>mineral soil respiration>root respiration; air temperature sensitivity to soil respiration was lower than soil temperature.