The Difference Of Soil Respiration And Its Mechanisms In The Early Stage Of Artificial Regeneration And Silvicultural Plantation

Forest soil respiration is the major CO2source of the forest ecosystem, its small changes will cause changes of CO2concentration in the atmosphere, what’s more, C storage capacity of the forest soil will be influenced. After clear-cutting and slash-burning, soil habitat changes markedly, how will soil respiration responds has attracted much attention. We studied a36-year-old secondary Castanopsis carlesii forest with different managements (logging residues remained, residues burning with high intensity, residues burning with low intensity, no logging residues) after clear-cutting and slash burning in Sanming, Fujian province for ten months. We studied the soil respiration rate and CO2concentration in different layers (10cm,20cm,40cm,60cm,80cm) of the soil profile, and the dynamic changes of corresponding soil respiration (soil layer of10cm,20cm,40cm,60cm), we focused on the response and mechanism of soil respiration and soil respiration in different soil layer to clear-cutting and slash burning. The results showed that:(1) After clear-cutting and slash burning, sites with different managements had higher temperature sensitivity and daily variation than that of the control;(2) Within two months after burning, the soil respiration rate of sites with different managements was much higher than that of the control site, but after two months, the result was opposite, during the whole study period, the order for mean value of soil respiration rate was high intensity burning> low intensity burning> control> logging residues remained> no logging residues;(3) Compared with the control, the soil respiration rate in every soil layer (despite of the lowest layer) in the burning site had increased remarkably, the highest increasing rate is90%;(4) A combination of soil temperature or soil moisture content could explain the daily variation of soil respiration quite well (The maximum R2is0.72), they could also explain the soil respiration in different layers (despite of the lowest layer) of the burning site quite well (The maximum R2is0.75), but they could not explain the soil respiration rate of sites with different managements within two months after burning well (The maximum R2is0.10).(5) There were significant differences in soil respiration among various treatments (P<0.05). Three months after burning, the order of total CO2emission from soil in different treatments was high-intensity burning (411g·m-2)>low intensity burning (368g·m-2)> logging residues remained (249g·m-2)> no logging residues (249g·m-2)>control (246g·m-2). But for the whole study period (10month), the order is control (1187g·m-2)> low intensity burning (1085g·m-2)> high intensity burning (1077g·m-2)> no logging residues (919g·m-2)> logging residues remained (913g·m-2).