Soil Respiration And Carbon Balance In Three Different Degraded Forests

Following global change has received much attention, the precise measurement of CO2 flux and its source and sink were more important. Soil respiration is a mainly source of CO2 in the atmosphere and important part of carbon cycle in terrestrial ecosystems. CO2 efflux plays a critical role in carbon exchange between the biosphere and atmosphere. Research on soil respiration at abroad started in early 20 century, and has been concerned until nine decades. As a main source of CO2, soil respiration, especially forest soil respiration, is becoming the focus. Research on soil respiration in China is started lately, and there is only little information on respiration, especially for soil respiration in degraded ecosystems. From 2002, soil respiration and carbon balance were studied in a natural forest of Castanopsis kawakamii (NF) and adjacent monoculture plantations of C. kawakamii (CK) and Chinese fir (Cunninghamia lanceolata, CF) in Sanming Nature Reserve, Fujian. A comprehensive total model about temperature and moist was established to count total soil respiration. The result showed that:(1) The seasonal change of soil respiration in the three forests was Summer> Spring> Autumn> Winter and only one peak was found in a year.(2)The two parameter model equation of soil respiration about temperature and moist are as follows : R=0.6264 e0.0638T W1.3786, r2=0.9281 for CF; R=1.8301 e005257 W1.2032 ,r2=0.9360 for CK; R=5.1855 e0.04057 W1.1738, r2=0.8705 for NF.(3)The equation of various of compartment respiration about temperature and moistare different among the three forests. Respiration of root, forest floor and mineral soil in the CF is R=0.0003309 e0.15737 W2.7858, r2=0.5738: R=0.0008165 c0.06767 W2.7239 r2=0.3566: R=13.5160 e0.02027 W0.4910, r2=0.3215 respectively. The corresponding equations in the CK are R=0.04253 e0.06694T W2.0394 r2=0.5852;R=0.01197 eOO5175T W2.0174 r2=0.3146; R=12.31230 e0.03530T W0.3939, r2=0.3894 respectively. In the NF, the three simulated equations are R=0.2211 e0.06532T W1.743, r2=0.6185; R=0.0003309 e0.1573T W27858 r2=0.4836; R=39.0733 e0.02762T W0.3574, r2=0.1265 respectively.(4)The annual total CO2 flux in the three forest soils are 4.371 tC hm-2 a-1, 6.234 t C hm-2 a-1 and 13.758 t C hm-2 a-1 for the CF, CK and NF respectively.(5)The carbon balance of CF, CK and NF are 1.644 t C hm-2 a-1 10.126 t C hm-2 a-1 and 3.639 t C hm-2 a-1 respectively .which showed that the three forest play...