The Study Of Soil Respiration And Component Of Three Forest Types In Lanling Small Valley

Soil respiration is an important part for the Global carbon cycle, this is also a hot and hard point for this topic.The most urgent task is finding out the soil respiration in different area and the percentage of soil respiration componment for total respiration.Forest ecosystem is a vital carbon sink,the soil carbon pool of the forest ecosystem is an important componment for the main carbon processes in the terrestrial ecosystem.Lanlingxi small valley is located in the Three Gorges Reservoir region,so the forest ecosystem in this valley has a significant meaning in the ecology.The typical forest style was the coniferous fores,the broad-leaved forest and the conifer-broadleaved forest in this area.We made some measure to study the soil respiration in these forest types with trenching-plot and infrare gas exchange analyzer approaches.The results was that:(1) The diurnal change of the soil total respiration in three forest types was same,but their average value was different.The order of the diurnal change of the soil respiration was:coniferous forest> conifer-broadleaved forest>broad-leaved forest,and the value was 2.95μmol.m-2.s-1,1.77μmol.m-2.s-1,1.74μmol.m-2.s-1 respectively.(2)The monthly change of the soil total respiration in three kinds of forest types is similar.From the August to December, the soil respiration decreased gradually,and the least value came in December,the value in next April was higher.During the whole experiment time,the order of the soil respiration in three kinds of forest types was that:conifer-broadleaved forest>coniferous forest>broad-leaved forest,and the value was 2.05μmol.m-2.s-1,1.76μmol.m-2.s-1.1.79μmol.m-2.s-1,respectively.(3)The percentage of the soil respiration components in different kinds of forest was similar.In these three forest types,the biggest percentage was animal and microbe in the soil, it occupied about 45%-63%,and the second was root respiration,about 24%-33%,the smallest was the litter respiration,about 11%-24%.(4)Correlation between soil respiration in time variation and temperature on 5cm in different forest types was different.In daily soil respiration,the coniferous forest and the broad-leaved forest had a significant positive correlation,and in monthly soil respiration,coniferous forest and conifer-broadleaved forest had a correlation. (5) Correlation between soil respiration component and temperature on 5cm in different forest types was different.In these three kinds of forest,soil litter respiration, respiration of animal and microbe in soil had significant correlation,but the correlation of root respiration was not significant.(6) Correlation between soil respiration and humudity on 5cm in different forest types was complex,there was not consistent rule.