Effects Of Light-felling On Soil Greenhouse Gas Emission From Korean Pine Forest Soil In Non-growing Season

Soil greenhouse gas emission in non-growing season may be very important for us to understand how effected by cutting interference.By using static chamber technique and gas chromatography during non-growing season in temperate Maoer mountain of China,the soil greenhouses gases fluxes(CO2,CH4,and N2O)and related environmental factors(such as soil temperature,soil moisture,soil organic carbon and so on)were observed simultaneously under the different light-felling manners(contrast,no cutting;the half light-felling,cutting 50%of broad-leaved trees in canopy;the whole light-felling,cutting 100%of broad-leaved trees in canopy).That reveals the influence law of cutting interference on non-growing season soil greenhouse gases emission and its main controlling factors.The research contents and results were listed as follows.1.The soil temperature of the light-felling significantly decreased than the contrast during non-growing season(0.31?1.03 ?),mainly vitiating in freezing period(0.10?1.27?)and frozen period(0.50?1.93?).During freezing period,soil organic carbon of the upper layer of the light-felling significantly decreased by 21.2?35.2%,that of bottom layer significantly increased 29.5?35.7%;During frozen period,soil moisture of meddle layer of the whole light-felling significantly decreased by38.2%;During thawing period,soil moisture of bottom layer of the light-felling significantly decreased by29.8?35.1%,nitrate nitrogen content of upper layer significantly decreased by 54.3?56.1%,ammonium nitrogen content increased by 20.0-32.4%.2.The mean values of soil CO2 fluxes in the non-growing season were 42.03?54.45 mg CO2·m-2·h-1 for the temperate Korean pine forest.The light-felling treatments significantly decreased non-growing emissions of CO2 by 21.0%?22.8%.The main decreased phase in the non-growing season is freeing period where significantly decreased emissions of CO2 by 29.9%?43.5%and thawing period where significantly decreased that by 19.8%?21.4%.3.The mean values of soil CH4 fluxes in the non-growing season were-15.08?-12.60?g CH4·m-2·h-1 for the temperate Korean pine forest.The light-felling treatments decreased non-growing absorption of CH4 by 16.0%?16.4%,and significantly decreased thawing absorption of CH4 by 21.8%?34.3%.4.The mean values of soil N20 fluxes in the non-growing season were 21.71?28.37 lag-N2O·m-2·h-1 for the temperate Korean pine forest.The emissions of N2O during non-growing significantly decreased by 23.5%,used the whole light-felling treatments,and decreased by 11.2%,used the half light-felling treatments.This mainly occurs during the thawing period which decreased 8.3%?25.4%and significant in the whole light-felling treatments.5.The results also reveal that light-felling increased correlation between soil CO2 fluxes and soil temperature,soil moisture,nitric nitrogen and ammonium nitrogen,while decreased correlation between it and soil organic carbon;increased correlation between soil CH4 fluxes and soil moisture,soil pH,soil organic carbon,ammonium nitrogen,while decreased correlation between it and nitric nitrogen;increased correlation between soil N2O fluxes and soil temperature,while decreased correlation between it and nitric nitrogen and ammonium nitrogen,and changed the positive and negative correlation between it and soil pH.6.That contributing to annual cumulative(CO2?CH4?N2O)is 11.7%?14.2%?13.1%?17.0%.63.9?72.6%,respectively.The contribution of CO2 of the light-felling treatments decreased by 21.0%?22.8%and that of CH4 by 16.0%?16.4%,that of N2O by 23.5%and 11.2%,compared with the contrast during non-growing season.The light-felling treatments decreased annual cumulative contribution of CO2 by 1.4%?2.5%,that of CH4 by 0.7%?3.9%,but increased that of N2O by 2.4%?8.7%.Compared with the contrast until 40 years of light-felling,GWP(global warming potential)of growing season decreased by 5.0-10.0%,that of non-growing season decreased by 21.0?21.7%,that of annual decreased by7.6?11.7%.Therefore,the effect of light transmission on the greenhouse gas emission in the forest soil is to be carried out in the forest management practice.