The Soil Carbon Dioxide Flux Of Three Land-use Types In The North Plain Of Huai River

To probe the effect of the soil of poplar planted forestry, crop land and agro-forestry model land to the increasing and the flux of CO2, to find the differences and similarities in the soil CO2 flux among the three different land-use types, and to analysis the reasons and mechanism of the factors that influence the soil CO2 flux, the Licor-8100 Automated Soil CO2 Flux System was utilized to monitor the change of soil carbon dioxide flux of the three land-use types. The soil CO2 flux and the amount of the soil released CO2 of them in was studied systematically from 2009.10 to 2010.12.The results showed that the average diurnal variation of soil CO2 flux of three land-use types in every month and season tends to be identical. The diurnal variation of soil CO2 flux was a typical single peak curve in the every season except that in winter. Because of the influence of poplar, the time that the maximum of the soil CO2 flux appeared in the poplar planted forestry and agro-forestry model was one or two hours late than that in the crop land far away from the poplar planted forestry.The tendency of soil CO2 flux and the amount of soil released CO2 of the three land-use types was the same in the whole year of 2010. The value in summer was biggest, and then in autumn, the smallest was in winter. The overall difference between the value of one land-use type in four different seasons and the value of three land-use types in the same season was significant. But the multiple comparisons of them are not the same.The curve of average amount of soil released CO2 and the soil CO2 flux of every month of the three land-use types in the year 2010 exhibited an inversion "U" shape. The maximum value appeared in July or August in summer, while minimum value appeared in December or January in winter because of the low temperature. The soil CO2 flux value of the poplar forestry and wood land of the agro-forestry model was bigger than that of the crop land, and the value of the agro-forestry model was bigger than that of the crop land, because of the rarely disturbance of soil, more vegetation cover and litter in the poplar forestry and the wood land. And the difference between value of agro-forestry model and crop land was not significant.In the 14 factors that can influence the soil CO2 flux, the influence degree of the macro weather situation factor in the testarea and micro environmental factors of the measuring points was different in different time. The ranges of variation of every micro environmental factor were stationary in one kind weather situation. The influence of the weather to the soil CO2 flux was accomplished by influence of the micro environmental factors.