Soil respiration flux of four land-use types in non-growing season in North Plain of Huai River

To probe the effects of four land-use types, i.e. wood land and wheat land of agro-forestry model, poplar plantation abandoned land and wheat land, on the increase and the flux of CO2，the licor-8100 Automated Soil CO2 Flux System was used to monitor the change of carbon flux of soil from the four land-use types. The soil respiration (Rs) of them was studied systematically. The results showed that the monthly variation and diurnal variation of Rs of four land-use types were lower and had no significant change. The average soil respiration flux of wheat land of agro-forestry model was the smallest and the contribution rate of respiration flux of soil was 22.55%, which was 3.02% less than that of crop land, 6.00% less than that of wood land of agro-forestry model and 0.85% less than that of the plantation abandoned land. The soil respiration flux of agro-forestry model was 2.85% less than that of the plantation abandoned land and was the same with that of wheat land. The relationship of soil respiration and the factors was not significant in October, but became significant with temperature inereasing and other factors in January and February.