Temporal Variation of Soil CO_2 Flux under Different Fertilizer Treatments in Vegetable Field

Characteristics of soil CO2 efflux under different fertilizer treatments were investigated by the method of CO2 absorption into alkaline solution in a vegetable plot of Fuzhou suburb,and the relationship between soil temperature and CO2 emission was also studied.The results showed that soil CO2 flux was higher during the night than the day at the seedling stage and early development stage of amaranth;but was opposite at the late development stage,and decreased as time.Soil CO2 flux for seven fertilizer treatments was the highest at seedling stage,which were respectively 2 379.08,2 482.93,2 129.94,1 299.02,1 890.04,2 293.61,3 029.99mg·m-2·d-1 for CK and all treatments.The lowest CO2 flux was observed at late development stage of amaranth.Among different fertilizing treatments,the lowest CO2flux(209.96 mg·m-2·d-1)was recorded in chemial fertilizer and longacting fertilizer basal application treatment,and the highest CO2flux(3 029.99 mg·m-2·d-1)in 1/2organic fertilizer(basal application)+1/2chemical fertilizer(N and P fertilizer dressing application,and K fertilizer bascal application)+long-acting fertilizer(dressing application)treatment,indicating that chemial fertilizer and longacting fertilizer basal application fertilizer treatment was suitable for vegetable field management in Fuzhou.Meanwhile,by exponential regression analysis,the significantly positive correlation was found between soil CO2 efflux and soil temperature at 15 cm depth under seven fertilizer treatments.