不同CO2浓度和氮肥水平对稻田呼吸速率的影响OA北大核心CSTPCD

To explore the effects of different CO2 concentrations and nitrogen fertilizer levels on the respiration rate of paddy fields,a field experiment was conducted using 12 open-top chambers.Three levels of CO2 concentration were set:the control(CK,ambient atmospheric CO2 concentration),and CO2 concentrations increased by 120 μmol·mol-1(C1)and 200 μmol·mol-1(C2)compared with CK.Nitrogen fertilizer was set at two levels:low nitrogen application(N1,15 g·m-2)and conventional nitrogen fertilizer(N2,25 g·m-2),with a total of 6 treatments in the experiment.The results showed that under the same nitrogen application level,the respiration rate of the C1N1 treatment decreased by 23.4%(P=0.045)and 49.1%(P=0.010)compared with the CKN1 treatment at the filling stage and wax ripening stage,respectively.During the heading and grain-filling stages,the respiration rates of the C2N2 treatment increased by 12.3%(P=0.009)and 16.8%(P=0.047)compared with the CKN2 treatment,respectively.Under the same level of CO2 concentration,the respiration rates of different nitrogen application levels showed that N2>N1 and showed a significant level during the elongation and heading stages and an extremely significant level during the grain filling stage.In the grain filling and wax ripening stages,the respiration rates of C1N1 treatment decreased by 31.1%(P=0.004)and 42.7%(P=0.010),respectively,compared with C1N2 treatment.This paper demonstrates that the effect of elevated atmospheric CO2 concentration on the respiration rate of paddy fields varies with the growth period,and nitrogen fertilizer reduction can reduce the respiration rate and CO2 accumulation in paddy fields.