Abstract:The diurnal variation of soil respiration at various growth stages of soybean and the influencing factors are investigated with static dark chamber method and gas chromatograph technique in pot experiment. In the flowering, pod, and grain-filling stage, soil respiration rate was measured consecutively 3 day-nights at 2 hours internal in daytime (6:00~18:00) and 3 hours internal in night (18:00~6:00). In the course of sampling, the temperature in air, on surface, and at 5 cm depth soil were recorded. The soi...