华北低山丘陵区绿豆和玉米农田土壤呼吸动态研究

Study on the Dynamics of Soil Respiration in the Croplands of Mung Bean and Maize in Hilly Area of North China

不同作物覆被下的土壤呼吸研究是农田生态系统碳循环的重要研究内容。基于气体红外分析技术,2006年对华北低山丘陵区绿豆和玉米农田的土壤呼吸进行观测,并分析两种农田生态系统土壤呼吸的日动态和季节变化特征及其影响机制。结果表明,绿豆全生育期(7月15日-10月3日)的平均土壤呼吸速率为2.11μmol·m-2·s-1,显著大于玉米的1.90μmol·m-2·s-1(P<0.05)。两种植被覆盖下的土壤呼吸均呈现明显的季节变化规律,最大值均出现在8月9日,玉米土壤呼吸的季节变化振幅大于绿豆。统计分析表明,土壤温度是绿豆和玉米生态系统土壤呼吸动态变化的主要影响因子,van't Hoff模型和Arrhenius模型模拟的决定系数均超过0.73,土壤呼吸与土壤水分的相关关系不明显。绿豆和玉米土壤呼吸的温度敏感性指数Q10分别为3.31和2.16,Arrhenius模型模拟效果略优于van't Hoff模型,玉米土壤的活化能(79.41kJ·mol-1)大于绿豆土壤(55.72kJ·mol-1)。

The study of soil respiration under different crops is important to the carbon cycle research in the agro-eco- system. In this study, soil respiration of mung bean （ Vigna radiate L. ） field and maize （Zea mays L. ） field in hilly area of North China were measured during the growing period of July - October 2006 based on the IRGA technique. The diurnal and seasonal variations of soil respiration at two agro-eeosystems were analyzed. The results showed that the overall soil respiration rate of mung bean field was 2. lllxmol ~ m-2 ~ s-1, larger than 1. 901xmol ~ m 2 . s-l at maize field significantly. There were significant seasonal variations of soil respiration at two agro-ecosystems, and the amplitude changes in maize field was larger than in the mung bean field. The maximum respiration rates of maize and mung bean cropland both occurred at August 9. Statistic analysis showed soil temperature was the dominant environ- mental factor affecting the seasonal variation of soil respiration. Moreover, both the van＇t Hoff model and Arrhenius model satisfactorily described the soil respiration as a function of soil temperature at the two systems with R2 more than 0.73. No significant correlation between soil respiration and soil water content was found. The temperature sensitivity of soil respiration （Q10） was 3.31 and 2. 16 for the maize and mung bean field, respectively. The Arrhenius model present a better performance than the van＇t Hoff model, and the soil activation energy in the maize field （79.41 kJ tool- 1 ） was larger than in the mung bean field （55.72kJ tool-1 ）.