春玉米灌浆成熟期土壤呼吸动态变化及其影响因素

The Dynamics of Soil CO_2 Efflux and Its Controlled Factors in Maize Filed from Grain Filling to Mature Stage

以北京郊区春玉米为研究对象,采用LI-8150土壤CO2通量连续测定系统研究玉米灌浆—成熟期的土壤呼吸速率。研究表明,土壤呼吸速率在晴天呈变化幅度较大的单峰型曲线,最大值4.43μmol m2/s;阴天呈变化幅度较平缓的单峰型曲线,最大值2.90μmol m2/s;雨天土壤呼吸速率为震荡曲线,最大值2.48μmol m2/s,最小值0.41μmol m2/s。土壤呼吸速率的日际变化规律为连续的"单峰型"曲线。土壤呼吸速率与土壤温度呈指数关系,与土壤含水率呈幂函数关系,土壤温度和含水率综合因素与土壤呼吸速率函数为指数形式,相关性较显著。

In this study,LI-8150 long-term chamber was used to monitor continuously soil CO2 efflux rate in spring maize farmland from the grain-filling to mature stage.The results were as follows： there was an obvious daily dynamic change of soil respiration in the maize farmland ecosystem under different kinds of weather condition,it was a single peak curve at the sunny and cloudy day,and the maximum was 4.43 μmol m2/s and 2.90 μmol m2/s,while it was a shocked curve at the rainy day,where the maximum was 2.48 μmol m2/s and the minimum was 0.41 μmol m2/s.On the other hand,soil respiration showed a continuous peaked curve day by day;it also showed a remarkable positive correlation with soil temperature and soil water content.Finally,equations were fitted among soil respiration,soil temperature and soil water content at three typical weather conditions and during experiment period,the relationships of which were significant.