摘要
根据农田实测资料 ,分析二氧化碳浓度时空分布规律 ,研究二氧化碳浓度降低对作物群体光合生产力的影响。主要结果 :1.白天 ,由于小麦光合作用 ,群体内部二氧化碳浓度降低。在空气动力作用下二氧化碳由大气和土壤表面向冠层内输送 ,冠层中通量为零处浓度最低。小麦各生育期里 ,二氧化碳浓度低值出现高度均与叶面积密度分布最大位置相一致。 2 .晴天 ,由小麦冠层剖面二氧化碳浓度等值线图看出 :一般 9～ 18时有一个低值区 ,中心高度约在 1/ 2株高处 ,浓度较冠顶以上 1m处约低 2 0～ 4 0 μL/ L,在风速小、辐射强的天气条件下二氧化碳浓度更低。另外 ,从等值线图还可看出 ,由于土壤中二氧化碳浓度很高 。
The distribution of CO 2 concentration and the effects of its reduction on wheat photosynthesis were analyzed using field-measured data. Following results were obtained: (1) In the daytime, CO 2 concentration was reduced in wheat field as a result of photosynthesis. The carbon dioxide from the atmosphere and soil surface was moved into the crop canopy and the lowest CO 2 concentration occurred where CO 2 flux was zero. During various developmental stages of wheat crop the lowest CO 2 concentration was always found in the segments of the plants with highest leaf area. (2) As shown by the CO 2 concentration isoplethic figures, there was a low concentration area between 9:00 and 18:00 on clear days (being 20～40μL/L lower than that measured 1 m above the crop canopy), and the center of which was located at 1/2 plant height. In this area, CO 2 concentration could be further reduced under conditions of weak wind and strong solar radiation. In addition, the gradients of CO 2 concentration near the ground level were steeper than in upper positions, which was produced by the CO 2 released from the soil.
出处
《中国农业气象》
CSCD
北大核心
1996年第6期24-29,共6页
Chinese Journal of Agrometeorology
基金
国家自然科学基金资助项目
