新疆棉田小区域碳变化量研究

Study on Carbon Variation in Small Areas of Cotton Fields in Xinjiang

为研究膜下滴灌条件下棉田小区域碳变化量,在棉花生长期内采用Li-8100A土壤碳通量自动测定仪和LCpro+光合仪连续观测不同样地土壤呼吸速率和净光合速率。结果表明:不同样地的土壤呼吸速率日变化均表现为单峰型曲线,峰值出现在16:00;而棉田净光合速率日变化则表现为单双峰曲线交替变化规律。两者月变化均呈现先升高后降低的趋势,7月土壤呼吸速率和净光合速率达到最大值。不同样地间土壤呼吸速率和净光合速率存在差异,土壤呼吸速率表现为垄间>垄上>裸地,净光合速率表现为垄间>垄上。棉田小区域在棉花整个生育期内均表现为碳汇,6-9月棉田净固碳总量为2 203.7 C g/m^2,光合作用固碳量为土壤呼吸排碳量的2.67倍。

In order to study the carbon variation in cotton field under drip irrigation, the soil respiration rate and net photosynthetic rate were observed continuously during the cotton growth period using Li-8100 A soil carbon flux automatic analyzer and LCpro+ photosynthetic apparatus. The results showed that the diurnal variation of soil respiration rates showed a unimodal curve with the peak at 16:00, while the diurnal variation of net photosynthetic rates in cotton field showed an alternating pattern of unimodal and bimodal curves. Both months showed a trend of increasing first and then decreasing, and the soil respiration rates and net photosynthetic rates reached the maximum in July. There were differences in soil respiration rates and net photosynthetic rates between different regions. The soil respiration rates were as follows inter-ridges > ridges > bare land, and the net photosynthetic rates was inter-ridges > ridges. The small area of cotton field showed carbon sinks throughout the growth period. From June to September, the total net carbon fixation in cotton fields was 2 203.7 C g/m^2, and the carbon sequestration by photosynthesis was 2.67 times that of soil respiration.