科尔沁沙地玉米(Zea mays)田垄上和垄间土壤呼吸比较

采用动态密闭气室法测定分析了科尔沁沙地典型玉米(Zea mays)农田垄上和垄间土壤呼吸速率的差异及自养和异养呼吸特征,并估算了生态系统碳平衡。结果表明:(1)垄上和垄间土壤呼吸速率存在极显著差异(p0.001),且存在线性关系(p0.05);季节水平上垄上土壤呼吸可解释垄间土壤呼吸98.4%的变异。(2)季节水平上土壤总呼吸(RS)、异养呼吸(RH)和自养呼吸(RA)的温度敏感性指数Q10大小顺序为:RA(4.35)RS(3.10)RH(2.08)。(3)RS和RH之间存在显著差异,RA与RS和RH之间不存在显著差异;RA占RS比例的季节变化范围为28.1%~71.1%,生长季RH和RA占RS的比例均值分别为44.4%和55.6%。(4)科尔沁沙地典型农田生态系统在生长季为碳汇,可净固存大气CO2-C的量为659.1g·m-2。

Comparison of Soil Respiration Rate between Row and Inter-row of Maize (Zea mays) Field in the Horqin Sandy Land

Using an infrared gas analysis method (IRGA) CO₂ analyzer (Li-6400,USA), the present study explored the differences of soil respiration rate between row and inter-rows and the characteristics of the autotrophic and heterotrophic respiration at maize (Zea mays ) fields of Horqin Sandy Land, and then estimated the carbon balance of ecosystem. Results showed that: (1) There was significant difference of soil respiration rate between row and inter-rows (p<0.001), and there was a linear relationship between them (p<0.05); Approximately 98.4% (R²=0.984) variations in soil respiration of inter-rows could be explained by that of row. (2) The Q₁₀ values for R_S, R_H, and R_A were 4.35, 3.10 and 2.08, respectively. (3) There was a significant difference between R_S and R_H, but there was no significant difference between R_A and R_S as well as R_A and R_H. The proportion of R_A to total soil CO₂ emission ranged from 28.1% to 71.1% during the growing season, and the average proportion of R_H and R_A to R_S were 44.4% and 55.6%, respectively. (4) Maize field of Horqin Sandy Land was a carbon sink in the growth period, which could sequester carbon up to 659.1 gC·m^-2.