岩茶生长季节土壤呼吸日变化特征研究

Respiration diurnal variation characteristics of rock tea soil in growing season

于2014年3~5月通过室外定位观测10年生岩茶生长季节土壤呼吸速率从8：00到18：00的动态变化,探讨了岩茶土壤呼吸速率与土壤温度、土壤湿度的相关性。结果表明：岩茶3~5月生长季节土壤呼吸速率的变化范围为0.63~3.56μmol CO2/m^2·s,土壤呼吸的温度敏感性指数Q10在1.74~2.52之间。岩茶土壤呼吸速率的日变化趋势为单峰曲线,最大值出现在14：00,最小值出现在8：00,土壤呼吸速率在4、5月明显增大。茶园土壤呼吸速率与不同深度的土壤温度呈显著的指数关系,且10~15 cm深度的土壤温度对土壤呼吸速率的影响最为显著。Q10与土壤温度呈负相关,在3月及较深土层较大。土壤含水量与土壤呼吸速率间的相关性不显著。

Soil respiration rates as well as soil temperature and moisture at a 10-year-old rock tea plantation were measured from March to May in 2014, and soil respiration response to soil temperature and soil water content at different soil depths was discussed. The results showed that soil respiration rate varied from 0.63 to 3.56 μmol CO2/m^2·s, and the Q10 value ranged from 1.74 to 2.52 in growing season. Soil respiration rate exhibited a unimodal curve during 08：00-18：00with a maximum during 14：00 and a minimum during 8：00. Soil respiration rate increased with the soil temperature increasing, so soil respiration rate was significantly higher in April and May than that in March. With the exponential model, there was a positive, exponential relationship between soil respiration rate and soil temperature at different soil depths, and the soil temperature in 10-15 cm soil depth had the greatest effect on soil respiration rate. The Q10 value was negatively related to soil temperature at different depths and the Q10 value was the largest in March or at 10-15 cm soil depth. Soil respiration rate had no significant correlation with soil water content in different soil depths at the sites.