沼泽湿地垦殖前后土壤温度变化及其对土壤热状况的影响

Variation of soil temperature before and after cultivation of marsh and its effect on soil thermal regime.

沼泽湿地具有重要的生态与环境功能,其对全球气候变化较为敏感,土壤温度变化能够很好地指示气候的波动.沼泽湿地土壤温度呈明显的“正弦曲线”型年、季动态,不同深度土壤年均温度呈“U”型特征.5～9月份沼泽湿地10cm土壤平均温度为1169±304℃,垦殖后农田土壤为1580±341℃沼泽湿地土壤8、9月份土壤呼吸分别为15641±7691mg·m-2·h-1和11675±5743m-2·h-1,是同时期农田土壤呼吸通量的146%和131%,土壤温度与土壤呼吸通量呈显著正相关关系.

Marsh has important ecological and environmental functions and is sensitive to the global climate change,while the variation of soil temperature could better indicate the climate fluctuation.Our study showed that the annual and seasonal dynamic changes of soil temperature in marsh showed distinctly “sinusoid' character curve,whereas the mean annual temperature of different soil depths showed “U' feature.From May to September,the mean temperature at the topsoil (10 cm) of uncultivated marsh was 11.69±3.04℃,while that of cultivated marsh was 15.80±3.41 ℃.The soil respiration rate of uncultivated marsh in August and September was 156.41±76.91 mg·m^-2 ·h^-1 and 116.75±57.43 mg·m^-2 ·h^-1 ,accounted for 14.6% and 13.1 % of that of cultivated marsh,respectively.The soil temperature was significantly positively correlated with soil respiration.