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

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 degrees C, while that of cultivated marsh was 15.80 +/- 3.41 degrees C. The soil respiration rate of uncultivated marsh in August and September was 156.41 +/- 76.91 mg x m(-2) x h(-1) and 116.75 +/- 57.43 mg x m(-2) x 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.