土壤温度和水分对不同类型沙丘土壤呼吸的影响

通过实验室土壤培养试验,测定了不同土壤温度(8,18,28,38℃)和含水量对科尔沁退化沙质草地不同生境(流动沙丘,半固定沙丘和固定沙丘)土壤呼吸的影响。结果表明,在8~38℃范围内,土壤呼吸速率与温度呈正相关。在含水量为田间持水量(WFC)的5%~65%范围内,3种类型的土壤呼吸速率随含水量的增加而升高,当超过该范围时,流动沙丘的土壤呼吸速率仍呈上升趋势,而38℃培养条件下的半固定沙丘和18~38℃下的固定沙丘的土壤呼吸速率呈下降趋势。土壤温度和水分对土壤呼吸作用存在明显的交互效应,不同类型沙化土壤呼吸作用强弱存在显著差异。温度系数Q10值随含水量的变化为:流动沙丘1.90~2.15,半固定沙丘1.80~2.13,固定沙丘1.82~2.16。

Effects of Soil Temperature and Moisture on Soil Respiration in Different Sand Dune Types

The effects of soil temperatures(8,18,28,38℃) and water content on soil respiration in three different sandy habitats(shifting,semi-fixed and fixed sand dune) inHorqinsandy land were evaluated using a laboratory soil incubation experiment.The results indicated that soil respiration rate was positively correlated to soil temperature from 8 to 38℃ and it increased with water content from 5 to 65 percent of water field capacity(WFC) in three soil types.Whenwater content was over the range,soil respiration rate in shifting sand dune increased continually,whereas it decreased at 38℃in semi-fixed and at 18～38℃in fixed sand dune.The results suggested the interactive effects of temperature and water content on soil respiration.There were significant differences in soil respiration among the varioussand dune types.The temperature coefficient Q_(10)varied from 1.90 to 2.15 in shifting sand dune,1.80 to 2.13 in semi-fixed sand dune and 1.82 to 2.16 in fixed sand dune,according to water content variation.