黄土丘陵区白羊草与达乌里胡枝子混播草地土壤呼吸日变化特征

Diurnal variations of soil respiration in Bothriochloa ischaemum and Lespedeza davurica mixture pasture at Loess Hilly Region

土壤呼吸是反映土壤质量和肥力性状的重要指标,阐明禾―豆混播草地土壤呼吸作用的变化规律及其影响因素,可以为准确评估混播草地的环境效应及响应提供依据。在2011和2012年6月份,采用动态密闭气室分析法,比较了白羊草(Bothriochloa ischaemum)与达乌里胡枝子(Lespedeza davurica)不同比例间作混播草地总土壤呼吸速率的日变化特征、混播植物贡献率以及温度敏感性等。结果表明,不同混播比例草地的总土壤呼吸速率日变化为单峰型曲线,峰值出现在12:00~14:00。总土壤呼吸速率日均值高低顺序为单播白羊草】白羊草和达乌里胡枝子间作】单播达乌里胡枝子。不同间作比例草地的总土壤呼吸速率与白昼气温相关显著(P【0.05),而与5、10和15 cm土层白昼土壤温度关系不明显;单播条件下,白羊草草丛的土壤呼吸对温度的敏感性高于达乌里胡枝子;各草地土壤呼吸Q10值的变化范围为1.48~2.61,以单播白羊草最高,单播达乌里胡枝子和两者间作混播草地间无显著差异(P】0.05)。

Soil respiration is an important index for evaluation of soil quality and fertility properties.The clarification of the variations and influence factors of soil respiration in grass-legume mixture pasture will provide evidence for accurately assessment of the effects and response of mixture pasture.In order to comprehensively evaluate the performance of mixture pasture of Bothriochloa ischaemum and Lespedeza davurica,diurnal changes of total soil respiration rate with different mixture ratio of the two species,the contribution of each species and temperature responses of each species were investigated and analyzed in June,2011 and 2012.The diurnal variation of total soil respiration rates were asymmetric unimodal curves which peaked between 12:00 and 14:00.The daily average of total soil respiration rate decreased in the following order:B.ischaemum monoculture > B.ischaemum and L.davurica intercropping > L.davurica monoculture.There were significant correlations between total soil respiration rate and air temperature(P < 0.05),while there was no significant correlations between soil respiration rate and soil temperature at 5,10 or 15 cm soil layers.In monoculture,soil respiration rate of B.ischaemum was more sensitive to temperature than that of L.davurica.Q10 values ranged from 1.48 to 2.61 with the highest Q10 value of B.ischaemum monoculture.There was no significant differences between L.davurica monoculture and mixtures.