东非狼尾草入侵对冷季型草坪土壤呼吸及草坪质量的影响

Effects of Kikuyugrass invasion on soil respiration rate and quality of cool season turf

试验以草地早熟禾(Poa pretensis)、多年生黑麦草(Lolium perenne)和高羊茅(Festuca arundinacea)冷季型混播草坪为对象,研究了东非狼尾草(Pennisetum clandestinum)入侵后,土壤呼吸速率、草坪品质及地上生物量等方面的变化。结果表明,东非狼尾草入侵降低了混播草坪白天土壤呼吸速率、土壤温度及土壤含水量,改变了白天土壤呼吸曲线,但对最大呼吸强度(3.68μmol·m-2·s-1)没有显著影响。相关性分析表明,混播草坪的土壤呼吸速率与温度呈显著正相关,与土壤含水量呈负相关,不过土壤呼吸速率与温度的相关性因东非狼尾草入侵发生了改变。另外,东非狼尾草入侵后,地上生物量显著提高(P<0.05),相反,叶片叶绿素含量显著降低(P<0.05)。根据9分制评定结果,东非狼尾草入侵后,草坪颜色、草坪质地和草坪均匀性均有降低,导致草坪品质变劣。

Present study investigated the effect of Kikuyugrass invasion on soil respiration rate, turf quality and above-ground biomass of cool season turf which composed of Kentucky bluegrass, perennial ryegrass and tall fescue. Results showed that Kikuyugrass invasion reduced diurnal soil respiration rate, soil temperature and soil water content. Moreover, Kikuyugrass invasion also changed the soil respiration curve but showed no effect on maximal soil respiration rate （3.68 μmol·m-2·s-1）. Soil respiration rate showed a significant positive correlation with soil temperature, but negatively correlated with soil water content in cool-season turf without Kikuyugrass invasion. However, no significant correlation between soil respiration rate and temperature was found after Kikuyugrass invasion. In addition, Kikuyugrass invasion significantly increased turf above-ground biomass （P〈0.05） but decreased total leaf chlorophyll content （P〈0.05）. Kikuyugrass invasion led to poorer turf quality in terms of Nine Points System, e.g. color, texture, and surface uniformity were significantly decreased by Kikuyugrass invasion.