修剪高度对草地早熟禾草坪生态效益的影响

Effects of trimming height on ecological benefits of bluegrass turf

以生长4年的草地早熟禾(Poa pratensis)草坪为供试材料,设置12、8、5、3 cm 4个留茬高度,以不修剪(自然高度约18 cm)作为对照,于2019年8-10月通过测试草坪的固碳、释氧、释水、吸热和降温等5个生态因子指标,运用隶属函数分析法对其生态效益进行综合评价,以探讨半干旱地区休闲草坪的合理修剪高度。结果表明:草地早熟禾草坪上述5个生态因子的生态效能均随其修剪高度的降低而减少,按照生态效益综合评价三级制考量,不修剪对照生态效益最高,为Ⅰ级,修剪高度12 cm处理和8 cm处理生态效益较高,为Ⅱ级,修剪高度5 cm处理和3 cm处理生态效益最低,为Ⅲ级。为兼顾各修剪高度草坪的景观效果和生态效益,以及景观维持时长,建议干旱、半干旱地区城市休闲草坪的合理修剪高度以8~12 cm为宜。

Kentucky bluegrass(Poa pratensis)turf,which had been growing for 4 years at the south campus of Inner Mongolia Agricultural University,Hohhot,was mowed at four different heights(12,8,5 and 3 cm)with non-trimmed plants(relative height 18 cm)as the control.Five ecological parameters including carbon fixation,oxygen release,water release,heat absorption and cooling of lawn were measured between Aug.and Oct.2019.Ecological benefits were comprehensively evaluated by the method of membership function analysis to investigate the optimum mowing height of leisure lawn in semi-arid areas.The results showed that the ecological efficiency of the five parameters decreased with the decrease in mowing height.According to the three-level system of comprehensive evaluation of ecological benefits,the unpruned control had the highest ecological benefit as Level I,followed by the trimming height at 12 cm and 8 cm as Level II,while the trimming height at 5cm and 3cm had the lowest ecological benefit as Level III.Considering the landscape effects,ecological benefits and the duration of landscape maintenance,our results suggested that the optimum mowing height of urban leisure lawn should be 8~12 cm.