Abstract Heat waves are problematic for grazing livestock systems in regions dependant on temperate (cool-season) pasture species, owing to the often minimal heat tolerance (thermotolerance) of these pastures. A field experiment in north-west Tasmania, Australia, tested the hypothesis irrigating more frequently reduces detrimental heat wave effects on perennial ryegrass (Lolium perenne L.) above-ground growth and short-term persistence (measured via basal frequency). Heat wave conditions were imposed using freestanding infrared heater arrays fitted with a novel control system designed for evaluating heat wave mitigation options. The control system enabled the extent of warming to be regulated, whilst applying an equal infrared flux (heating) to all heated plots. Increasing the frequency of irrigation events suppressed crown temperature (plant-soil interface) elevation under heaters. When irrigation was applied every 2, 5 or 10 days, median crown temperature elevation under heaters equalled 5.5 °C, 6.5 °C and 7.0 °C, respectively. However, detrimental effects of imposed heat wave conditions on perennial ryegrass growth were not mitigated by more frequent irrigation events. This resulted from the small differences in crown temperature elevation between irrigation frequency treatments, combined with supraoptimal crown temperatures occurring

中文翻译：

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更频繁地灌溉能否减轻热浪对多年生黑麦草生长和持久性的不利影响？

摘要 由于这些牧场的耐热性（耐热性）通常最低，因此热浪对于依赖温带（冷季）牧草物种的地区的放牧牲畜系统是有问题的。在澳大利亚塔斯马尼亚西北部进行的一项田间试验检验了更频繁地灌溉可以减少对多年生黑麦草 (Lolium perenne L.) 地上生长和短期持久性（通过基础频率测量）的有害热浪影响的假设。热浪条件是使用独立的红外加热器阵列施加的，该阵列配备了一种新颖的控制系统，旨在评估热浪缓解选项。控制系统能够调节升温的程度，同时对所有加热的地块施加相等的红外通量（加热）。增加灌溉事件的频率抑制了加热器下的冠部温度（植物-土壤界面）升高。当每 2、5 或 10 天灌溉一次时，加热器下的平均冠温升高分别等于 5.5 °C、6.5 °C 和 7.0 °C。然而，更频繁的灌溉事件并没有减轻强加的热浪条件对多年生黑麦草生长的不利影响。这是由于灌溉频率处理之间树冠温度升高的微小差异，再加上发生的超最佳树冠温度 更频繁的灌溉事件并没有减轻强加的热浪条件对多年生黑麦草生长的不利影响。这是由于灌溉频率处理之间树冠温度升高的微小差异，再加上发生的超最佳树冠温度 更频繁的灌溉事件并没有减轻强加的热浪条件对多年生黑麦草生长的不利影响。这是由于灌溉频率处理之间树冠温度升高的微小差异，再加上发生的超最佳树冠温度