Urban lawns comprise a significant portion of urban greenery and provide several ecosystem services. Nevertheless, maintaining lawns comes with significant water costs in semi-arid inland southern California, as they require consistent irrigation to stay healthy and productive. The main objective of this study was to evaluate the effect of a wide range of irrigation rates and frequencies applied autonomously by a smart ET-based controller on the aesthetic value, cooling potential, and CO2 efflux of two warm-season turfgrass species. For three years, we studied the responses of Buffalograss and St. Augustinegrass to six irrigation rates and two irrigation frequencies in Riverside, California. Under historical average climate conditions, the minimum irrigation rate for Buffalograss was 93 % ETo, and for St. Augustinegrass, it was 74 % ETo. Under projected future climate conditions, the estimated minimum irrigation rate for Buffalograss did not change, but for St. Augustinegrass, it increased by 4 % and 7 % in 2100 under low emission (RCP 4.5) and high emission (RCP 8.5) scenarios, respectively. On average, canopy minus air temperature in Buffalograss was 6.2 ℃, and in St. Augustinegrass, it was 1.1 ℃. The average CO2 efflux in Buffalograss was 122.3 µg CO2-C m−2 s−1, and in St. Augustinegrass, it was 182.8 µg CO2-C m−2 s−1. Our results showed that turfgrass aesthetic values, cooling potential, and CO2 efflux diminished as the irrigation rate decreased, but at different rates for each turfgrass species.

中文翻译：

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评估圣奥古斯丁草和水牛草的节水、美学价值、蒸发冷却和 CO2 排放之间的权衡


城市草坪构成了城市绿化的很大一部分，并提供多种生态系统服务。然而，在南加州半干旱的内陆地区，维护草坪需要大量的水费，因为它们需要持续的灌溉才能保持健康和生产力。本研究的主要目的是评估由基于 ET 的智能控制器自主应用的各种灌溉速率和频率对两种暖季草坪草物种的美学价值、冷却潜力和 CO2 外排的影响。三年来，我们研究了加利福尼亚州里弗赛德市水牛草和圣奥古斯丁草对 6 种灌溉速率和 2 种灌溉频率的响应。在历史平均气候条件下，水牛草的最低灌溉量为 93 % ETo，圣奥古斯丁草的最低灌溉量为 74 % ETo。在预测的未来气候条件下，水牛草的估计最低灌溉量没有变化，但在低排放 （RCP 4.5） 和高排放 （RCP 8.5） 情景下，圣奥古斯丁草的最低灌溉量在 2100 年分别增加了 4% 和 7%。平均而言，水牛草的冠层减去空气温度为 6.2 °C，而圣奥古斯丁草为 1.1 °C。水牛草中的平均 CO2 外排量为 122.3 μg CO2-C m-2 s-1，而圣奥古斯丁草中为 182.8 μg CO2-C m-2 s-1。我们的结果表明，随着灌溉速率的降低，草坪草的审美价值、冷却潜力和 CO2 外排减少，但每种草坪草物种的速率不同。