Prediction of effective rainfall, rainfall which contributes to the plant available water content, for lawns remains a challenge despite its critical role in accurately estimating a soil water balance and irrigation water requirement. The objective of this research was to validate simple runoff models for estimating effective rainfall on St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze ‘Raleigh’] turf managed under varying irrigation strategies. A field experiment was conducted at Texas A&M Urban Landscape Runoff Facility in College Station, TX, USA. Effective rainfall during the irrigation season was approximately 16% of measured rainfall but varied with rainfall depth and irrigation management. Methods which accounted for initial abstraction and subsequent rainfall independently were more accurate than simple coefficient models which only accounted for runoff as a percentage of daily rainfall depth. In general, St. Augustinegrass lawns can abstract 12.5 mm of water before rainfall becomes ineffective (runs off). These findings suggest accurate estimates of effective rainfall can be achieved using readily-available methods such as the SCS Curve Number model with adjustments for irrigation management strategy. Implementing more accurate effective rainfall estimates may reduce irrigation applied without decreasing turf quality.

中文翻译：

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不同灌溉计划下 St. Augustinegrass 草坪的有效降雨量估算

尽管草坪在准确估计土壤水平衡和灌溉用水需求方面发挥关键作用，但预测有效降雨量（降雨量有助于植物可用水含量）仍然是一个挑战。本研究的目的是验证用于估算圣奥古斯丁草[ Stenotaphrum secundatum] 的有效降雨量的简单径流模型(Walter) Kuntze 'Raleigh'] 草坪在不同的灌溉策略下进行管理。田间试验在美国德克萨斯州大学城的德克萨斯 A&M 城市景观径流设施中进行。灌溉季节的有效降雨量约为实测降雨量的 16%，但因降雨深度和灌溉管理而异。独立考虑初始取水和后续降雨的方法比仅考虑径流占日降雨深度百分比的简单系数模型更准确。一般来说，St. Augustinegrass 草坪可以在降雨变得无效（流失）之前抽取 12.5 毫米的水。这些研究结果表明，可以使用现成的方法（如 SCS 曲线数模型，并根据灌溉管理策略进行调整）来准确估计有效降雨量。实施更准确有效的降雨量估算可以减少灌溉量而不会降低草坪质量。