Kebede Nigusie, Ayana Mekonen, Mekonnen Boja
Department of Water Resources Engineering, Adama Science and Technology University Adama, Ethiopia.
Heliyon. 2025 Feb 8;11(4):e42566. doi: 10.1016/j.heliyon.2025.e42566. eCollection 2025 Feb 28.
In response to the growing challenge of water scarcity in agriculture, efficient irrigation planning and management have become increasingly essential. A critical component of this is determining the precise water requirements of crops. This study was conducted at Melkasa Agricultural Research Centre in Ethiopia during February to May in 2023 and 2024 and focused on quantifying the water requirement and crop coefficient of onion (Allium cepa L.), Nafis variety. Using weighable lysimeters, the study measured field-level water balance components, with crop evapotranspiration calculated through the water balance equation. The CROPWAT model and meteorological data from a station located nearby were used to estimate reference evapotranspiration. The results indicated that the pooled seasonal crop evapotranspiration was 460.27 mm, while the reference evapotranspiration for the same period was 509.18 mm. The average crop coefficient values were determined to be 0.68, 0.89, 1.03, and 0.86 for the initial, developmental, mid-, and late-season stages, respectively. Additionally, a third-order polynomial equation was established to predict the values of the crop coefficient based on the number of days after transplanting. These findings offer valuable insights for improving water resource use efficiency and optimizing irrigation scheduling for the production of onion, particularly in regions like Melkasa, where neither field-based measured data nor site-specific validated estimation methods are lacking.
为应对农业水资源短缺日益严峻的挑战，高效灌溉规划与管理变得愈发重要。其中的一个关键要素是确定作物的确切需水量。本研究于2023年2月至5月以及2024年2月至5月在埃塞俄比亚的梅尔卡萨农业研究中心开展，聚焦于量化纳菲斯品种洋葱（Allium cepa L.）的需水量和作物系数。该研究使用可称重蒸渗仪测量田间水平的水分平衡组成部分，并通过水分平衡方程计算作物蒸散量。利用CROPWAT模型和附近一个站点的气象数据来估算参考蒸散量。结果表明，合并后的季节性作物蒸散量为460.27毫米，而同期的参考蒸散量为509.18毫米。初始期、发育期、中期和后期的平均作物系数值分别确定为0.68、0.89、1.03和0.86。此外，还建立了一个三阶多项式方程，用于根据移栽后天数预测作物系数值。这些发现为提高水资源利用效率以及优化洋葱生产的灌溉调度提供了宝贵的见解，尤其是在梅尔卡萨这样既缺乏基于田间实测数据也缺乏针对特定地点的有效估算方法的地区。
