Study of Evapotranspiration and Crop Coefficients in Sweet Corn Fields
Other Title
食用玉米田區之蒸發散量及作物係數研究
Journal
台灣農業研究
Journal Volume
75
Journal Issue
3
Start Page
435
End Page
450
ISSN
2790-086X
Date Issued
2026-09-06
Author(s)
Abstract
Efficient irrigation management is essential for optimizing water use and maintaining crop productivity, particularly in regions such as Taiwan where rainfall distribution is uneven in both time and space. This study aimed to quantify crop evapotranspiration (ETc) and develop local crop coefficient (Kc) parameters for sweet corn using the eddy covariance system, and to validate irrigation scheduling based on these parameters using the Food and Agriculture Organization of the United Nations (FAO) CROPWAT 8.0 model. The total seasonal ETc values were 141.6 mm, 246.4 mm, and 199.9 mm for the autumn 2022, spring 2023, and autumn 2023 cropping seasons, respectively. Kc values also varied by growth stage, averaging 0.59 and 0.84 for the initial and mid-growth stages. A field validation trial was conducted to compare conventional irrigation with CROPWAT-derived irrigation scheduling. In the spring, yields did not differ significantly between treatments, whereas in the autumn, yields under conventional irrigation were significantly higher than those under the CROPWAT-based treatment. These results suggest that CROPWAT with established Kc values may not be suitable for estimating irrigation amounts during autumn cropping owing to greater variability in Kc values. However, it remains a promising tool for irrigation scheduling in spring cropping when local parameters are applied, suggesting that the fundamental water-requirement information established during the spring season might serve as a useful reference for irrigation decision-making.
臺灣降雨在時間與空間上的分布不均，因此高效的灌溉管理對於水資源利用及維持作物生產力至關重要。本研究旨在利用水汽通量儀 (eddy covariance system) 量化食用玉米之作物蒸發散量 (crop evapotranspiration; ETc)，並建立在地化之作物係數 (crop coefficients; Kc) 參數，同時利用聯合國糧食及農業組織 (Food and Agriculture Organization of the United Nations; FAO) CROPWAT 8.0 模式驗證基於上述參數之灌溉排程。研究結果顯示，2022 年秋作、2023 年春作及 2023 年秋作之全期作物蒸發散量分別為 141.6 mm、 246.4 mm 及 199.9 mm。作物係數值亦隨生育階段而異，生育初期與生育中期之平均值分別為 0.59 與 0.84。田間驗證試驗比較了慣行灌溉與基於 CROPWAT 推算之灌溉排程。結果顯示，春作期間在兩處理間之產量無顯著差異；然而於秋作期間，慣行灌溉處理之產量顯著高於 CROPWAT 基礎需水量處理。此結果顯示，由於秋作期間作物係數變異性較大，應用已建立之作物係數配合 CROPWAT 估算灌溉量可能較不適用於秋作。然而，該模式仍為春作灌溉排程之潛力工具。由春作所建立之基礎需水量資訊，可作為灌溉決策之重要參考依據。
Subjects
Eddy covariance system
CROPWAT 8.0
Irrigation scheduling
Evapotranspiration
水汽通量儀
灌溉排程
蒸發散量
Publisher
農業部農業試驗所
Type
journal article
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