Towards Accurate Estimation of Crop Water Requirement without the Crop Coefficient Kc: New Approach Using Modern Technologies

Modern technologies to measure actual evapotranspiration, ETa, were implemented at an experimental farm near Bologna, Italy. Large-aperture scintillometer and eddy covariance instruments were installed. The results showed significant differences between actual evapotranspiration measured by eddy cov...

Full description

Saved in:
Bibliographic Details
Published in:Irrigation and drainage 2017-10, Vol.66 (4), p.469
Main Authors: Ragab, R, Evans, JG, Battilani, A, Solimando, D
Format: Article
Language:English
Subjects:
Atmospheric water
Cell culture
Coefficients
Copyright
Covariance
Crops
Cultures
Evapotranspiration
Experimental farms
Instruments
Irrigation
Irrigation water
Mathematical models
Meteorological data
Vortices
Water
Water demand
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Modern technologies to measure actual evapotranspiration, ETa, were implemented at an experimental farm near Bologna, Italy. Large-aperture scintillometer and eddy covariance instruments were installed. The results showed significant differences between actual evapotranspiration measured by eddy covariance and scintillometer when compared with the potential reference evapotranspiration, ET0, calculated from meteorological data using the Penman-Monteith equation and the crop potential evapotranspiration, ETc, which is based on the ET0 and the crop coefficient, Kc. The ETc and ET0 showed higher values than those of ETa obtained by eddy covariance and scintillometer. On average the actual evapotranspiration measured by eddy covariance and scintillometer for the cropping seasons 2014 and 2015 represented 45 and 35% of the ET0 or the ETc, respectively. The ET0, or the ETc, represent the atmospheric water demand while, fundamentally, the crop water requirement should be based on crop water demand better represented by the actual evapotranspiration. At present, the results indicate that the actual crop water requirement based on modern technologies could save at least 50% of irrigation water for this region. Another benefit is that these modern technologies do not need the crop coefficient Kc, which for many irrigation practitioners is difficult to obtain. Copyright © 2017 John Wiley & Sons, Ltd. Résumé Les technologies modernes pour mesurer l'évapotranspiration réelle, ETa, ont été mises en place dans une ferme expérimentale près de Bologne (Italie), à savoir: scintillomètre à large ouverture et mesure des fluctuations turbulentes (eddy covariance). Les résultats ont montré des différences significatives entre l'évapotranspiration réelle mesurée par eddy covariance et par scintillométrie d'une part, par rapport à l'évapotranspiration potentielle de référence, ET0, d'autre part. Cette dernière est calculée à partir de données météorologiques en utilisant l'équation de Penman-Monteith et l'évapotranspiration potentielle de la culture, ETc, qui est basée sur ET0 et le coefficient cultural, Kc. ETc et ET0 ont montré des valeurs plus élevées que celles de ETa obtenues par eddy covariance et scintillométrie. En moyenne, l'évapotranspiration réelle mesurée par eddy covariance et scintillométrie pour les saisons de cultures 2014 et 2015 représentait 45 et 35% de ET0 ou de ETc respectivement. ET0, ou ETc, représentent la demande d'eau atmosphérique alors que, fondamental
ISSN:1531-0353
1531-0361
DOI:10.1002/ird.2153