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Article

High-Frequency Stable-Isotope Measurements of Evapotranspiration Partitioning in a Maize Field

1
Centre for Water Resource Systems, TU Wien, Karlsplatz 13, 1040 Vienna, Austria
2
Institute of Hydraulic Engineering and Water Resources Management, TU Wien, Karlsplatz 13/222, 1040 Vienna, Austria
3
Soil and Water Management and Crop Nutrition Subprogramme, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency (IAEA), 1400 Vienna, Austria
4
Institute for Land and Water Management Research, Federal Agency for Water Management, Pollnbergstrasse 1, 3252 Petzenkirchen, Austria
*
Author to whom correspondence should be addressed.
Water 2020, 12(11), 3048; https://doi.org/10.3390/w12113048
Received: 13 September 2020 / Revised: 20 October 2020 / Accepted: 28 October 2020 / Published: 30 October 2020
(This article belongs to the Section Water, Agriculture and Aquaculture)
Knowledge of the evaporation (E) and transpiration (T) components of evapotranspiration (ET) is important for ecohydrological modeling and agricultural productivity. The stable-isotope method offers the possibility to partition E and T due to the distinct differences in the isotopic signals of the sources. In this study, the concentration and isotopic ratios for oxygen-18 (18O) of water vapor in the ecosystem boundary layer of a growing maize field at the Hydrological Open Air Laboratory (HOAL) catchment in Austria were measured using a high-frequency field-sampling device. In conjunction with isotope samples from the soil and maize plants, these data were used to partition ET using the Keeling plot technique. Eddy covariance and sap flow measurements were used to provide a comparison to test the stable-isotope method. The fraction of transpiration (Ft) calculated with the stable-isotope method showed good agreement with the sap flow method. Overall daily average values of Ft were in a range from 43.0 to 88.5% with T accounting for an average value of 67.5% of the evapotranspiration over the nine days of the experimental period. Following a precipitation event of 9.7 mm, Ft increased from 63.4 to 88.5% over the next four days as the upper layer of the soil dried out while the plants accessed deeper soil water. View Full-Text
Keywords: evapotranspiration; stable isotopes; Keeling plot evapotranspiration; stable isotopes; Keeling plot
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MDPI and ACS Style

Hogan, P.; Parajka, J.; Oismüller, M.; Heng, L.; Strauss, P.; Blöschl, G. High-Frequency Stable-Isotope Measurements of Evapotranspiration Partitioning in a Maize Field. Water 2020, 12, 3048. https://doi.org/10.3390/w12113048

AMA Style

Hogan P, Parajka J, Oismüller M, Heng L, Strauss P, Blöschl G. High-Frequency Stable-Isotope Measurements of Evapotranspiration Partitioning in a Maize Field. Water. 2020; 12(11):3048. https://doi.org/10.3390/w12113048

Chicago/Turabian Style

Hogan, Patrick, Juraj Parajka, Markus Oismüller, Lee Heng, Peter Strauss, and Günter Blöschl. 2020. "High-Frequency Stable-Isotope Measurements of Evapotranspiration Partitioning in a Maize Field" Water 12, no. 11: 3048. https://doi.org/10.3390/w12113048

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