Analysis of Spring Barley Actual Evapotranspiration

0426785 - ÚVGZ 2014 RIV CZ eng K - Conference Paper (Czech conference)
Pozníková, Gabriela - Fischer, Milan - Pohanková, Eva - Žalud, Zdeněk - Trnka, Miroslav
Analysis of Spring Barley Actual Evapotranspiration.
MendelNet 2013: Proceedings of International PhD Students Conference. Brno: Mendel university, 2013 - (Škarpa, P.; Ryant, P.; Cerkal, R.; Polák, O.; Kovárník, J.), s. 357-361. ISBN 978-80-7375-908-7.
[MendelNet 2013. Mendelova univerzita v Brně (CZ), 20.11.2013-21.11.2013]
R&D Projects: GA MŠMT(CZ) EE2.3.20.0248; GA MZe QJ1310123
Institutional support: RVO:67179843
Keywords : reference evapotranspiration * Bowen ratio/energy balance method * crop coefficient * spring barley * Czech Republic
Subject RIV: EH - Ecology, Behaviour

Evapotranspiration (ET) represents the main water-loss part of the water balance in agricultural landscape. The reliable quantification of the agricultural field ET is, however, still a challenge. To calculate ET, the Bowen ratio/energy balance (BREB) method was used in this study. It is based on measurements of the temperature and humidity gradients and radiation balance with the soil heat flux. Calculated ET was further used to quantify crop coefficient (Kc). Subsequently, we analysed the crop coefficient of spring barley during one growing season since 7th May 2013 to 30th July 2013. We used the data obtained above 1-ha spring barley field in Bystřice nad Pernštejnem, Czech Republic. In particular, we investigated how Kc correlates to climatic conditions as rainfall and soil humidity and how it reflects Plant Area Index (PAI) during the year during different parts of growing season. The cumulative ET of spring barley was 228.6 mm per investigated period. For reference evapotranspiration (ETo) two different approaches were used. Typically, a reference grass cover 0.12 m high standard for Europe. On the other hand, in the USA it is common to use also alfalfa (0.50 m high). ETo of grass was 296.3 mm and ETo of alfalfa was 351.4 mm. Maximum Plant Area Index occurred in June and its value was 4.1. Mean Kc in May was 1.17 for reference grass and 1.03 for alfalfa. Similarly in June, Kc was equal to 1.16 (grass) and 1.03 (alfalfa). Finally in July, for reference grass Kc was 0.55 and 0.48 for alfalfa. The decline at the end of the growing season was caused by dry weather and ripe stage of spring barley.
Permanent Link: http://hdl.handle.net/11104/0232526