Soil and Water Research - In Press
The role of ground heat flux in estimating evapotranspiration by the Penman-Monteith method on mountain meadowOriginal Paper
Michal Dohnal, Jana Votrubová, Rebeka Mazúchová, Miroslav Tesař
Ground heat flux (G) is often overlooked component of the surface energy balance, and its accurate determination remains challenging. In the present study, the accuracy of various G estimation methods is examined using long-term measurements from the Central European mountain meadow. The impact of different G approximation on calculated evapotranspiration by the Penman-Monteith method (ET) is analyzed. Soil heat flux measurements and surface temperature data were used to determine G, while net radiation was used to approximate G. Neglecting G led to an overestimation of ET in daily timestep. On the contrary, the FAO-recommended hourly approximation overestimated G, underestimating ET. Site-specific calibrations of G prediction models improved their accuracy. For daily average G, as well as for hourly average G, simple constant parameter models (i.e., models including single parameter specifying fraction of net radiation directly) provide satisfactory accuracy of ET evaluation. However, in hourly timestep, net radiation fails as a predictor of G shortly after sunrise and before sunset. The findings emphasize the importance of considering G in ET calculations and the need for site-specific calibrations of G estimation models.
Determination of soil loss on agricultural land based on field measurements in the Czech RepublicOriginal Paper
Jiří Kapička, Věra Kolbabová, Miroslav Bauer, Tomáš Dostál, Petr Kavka, Josef Krása, Alla Achasova
The current erosion protection set up in the Czech Republic (CZ) is based on the long-term soil loss due to water erosion using the USLE equation. The range of recommended values of tolerable soil loss by water varies among different authors and approaches, depending on the specific area and its parameters. It is, therefore, important to ask the following questions. What is the real range of soil loss by water erosion in CZ. To determine the range of soil loss, a model extrapolation was carried out. The model extrapolation was based on the results from two main experimental measurements. Both from evaluated volume soil loss of real erosion events and field experiments based on measurements of erosion induced by artificial rainfall. The results of modelled extrapolation of the range of long-term soil loss are in the range 6.9 – 13.8 t/ha per year.