Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1002/hyp.14077
Lizenz creative commons licence
Titel (primär) Estimating water balance components in irrigated agriculture using a combined approach of soil moisture and energy balance monitoring, and numerical modeling
Autor Schulz, S.; Becker, R.; Richard‐Cerda, J.C.; Usman, M.; aus der Beek, T.; Merz, R.; Schüth, C.
Quelle Hydrological Processes
Erscheinungsjahr 2021
Department CATHYD
Band/Volume 35
Heft 3
Seite von e14077
Sprache englisch
Topic T5 Future Landscapes
Daten-/Softwarelinks https://doi.org/10.1594/PANGAEA.921389
Supplements https://onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2Fhyp.14077&file=hyp14077-sup-0001-Supinfo.pdf
Keywords Actual evapotranspiration; ground heat flux; groundwater recharge; Hydrus; irrigation; net radiation; Sentinel‐2; soil moisture
Abstract

Information on water balance components such as evapotranspiration and groundwater recharge are crucial for water management. Due to differences in physical conditions, but also due to limited budgets, there is not one universal best practice, but a wide range of different methods with specific advantages and disadvantages. In this study, we propose an approach to quantify actual evapotranspiration, groundwater recharge and water inflow, i.e. precipitation and irrigation, that considers the specific conditions of irrigated agriculture in warm, arid environments. This approach does not require direct measurements of precipitation or irrigation quantities and is therefore suitable for sites with an uncertain data basis. For this purpose, we combine soil moisture and energy balance monitoring, remote sensing data analysis and numerical modeling using Hydrus. Energy balance data and routine weather data serve to estimate ET0. Surface reflectance data from satellite images (Sentinel‐2) are used to derive leaf area indices, which help to partition ET0 into energy limited evaporation and transpiration. Subsequently, first approximations of water inflow are derived based on observed soil moisture changes. These inflow estimates are used in a series of forward simulations that produce initial estimates of drainage and ETact, which in turn help improve the estimate of water inflow. Finally, the improved inflow estimates are incorporated into the model and then a parameter optimization is performed using the observed soil moisture as the reference figure. Forward simulations with calibrated soil parameters result in final estimates for ETact and groundwater recharge.

The presented method is applied to an agricultural test site with a crop rotation of cotton and wheat in Punjab, Pakistan. The final model results, with an RMSE of 2.2% in volumetric water content, suggest a cumulative ETact and groundwater recharge of 769 mm and 297 mm over a period of 281 days, respectively. The total estimated water inflow accounts for 946 mm, of which 77% originates from irrigation.

dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=24279
Schulz, S., Becker, R., Richard‐Cerda, J.C., Usman, M., aus der Beek, T., Merz, R., Schüth, C. (2021):
Estimating water balance components in irrigated agriculture using a combined approach of soil moisture and energy balance monitoring, and numerical modeling
Hydrol. Process. 35 (3), e14077 10.1002/hyp.14077