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| Titel |
Monitoring and modelling of soil–plant interactions: the joint use of ERT, sap flow and eddy covariance data to characterize the volume of an orange tree root zone |
| VerfasserIn |
G. Cassiani, J. Boaga, D. Vanella, M. T. Perri, S. Consoli |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 5 ; Nr. 19, no. 5 (2015-05-08), S.2213-2225 |
| Datensatznummer |
250120707
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| Publikation (Nr.) |
 copernicus.org/hess-19-2213-2015.pdf |
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| Zusammenfassung |
| Mass and energy exchanges between soil, plants and atmosphere control a
number of key environmental processes involving hydrology, biota and
climate. The understanding of these exchanges also play a critical role for
practical purposes e.g. in precision agriculture. In this paper we present a
methodology based on coupling innovative data collection and models in order
to obtain quantitative estimates of the key parameters of such complex flow
system. In particular we propose the use of hydro-geophysical monitoring via
"time-lapse" electrical resistivity tomography (ERT) in conjunction with
measurements of plant transpiration via sap flow and evapotranspiration (ET) from
eddy covariance (EC). This abundance of data is fed to spatially distributed
soil models in order to characterize the distribution of active roots. We
conducted experiments in an orange orchard in eastern Sicily (Italy),
characterized by the typical Mediterranean semi-arid climate. The subsoil
dynamics, particularly influenced by irrigation and root uptake, were
characterized mainly by the ERT set-up, consisting of 48 buried electrodes on
4 instrumented micro-boreholes (about 1.2 m deep) placed at the corners of a
square (with about 1.3 m long sides) surrounding the orange tree, plus 24
mini-electrodes on the surface spaced 0.1 m on a square grid. During the
monitoring, we collected repeated ERT and time domain reflectometry (TDR) soil moisture measurements,
soil water sampling, sap flow measurements from the orange tree and EC data.
We conducted a laboratory calibration of the soil electrical properties as a
function of moisture content and porewater electrical conductivity.
Irrigation, precipitation, sap flow and ET data are available allowing for
knowledge of the system's long-term forcing conditions on the system. This
information was used to calibrate a 1-D Richards' equation model representing
the dynamics of the volume monitored via 3-D ERT. Information on the soil
hydraulic properties was collected from laboratory and field experiments.
The successful results of the calibrated modelling exercise allow for the
quantification of the soil volume interested by root water uptake (RWU). This
volume is much smaller (with a surface area less than 2 m2, and
about 40 cm thick) than expected and assumed in the design of classical
drip irrigation schemes that prove to be losing at least half of the
irrigated water which is not taken up by the plants. |
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