Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters
Monitoring and modelling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary...
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doaj-ec219e6e58b241ac81a3ff2f3d70a9902020-11-24T20:53:21ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382016-01-0120148750310.5194/hess-20-487-2016Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parametersM. Rezaei0P. Seuntjens1I. Joris2W. Boënne3S. Van Hoey4P. Campling5W. M. Cornelis6Department of Soil Management, Ghent University, Coupure Links 653, 9000 Ghent, BelgiumDepartment of Soil Management, Ghent University, Coupure Links 653, 9000 Ghent, BelgiumUnit Environmental Modelling, Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, BelgiumUnit Environmental Modelling, Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, BelgiumDepartment of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, 9000 Ghent, BelgiumUnit Environmental Modelling, Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400 Mol, BelgiumDepartment of Soil Management, Ghent University, Coupure Links 653, 9000 Ghent, BelgiumMonitoring and modelling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. The sensitivity of the soil hydrological model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed after integrating models. Free drainage and incremental constant head conditions were implemented in a lower boundary sensitivity analysis. A time-dependent sensitivity analysis of the hydraulic parameters showed that changes in soil water content are mainly affected by the soil saturated hydraulic conductivity <i>K</i><sub>s</sub> and the Mualem–van Genuchten retention curve shape parameters <i>n</i> and <i>α</i>. Results further showed that different parameter optimization strategies (two-, three-, four- or six-parameter optimizations) did not affect the calculated water stress and water content as significantly as does the bottom boundary. In this case, a two-parameter scenario, where <i>K</i><sub>s</sub> was optimized for each layer under the condition of a constant groundwater depth at 135–140 cm, performed best. A larger yield reduction, and a larger number and longer duration of stress conditions occurred in the free drainage condition as compared to constant boundary conditions. Numerical results showed that optimal irrigation scheduling using the aforementioned water stress calculations can save up to 12–22 % irrigation water as compared to the current irrigation regime. This resulted in a yield increase of 4.5–6.5 %, simulated by the crop growth model.http://www.hydrol-earth-syst-sci.net/20/487/2016/hess-20-487-2016.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
M. Rezaei P. Seuntjens I. Joris W. Boënne S. Van Hoey P. Campling W. M. Cornelis |
spellingShingle |
M. Rezaei P. Seuntjens I. Joris W. Boënne S. Van Hoey P. Campling W. M. Cornelis Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters Hydrology and Earth System Sciences |
author_facet |
M. Rezaei P. Seuntjens I. Joris W. Boënne S. Van Hoey P. Campling W. M. Cornelis |
author_sort |
M. Rezaei |
title |
Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters |
title_short |
Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters |
title_full |
Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters |
title_fullStr |
Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters |
title_full_unstemmed |
Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters |
title_sort |
sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters |
publisher |
Copernicus Publications |
series |
Hydrology and Earth System Sciences |
issn |
1027-5606 1607-7938 |
publishDate |
2016-01-01 |
description |
Monitoring and modelling tools may improve irrigation strategies in precision
agriculture. We used non-invasive soil moisture monitoring, a crop growth
and a soil hydrological model to predict soil water content fluctuations and
crop yield in a heterogeneous sandy grassland soil under supplementary
irrigation. The sensitivity of the soil hydrological model to hydraulic
parameters, water stress, crop yield and lower boundary conditions was
assessed after integrating models. Free drainage and incremental constant
head conditions were implemented in a lower boundary sensitivity analysis. A
time-dependent sensitivity analysis of the hydraulic parameters showed that
changes in soil water content are mainly affected by the soil saturated
hydraulic conductivity <i>K</i><sub>s</sub> and the Mualem–van Genuchten retention curve
shape parameters <i>n</i> and <i>α</i>. Results further showed that different
parameter optimization strategies (two-, three-, four- or six-parameter
optimizations) did not affect the calculated water stress and water content
as significantly as does the bottom boundary. In this case, a two-parameter
scenario, where <i>K</i><sub>s</sub> was optimized for each layer under the condition of a constant groundwater depth at 135–140 cm, performed best. A larger yield
reduction, and a larger number and longer duration of stress conditions
occurred in the free drainage condition as compared to constant boundary
conditions. Numerical results showed that optimal irrigation scheduling
using the aforementioned water stress calculations can save up to 12–22 %
irrigation water as compared to the current irrigation regime. This resulted
in a yield increase of 4.5–6.5 %, simulated by the crop growth model. |
url |
http://www.hydrol-earth-syst-sci.net/20/487/2016/hess-20-487-2016.pdf |
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