TY - JOUR
T1 - Detecting soil water use by Mediterranean vegetation on rocky soils using electrical resistivity tomography.
AU - Nijland, W.
AU - van der Meijde, M.
AU - Addink, E. A.
AU - de Jong, S. M.
AU - van der Meer, F. D.
N1 - EGU General Assembly 2009
PY - 2009/4/1
Y1 - 2009/4/1
N2 - Water availability is an important constraint on tree and shrub
development in Mediterranean ecosystems. During prolonged periods of
summer drought, water stored in the soil column is the only available
water source. Some Mediterranean tree species are known to have
extensive root system penetrating deeply into fractured bedrock.
Accurate characterisation of the soil and the ability of trees to
subtract water from the soil profile are crucial for the understanding
of Mediterranean ecosystems and the modelling of primary production.
However, with shallow soils on rocky substrate, it is hard to obtain
soil moisture data at depths below 30-50 cm. We explored the use of
Electrical Resistivity Tomography (ERT) to detect vegetation water use
trough the whole soil column. ERT provides spatial information on soil
conditions and moisture content down to 5 m and deeper in a 2D
cross-section. It uses a multi-electrode array that is connected to the
soil through steel pins that are inserted in the ground. This method of
installation allows measurements on rocky substrate. We used ERT to
detect spatial and temporal patterns of soil moisture in variable
shallow soils and weathered bedrock of the Peyne area in Mediterranean
southern France. The Peyne area has a sub-humid climate and is covered
mainly in sclerophyllous trees and shrubs. ERT measurements were made
for 13 sites in the study area which were all visited in June, at the
onset of the dry season, and again in September, near the end of a
three-month dry period. Our measurements show root penetration and water
use by trees 5m and deeper, despite the shallow soils in the study area.
We also show large short-scale spatial variability and the importance of
the geological substrate in moisture processes. ERT is a useful new
technique for the exploration of soil and ecosystem functioning, even
with rocky soils, providing information on rooting depth and water use
otherwise unavailable.
AB - Water availability is an important constraint on tree and shrub
development in Mediterranean ecosystems. During prolonged periods of
summer drought, water stored in the soil column is the only available
water source. Some Mediterranean tree species are known to have
extensive root system penetrating deeply into fractured bedrock.
Accurate characterisation of the soil and the ability of trees to
subtract water from the soil profile are crucial for the understanding
of Mediterranean ecosystems and the modelling of primary production.
However, with shallow soils on rocky substrate, it is hard to obtain
soil moisture data at depths below 30-50 cm. We explored the use of
Electrical Resistivity Tomography (ERT) to detect vegetation water use
trough the whole soil column. ERT provides spatial information on soil
conditions and moisture content down to 5 m and deeper in a 2D
cross-section. It uses a multi-electrode array that is connected to the
soil through steel pins that are inserted in the ground. This method of
installation allows measurements on rocky substrate. We used ERT to
detect spatial and temporal patterns of soil moisture in variable
shallow soils and weathered bedrock of the Peyne area in Mediterranean
southern France. The Peyne area has a sub-humid climate and is covered
mainly in sclerophyllous trees and shrubs. ERT measurements were made
for 13 sites in the study area which were all visited in June, at the
onset of the dry season, and again in September, near the end of a
three-month dry period. Our measurements show root penetration and water
use by trees 5m and deeper, despite the shallow soils in the study area.
We also show large short-scale spatial variability and the importance of
the geological substrate in moisture processes. ERT is a useful new
technique for the exploration of soil and ecosystem functioning, even
with rocky soils, providing information on rooting depth and water use
otherwise unavailable.
M3 - Meeting Abstract
SN - 1029-7006
VL - 11
JO - Geophysical Research Abstracts
JF - Geophysical Research Abstracts
M1 - EGU2009-7067
T2 - EGU General Assembly 2009
Y2 - 19 April 2009 through 24 April 2009
ER -