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MINIMALLY INVASIVE MONITORING OF SOIL-

PLANT INTERACTIONS:

NEW PERSPECTIVES

Giorgio Cassiani

Dipartimento di Geoscienze, Università di Padova, Italy

[email protected]

SUMMARY q Soil-plant-atmosphere interactions

q  Characterization of the Earth’s critical zone: the role of non-invasive monitoring

q  Large-scale monitoring

q Small-scale monitoring

q Outlook: assimilate data and models, with a vision

q  Conclusions

SUMMARY q Soil-plant-atmosphere interactions

q  Characterization of the Earth’s critical zone: the role of non-invasive monitoring

q  Large-scale monitoring

q Small-scale monitoring

q Soil – plant interaction modelling

q  Conclusions and outlook

The Earth’s Critical Zone

Na#onal  Research  Council  (2001)  

The Earth’s Critical Zone (CZ) is the thin outer veneer of our planet from the top of the tree canopy to the bottom of our drinking water aquifers. The CZ supports almost all human activity. Understanding, predicting and managing intensification of land use and associated economic services, while mitigating and adapting to rapid climate change and biodiversity decline, is now one of the most pressing societal challenges of the 21st century. Particular attention shall be devoted to the soil-plant-atmosphere (SPA) interactions.

mass  

energy  

Soil-plant-atmosphere interactions are important

Pe

Pi

P

ET

Atmospheric

Input

Atmospheric

Output

Incoming

Runoff

Outgoing

Runoff

Study Region

Global water cycle Regional water recycling

Terrestrial Carbon cycle

Crop responses to… courtesy:  M.  Marani  

vegetated soil

Soil moisture dynamics in vegetated and bare soils

Volp

e et

al.,

201

3

bare soil

courtesy:  M.  Marani  

Transpiration and Photosynthesis

courtesy:  M.  Marani  

Importance of root distribution (li) in determining

overall resistance to flow. courtesy:  M.  Marani  

Geophysical techniques, combined with flow and transport models, can provide a major step

forward in the ECZ characterization

Key idea

SUMMARY q Soil-plant-atmosphere interactions

q  Characterization of the Earth’s critical zone: the role of non-invasive monitoring

q  Large-scale monitoring

q Small-scale monitoring

q Outlook: assimilate data and models, with a vision

q  Conclusions

water table

aquifer confining layer

impermeable bedrock

small scale large scale

What geophysical methods can help define

q  structure / texture

water table

spring evapo-transpiration

water table

aquifer confining layer

impermeable bedrock

small scale large scale

q  structure / texture

q  fluid-dynamics

What geophysical methods can help define

Geophysical measurements

Physical model

(e.g hydrologic)

physical parameters (e.g. hydraulic conductivity)

dynamics (fluids,

temperature)

structure (geometry, geology)

Integrate measurements and physical models that explain the space-time evolution of state variables (e.g. moisture content, solute concentration and temperature) that affect the space-time changes of geophysical response.

GOAL

SUMMARY q Soil-plant-atmosphere interactions

q  Characterization of the Earth’s critical zone: the role of non-invasive monitoring

q  Large-scale monitoring

q Small-scale monitoring

q Outlook: assimilate data and models, with a vision

q  Conclusions

Digital Soil Mapping

Bregonze Hills

Bregonze project description

Goal: characterize hydrological response of a small hill catchment in the Veneto pre-Alps

Geology: altered volcanic rocks

(basalts, tuffs, breccias)

catchment boundaries

Bregonze catchment Small, self-contained primary catchment, with mild slope and grass cover Only the stream bed is populated by high trees and dense vegetation.

April

April

Frequency-domain

electromagnetics

18/08/2014

creek

Frequency-Domain Electro-Magnetics

Resistivity map obtained using a GF Instrument CMD 1 sonde: max investigation depth 0.75 m

02/09/2014

Frequency-Domain Electro-Magnetics

Resistivity map obtained using a GF Instrument CMD 1 sonde: max investigation depth 0.75 m

creek

22/09/2014

Frequency-Domain Electro-Magnetics

Resistivity map obtained using a GF Instrument CMD 1 sonde: max investigation depth 0.75 m

creek

10/10/2014

Frequency-Domain Electro-Magnetics

Resistivity map obtained using a GF Instrument CMD 1 sonde: max investigation depth 0.75 m

creek

Matching model predictions and EM data

Monitoring over time and space the soil moisture conditions (e.g. via FDEM) can give

critical information for model calibration

Full scale 3D catchment model (CATHY)

AGRIS San Michele experimental farm - Ussana - Sardinia

field 21

field 11

FP7 EU collaborative project

Digital soil mapping using frequency-domain EM

Soil texture pattern effect - ECa

Electrical conductivity (mS/m)

Soil texture pattern effect – gamma ray spectrometry

doserate [mG/hr]

508700 508750 508800 508850 508900 508950Easting (m)

May 18, 2009

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

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electricalconductivity

mS/m

Soil texture

508650 508700 508750 508800 508850 508900 508950 509000

UTM easting (m)

total dose rate (nG/h)

4362450

4362500

4362550

4362600

4362650

4362700

4362750

4362800

UTM

nor

thin

g (m

)

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field 21

508975, 4362850

508585, 4362460 +

+

508650 508700 508750 508800 508850 508900 508950 509000

UTM easting (m)

CaCO3 %

4362450

4362500

4362550

4362600

4362650

4362700

4362750

4362800

UTM

nor

thin

g (m

)

0246810121416182022242628303234

508700 508750 508800 508850 508900 508950Easting (m)

May 18, 2009

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

10

15

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electricalconductivity

mS/m

Field 21 – May 18, 2009

508700 508750 508800 508850 508900 508950Easting (m)

June 15, 2009

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

10

15

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electricalconductivity

mS/m

Field 21 – June 15, 2009

508700 508750 508800 508850 508900 508950Easting (m)

March 31, 2010

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

10

15

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electricalconductivity

mS/m

Field 21 – March 31, 2010

508700 508750 508800 508850 508900 508950Easting (m)

May 19, 2010

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

10

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electricalconductivity

mS/m

Field 21 – May 19, 2010

508700 508750 508800 508850 508900 508950Easting (m)

February 3, 2011

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

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electricalconductivity

mS/m

Field 21 – Feb 3, 2011

Time-lapse EM results

508700 508750 508800 508850 508900 508950Easting (m)

May 19, 2010

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

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10

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electricalconductivity

mS/m

508700 508750 508800 508850 508900 508950Easting (m)

May 18, 2009

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

10

15

20

25

30

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electricalconductivity

mS/m

508700 508750 508800 508850 508900 508950Easting (m)

May 19, 2010

4362500

4362550

4362600

4362650

4362700

4362750

Nor

thin

g (m

)

0

5

10

15

20

25

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35

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45

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electricalconductivity

mS/m

This area is considerably drier than the bare soil

area planted with wheat

in January 2010

bare soil

bare soil

vegetated soil

vegetated soil

a 507900 507950 508000 508050 508100 508150

UTM easting (m)

total dose rate (nG/h)

4362400

4362450

4362500

4362550

4362600

UTM

nor

thin

g (m

)

95

97

99

101

103

105

107

109

b

c d

field 23 508265, 4362675

507935, 4362375 +

+

Fallow plot Cultivated plot alfalfa (Medicago sativa L.)

Field 11 – May 18 2010 – before irrigation

508015 508020 508025 508030 508035 508040 508045 508050 508055 508060 508065 508070Easting (m)

Twin fields - background - May 18 2010

4362515

4362520

4362525

4362530

4362535

4362540

4362545

4362550

4362555

4362560

4362565N

orth

ing

(m)

0

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0

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bare (fallow) soil

vegetated soil

508700 508750 508800 508850 508900 508950Easting (m)

May 19, 2010

4362500

4362550

4362600

4362650

4362700

4362750N

orth

ing

(m)

0

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10

15

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electricalconductivity

mS/m

ERT line 2

TDR probes

ERT line 1

0.5 1 1.5 2 2.5 3 3.5 4 4.5

P0

-0.5

10

15

20

25

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45

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55

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0.5 1 1.5 2 2.5 3 3.5 4 4.5

P1

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

P2

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

P5

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

P12

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA0

-0.5

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0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA1

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA2

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA5

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA12

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA0

-0.5

10

15

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80

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA1

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA2

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA5

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

NA12

-0.5

electrical  resis#vity  (Ohm  m)  

May  24  15:30  

May  19  17:30  

May  20    9:30  

42  mm  irriga#on  during  night  

13  mm  rainfall  during  night  

May  20  12:30  

May  21  10:30  

line  2  bare  soil  

line  1  vegetated  soil  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

meters  

Vegetation changes the distribution of moisture content and also the soil structure and its hydraulic properties

0.12 0.16 0.2 0.24 0.28 0.32

theta (-)

-1

-0.8

-0.6

-0.4

-0.2

0de

pth

(m)

TDRs on May 19TDRs on May 24TRASE on May 19ERT calibrated on May 19 ERT calibrated on May 24

Calibration of electrical resistivity tomography inversion results against in situ time domain reflectometry measurements of moisture content over the vegetated plot. The curves of moisture content as a function of depth are obtained taking the horizontal averages of the line 1 electrical resistivity tomography resistivity images, transforming resistivity into moisture content values using a Waxman and Smits (1968) formulation.

0.1 1

saturation (-)

1

10

100

1000

resi

stiv

ity (O

hm m

)

Laboratory data on soil samples from the San Michele farm (diamonds) compared against the field-calibrated Waxman and Smits relationship

0.5 1 1.5 2 2.5 3 3.5 4 4.5

P12

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

P12 entire sintetico

-0.5

0.5 1 1.5 2 2.5 3 3.5 4 4.5

P12 65 cm sintetico

-0.5

10

15

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Line  1:  synthe<c  (b)  May  24  15:30  

Line  1:  measured  May  24  15:30  

Line  1:  synthe<c  (a)  May  24  15:30  

12 16 20 24 28

resistivity (Ohm m)

-2

-1.6

-1.2

-0.8

-0.4

0

dept

h (m

)

synthetic (a): extrapolated inverted profile synthetic (b):higher resistivity below 0.63 m

Sensitivity analysis with respect to the actual resistivity profile below 0.6 m, that is, the depth down to which the electrical resistivity tomography inversion is considered reliable.

moisture    content  

(-­‐)  

May  19  17:30  

May  20    9:30  

May  20  12:30  

May  21  10:30  

May  24  15:30  

13  mm  precipita#on  during  night  

42  mm  irriga#on  during  night  

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

P0

-0.5

meters

0

0.025

0.05

0.075

0.1

0.125

0.15

0.175

0.2

0.225

0.25

0.275

0.3

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

P0

-0.5

meters

0

0.025

0.05

0.075

0.1

0.125

0.15

0.175

0.2

0.225

0.25

0.275

0.3

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

P1

-0.5meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

P2

-0.5

meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

P5

-0.5

meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

P12

-0.5

meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

NA0

-0.5

meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

NA1

-0.5

meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

NA2

-0.5

meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

NA5

-0.5

meters

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

NA12

-0.5meters

line  2  bare  soil  

line  1  vegetated  soil  

0.51

1.52

2.53

3.54

4.5

NB

5 over 0 - 1%

-0.5

50 55 60 65 70 75 80 85 90 95 100

105

110

115

120

125

% resistivity change w.r.t. background (19/05/10)

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

line NA: 24/05/10 15:35

-0.5

met

ers

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

line NA: 23/05/10 9:40

-0.5

met

ers

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

line NA: 22/05/10 10:30

-0.5

met

ers

0.5 1 1.5 2 2.5 3 3.5 4 4.5

meters

line NA: 20/05/10 9:40

-0.5

met

ers

line  2:  bare  soil  (fallow  plot)  

Complex behavior seems to call into play important pore water salinity (and old vs new water) issues

SUMMARY q Soil-plant-atmosphere interactions

q  Characterization of the Earth’s critical zone: the role of non-invasive monitoring

q  Large-scale monitoring

q Small-scale monitoring

q Outlook: assimilate data and models, with a vision

q  Conclusions

TIME LAPSE MICRO-ERT in the Venice Lagoon

Aim: are marsh plants able to induced a permanent aerated layer when flooded ? Marani et al. 2006, WRR

- 24 buried electrodes + 24 surface elect. -  0.1 m spacing -  Time-lapse skip0 dip-dip (pre, during and

after flooding) -  6 Tensiometers in depth

TIME LAPSE MICRO-ERT in the Venice Lagoon

July 2012 experiment: resistivity ratio with respect to background at 3 time steps during marsh flooding

Dryer zone at roots depth Boaga et al. 2014, GRL

TIME LAPSE MICRO-ERT in the Venice Lagoon

Dryer zone at 30-40 cm

depth

Water level

Confirmed by tensiometers

TIME LAPSE MICRO-ERT in the Venice Lagoon

Boaga et al. 2014, GRL

Dryer zone at roots depth

TIME LAPSE MICRO-ERT in the Venice Lagoon

Boaga et al. 2014, GRL

CLES, val di Non, Trentino Noce catchment apple orchard

sandy-silty soil with no clay

4 PVC tubes Length =120 cm; Ø= 1 inch Totally internal wiring Built with 10 cm water-tight segments to allow internal link operability Stainless steel circular electrodes with height of 3 cm

Construction of the micro ERT cross-borehole system

Resistivimeter SYSCAL pro 72 channels (48 in boreholes, 24 on surface)

Field deployment -  Installation without

pre dig for the max electrode-soil coupling

- Selected an apple tree already monitored

-  by other means -  ( d i e l e c t r i c

probes)

Acquisition scheme

A complete skip-0 dipole-dipole scheme

with reciprocal was used for al l

acquisitions.

ERT inversion

Using the ERT code R3T (A.Binley, Lancaster University)

Date   Note  

15/10/10   Installation and Measurement 1  

14/01/11   Measurement 2  

04/04/11   Measurement 3  

28/04/11   Measurement 4  

18/05/11   Measurement 5  

06/07/11   Measurement 6  

04/08/11   Measurement 7 + Irrigation TEST  

07/09/11   Measurement 8  

05/10/11   Measurement 9  

03/05/12   Measurement 10 + Irrigation TEST  

04/11/12   Measurement 11 + Irrigation TEST  

Repeated (seasonal) measurements

Irrigation tests

Three irrigation tests: August 2011, May 2012, November 2012

August 2011: irrigation performed via two drippers on the ground surface: total flow rate =2.4 l/h for six hours, following a long dry period. May 2012: widespread irrigation performed with a sprinkler ; total water volume = 500 l over 2.5 hours, at the top of growing season. November 2012: widespread irrigation performed with a sprinkler ; total water volume = 500 l over 5 hours, wet period following apple harvest (low ET).

August 2011 experiment: resistivity ratio with respect to background at four time steps. The iso-surface equal to 60 % of the background resistivity does not penetrate any deeper than 30-40 cm below ground surface.

May 2012 experiment: resistivity ratio with respect to background at four time steps shown on the horizontal slice at 30 cm depth.

Moisture content measured by TDR in the top 32 cm. The moisture content was already high at the start of the experiment.

May 2012 experiment: resistivity ratio with respect to background at 30 cm depth and at 8.5 hours after start of irrigation

%

0 Resistivity ratio w.r.t. background

100

200

300 30 cm depth

root

suction zone ?

November 2012 experiment: resistivity ratio with respect to background at four time steps.

Moisture content measured by TDR in the top 32 cm. The initial moisture content is higher than other experiments, low ET

May 2012 experiment: resistivity ratio with respect to background averaged over horizontal slices

0.5 h after irrigation start irrigation end at 2.5 h

root suction Zone

?

May 2012 experiment: resistivity changes converted into saturation changes and averaged along horizontal planes.

0.5 h after irrigation start irrigation end at 2.5 h

Archie’s law from lab

root suction Zone

?

Rho

Sw

November 2012 experiment: resistivity ratio with respect to background averaged over horizontal slices

0.5 h after irrigation start 2.5 h after irrigation start

?

May 2012 experiment: mass balance issue from 3D ERT

Note that the total irrigated water amounts to 500 liters

We applied the CATHY (CATchment HYdrology) model [Bixio et al, 2000; Camporese et al., 2010], a physically-based 3D distributed model which uses Richards’ equation to describe variably saturated flow in porous media. We used the following parameters: Ks = 6x10-5 m/s Van Genuchten n = 1.35 Porosity = 0.5 θr = 8x10-2 ψa = -0.7

Sw

ψ

Time = 2 hours

tracking of particle motion starting from the surface

May 2012 experiment

Volume of interest

Pseudo-color Var-saturation

Dep

th m

m

Time = 3 hours

tracking of particle motion starting from the surface

May 2012 experiment

Pseudo-color Var-saturation

Dep

th m

m

Volume of interest

Time = 5 hours

tracking of particle motion starting from the surface

May 2012 experiment

Pseudo-color Var-saturation

Dep

th m

m

Volume of interest

Time = 3 hours May 2012 experiment

Pseudo-color Var-saturation

Dep

th m

m

Volume of interest

Time = 3 hours

November and May irrigation

experiment

Dep

th m

m

(240 μS/cm)

Pseudo-color Var-saturation

Piston effect ?

Again: important pore water salinity (and old vs new water) issues

The Bulgherano – Lentini field site

Orange  trees  

Lentini (SR) •   October  2013:  meas.  living  plant,  irriga#on  test  •   June  2014:  meas.  dead    plant;  

Eddy covariance tower

Sap flow probes

The Bulgherano – Lentini field site

Surface  electrodes  

Borehole  electrodes  Sap  flow  probes  

Surface  electrodes  

Borehole  electrodes  

3D ERT monitoring scheme •  24 superficial electrodes covering a 1.3x1.3 m2 area •  48 borehole electrodes, 12 in each of the 4 micro-boreholes •  Acquisition using a complete skip-0 dipole-dipole scheme with reciprocal

was used for all acquisitions. •  Inversion using the ERT code R3t (A.Binley, Lancaster University)

1.3  m  1.3  m  

1.2  m  

ORANGE TREE

0-­‐40  cm:  Dry  region  influenced  by  root  water  uptake  

Resistivity (Ω m)

Irrigation test: background conditions

Clouds

Transpiration

z

ABL

Free Atmosphere

sunrise mid-morning

Soil

Plan

t A

tmos

pher

e

mid-afternoon courtesy:  M.  Marani  

hours

Time-lapse monitoring during irrigation (4 liters/min per dripper, 4 drippers per tree – spaced 1 m)

October 2-3, 2013

eddy covariance sap flow

Convert resistivity into moisture content laboratory tests

(with due care to pore water electrical conductivity, water extracted in situ via suction cups)

θ =4.703ρ1.12

Archie’s law (1942)

Resistivity ratio with respect to background(%)

June 2014 irrigation test (the orange tree is dead)

Indipendent calibration of unsaturated flow model (in absence of tree transpiration) for in situ saturated hydraulic conductivity Ks = 0.002 m/h  

From laboratory experiments: pressure –saturation parameters: residual moisture content θr = 0., porosity θs=0.54, α = 0.12 1/m, n = 1.6.

We know the total water extracted by the tree (sap flow measurements) We have to estimate the fraction extracted from this square meter, i.e. the radius of the root water uptake area.

irrigation and rainfall (input)

1 m 1 m

0.4 m root water uptake (output)

Conceptual scheme of 1D infiltration modelling

1 m

drippers orange trees TDR

0 0.2 0.4 0.6

soil moisture content (-)

-2

-1.6

-1.2

-0.8

-0.4

0

dept

h be

low

gro

und

(m)

real data: 12:00 noonOctober 2, 2013initial conditions (1/1/2013)1.75 m2

1.50 m2

1.25 m2

2.00 m2

2.25 m2

Results of 1D infiltration modelling

radius ≈ 0.75 m

0.300

0.320

0.340

0.360

0.380

0.400

0.420

0.440

27/09/20

13

28/09/20

13

29/09/20

13

30/09/20

13

01/10/20

13

02/10/20

13

03/10/20

13

04/10/20

13

05/10/20

13

06/10/20

13

07/10/20

13

08/10/20

13

Soilmoistureconten

t(-­‐)

TDR  at  20  cm  depth

TDR  at  35  cm  depth

TDR  at  45  cm  depth

1 m

drippers trees TDR

The TDR data provide independent supporting evidence that the root water uptake zone has a radius smaller than the distance between the TDR probes and the orange tree trunk (about 0.75 m).

SUMMARY q Soil-plant-atmosphere interactions

q  Characterization of the Earth’s critical zone: the role of non-invasive monitoring

q  Large-scale monitoring

q Small-scale monitoring

q Outlook: assimilate data and models, with a vision

q  Conclusions

“I believe that the spatiotemporal linkage between the hydrologic and ecologic dynamics will be one of the most exciting frontiers of the future.” (Ignacio Rodriguez-Iturbe, 2000). “A radicle may be compared with a burrowing mole, which wishes to penetrate perpendicularly into the ground. By continually moving its head from side to side, or circumnutating, he will feel a stone or other obstacle as well as any difference in the hardness of the soil, and he will turn from that side; if the earth is damper on one than the other side he will turn thitherward as a better hunting ground. Nevertheless, after each interruption, guided by the sense of gravity, he will be able to recover his downward course and burrow to a greater depth.” (Charles Darwin, The Power of Movement in Plants, 1881).

Conceptual plant model indicating mesh nodes of richards’ equation solver and the distribution of the plant water flux paths. The model is based on an optimality criterion maximizing plant transpiration.

Outlook

Soil-plant-atmosphere continuum model

ΨR  

ΨL  

CO2

gx  

gs  gs  

T  

H2O

Volpe et al., 2013; Manoli et al., 2014

( ) ( )[ ] xRRLLxLR AzzψgT ⋅+−+⋅−= ψψψ ),(

( ) ( )[ ] riiRRiLRi Azzgq ⋅+−+⋅−= ψψψψ ),(

cwLsLw ALAIVPDgaf ⋅⋅⋅⋅⋅= εψψ )()(

Soil-Plant-Atmosphere continuum model Leaf-Atmosphere

Xylem-Leaf

Root-Xylem ΨR  

ΨL  

CO2

gx  

gs  gs  

T  

0=∂

∂−

s

w

s

c

gf

gf

λ

(Katul et al., 2010)

( )Lsg ψ

( )[ ] ( )Lrsw

ws qzKKtS

tSS ψψψϕ

ψ ,++∇⋅∇=∂

∂+

Variably saturated flow (Cathy):

H2O

(Volpe et al., 2011)

Volpe et al., 2013; Manoli et al., 2014 (Paniconi and Putti, 1994)

RWU RWU

Root Hydraulic Redistribution Root Hydraulic Redistribution

Darcy flow divergence Darcy flow divergence

Root

Hyd

raulic R

edistr

ibut

ion

and

spat

ial inte

ract

ions

Man

oli e

t al

., 20

14

Soil-Plant-Atmosphere Interactions: Roots as Optimal Organized Transport Systems

The root systems of corn from J. E. Weaver, F. C. Jean, J. W. Crist, Development and Activities of Roots of Crop Plants (Carnegie Institute,Washington, DC, 1922).

Directional drilling configuration (together with a 3D seismic cube) From http://www.dgi.com/earthvision/evmain.html

courtesy:  M.  Pu7  

12.5  m

8  m

2 m1.3  m2.5  m

soildrain (gravel)

soildrain (gravel)

12.5  m

12.5  m

5.5m  x  2.5m 5.5m  x  2.5m

5.5m  x  2.5m

2m  x  

2.5m

3m  x  2.5m

2m  x  

2.5m

3m  x  2.5m

2m  x  

2.5m

3m  x  2.5m

schematic plan and side view of the greenhuse. In planar view observe the different sizes of the lysimeters and a tentative placement of the ERT micro-boreholes (red dots – shown only for some lysimeters).

Roots as Optimal Organized Transport Systems

Need for full scale controlled experiments

q  Near surface geophysics is strongly affected by both static and dynamic soil/subsoil characteristics.

q  This fact, if properly recognized, is potentially full of information on the Critical Zone dynamic behaviour, and particularly for the root zone.

q  Integration with physical modelling is essential to capture the meaning of space-time signal changes.

q  Exciting frontiers will be opened if high resolution geophysics can monitor processes to prove / disprove fundamental theories.

Conclusions

FUNDING FROM: -  EU FP7 iSOIL -  EU FP7 CLIMB -  EU FP7 GLOBAQUA - MIUR PRIN 2011 “Innovative methods for water resources management

under hydro-climatic uncertainty scenarios”

Acknowledgements MARCO MARANI, MARTA ALTISSIMO, PAOLO SALANDIN, MATTEO CAMPORESE, MARIO PUTTI, NADIA URSINO, RITA DEIANA, JACOPO BOAGA, MATTEO ROSSI, MARIATERESA PERRI Università di Padova ALBERTO BELLIN, BRUNO MAJONE Università di Trento

SIMONA CONSOLI, DANIELA VANELLA Università di Catania STEFANO FERRARIS Università di Torino

ANDREW BINLEY Lancaster University

Thanks for your attention