To what extent does water content next to preferential flow paths influence colloid retention in structured soils

HAL Id: hal-01601547

https://hal.archives-ouvertes.fr/hal-01601547

Submitted on 5 Jun 2020

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Distributed under a Creative Commons Attribution - ShareAlike| 4.0 International License

To what extent does water content next to preferential

flow paths influence colloid retention in structured soils

Eric Michel, Romain van den Bogaert, Loys Mesnier, Sophie Cornu

To cite this version:

Eric Michel, Romain van den Bogaert, Loys Mesnier, Sophie Cornu. To what extent does water content next to preferential flow paths influence colloid retention in structured soils. International symposium 2014 of german priority programme SPP 1315 on biogeochemical interfaces in soil – toward a comprehensive and mechanistic understanding of soil functions., Oct 2014, Leipzig, Germany. �hal-01601547�

Laser

Fluorescence

Light scattering

Sample

Hydrodynamic

Focussing

To what extent does water content next to preferential flow path

influence colloid retention in structured soils?

R. Van den Bogaert

(1,2,3)

_{, E. Michel}

(1,2)

_{, L. Mesnier}

(1,2)

_{, S. Cornu}

(3)

(1)

_{INRA, Avignon, France}

(2)

_{Avignon University, France,}

(3)

_{INRA, Aix en Provence, France}

1- Colloid fate in soil impacts…

2- Successive rainfalls on undisturbed soil cores

4- Microspheres from rain n recovered

at rain n+1 and n+2

3 – Duration of rain interruption

affects:

Soil evolution

Water quality

////////////////

rain

surface

ground

water

soil

////////////////

rain

////////////////

rain

surface

ground

water

soil

predictive models of

particle fate

↑

better understanding of

mobilization & retention

mechanisms

6-Proposed mechanisms

Matrix close to macropore

Macropore

Water in macropore

Matrix far from

macropore

Ret

e

n

ti

o

n

at

ra

in

#

n

onset

Remobi

liz

ati

on

at

rain

n+1

Longer rain interruption

Dryer matrix

Shorter rain interruption

Wetter matrix

3

1

2

4

Water in

matrix

Flow cytometry

Autochtonou s soil particle

FL 1 [a.u.]

FL

2

[a

.u

.]

0 5 10 15 20 25 30 35 40 1 10 100 1000 104 n a tu ra l s o il p a rti c le m o b il iza ti o n (m g )

Rain interruption duration (h) 50 60 70 80 90 100 m ic ro s p h e re r e te n ti o n (% )

5- Microspheres are eluted adsorbed to

soil colloids

0

10

20

30

40

50

%

M

ic

ros

pheres

ads

orbed

t

o

s

oil

c

olloids

n n+1 n+2

0

0,5

1

1,5

1

100

1

100

1

100

Duration of rain interruption before rain n (h)

R

ec

ov

ery

(%

of

injec

ted

)

microsphere

retention

(% injected)

natural soil

particle

mobilization

(mg)

n+1 n+2