Unlock P with roots ? E. Le Cadre Montpellier SupAgro Joint Unit Research « Functional ecology & Biogeochemistry of Soils & Agro‐ecosystems » www.facebook/ecosols (in french) http://www6.montpellier.inra.fr/ecosols_eng/ (in english)
POSITIONNEMENT DE LA RECHERCHE Agriculture et demande alimentaire mondiale
How ?
Bloom algaux de M.aeruginosa, Lac Erié, USA Sutton et al 2011, Nature
Pollution
Géopolitique Raréfaction des ressources
Rapport FAO,
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Fertilizers
Bloom algaux de M.aeruginosa, Lac Erié, USA Pollution and Biodiversity loss (Payne et al, 2013)
Some raw materials are finite and non evenly distributed (Cordell et al, 2009, Withers et al, 2014)
« Too much of a good thing » Soil quality degradation (Cassman, 1999; Lal et al, 2006) (Sutton et al 2011, Nature)
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POSITIONNEMENT DE LA RECHERCHE Agriculture et demande alimentaire mondiale Bloom algaux de M.aeruginosa, Lac Erié, USA Sutton et al 2011, Nature
Pollution
Agro ecological transition
Géopolitique
Raréfaction des ressources
Rapport FAO,
Which solutions for P fertilization in agroecolo ? Close the biogeochemical cycles (waste and livestock recycling, nitrogen fixation, …)
Plant sciences Soil quality
Use legacy soil ressources
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Use biological activities rather than fertilizers
residusphere Photo M. Bravin, CIRAD (Rhizotest)
drilosphere
Photo : SIMBIOS, Aberdeen, UK
rhizosphere
Soil aggregates
SOL Mineral forms
Organic forms
Use biological activities rather than fertilizers Environmental availability
Total concentration in soils
soil – solution interactions
soil
Potentially available concentration
Environmental
bioavailability
Bioavailability
rhizosphere absorption membrane
plant (root)
Adapted from Harmsen et al. 2007. Measuring bioavailability: from a scientific approach to standard methods. J Environ Qual. 2007 31;36(5):1420‐1428.
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Use biological activities rather than fertilizers
P-H2O (µg kg-1) 140 120
Chromic Cambisol
Mesuré * +60% 80 Mesuré Simulé
100
60
40 20 0
NO3-
« Bulk soil »
Rhizosphere Rhizosphère
Rhizosphere
Devau N, Le Cadre E, Hinsinger P, Gérard F. 2010. Ann. Bot., 1183‐1197
ANR Perfcom Peuplements complexes Performants en agriculture bas intrants – Interaction multitrophique et facilitation intergénotypique
Soil P is a treasure and roots the thieves ? RHIZOSPHERE and roots 100 µm
(Source : Jaillard and Hinsinger, 1993).
(Source : : Margaret E. Mc Cully) (Photo: Margaret E. McCully, Dpt Plant Biology, Biology, Carleton University, Canada)
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5
Soil P is a treasure and roots the thieves ? RHIZOSPHERE and roots 100 µm
Chemistry Physics Biology (Source : Jaillard and Hinsinger, 1993).
(Source : : Margaret E. Mc Cully) (Photo: Margaret E. McCully, Dpt Plant Biology, Biology, Carleton University, Canada)
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Soil P is a treasure and roots the thieves ?
Distance from roots (mm)
Jones DL, Hodge A. Kuzyakov Y. 2004. Plant and Mycorrhizal regulation of rhizodeposition. New Phytologist. 163: 459‐480
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Soil P is a treasure and roots the thieves ? Plant internal demand
Factors influencing P uptake
Root architecture biomass
Root activity Source: Jaillard and Hinisnger, 1993
(Source : Jaillard and Hinsinger, 1993).
Pagès et al., 2004 13
Soil P is a treasure and roots the thieves ? Plant internal demand Root architecture biomass
Root activity
Shen J., Yuan L., Zhang J., Li H., Bai Z., Chen X., Zhang W., Zhang F. 2011. Update on phosphorus Dynamics in the soil‐plant Contiunum. Plant Physiol. 156, 997‐1005.
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Soil P is a treasure and roots the thieves ? Plant internal demand Root architecture biomass
Root activity (Source : Jaillard and Hinsinger, 1993).
Richardson AE, Barea JM, McNeill A., Pringent‐Combaret C. 2009. Plant Soil 321: 305‐339
Soil P is a treasure and roots the thieves ?
Net exsudation of protons (mmol Kg‐1 de sol)
. Soil pH
OH ‐
Distance par rapport à la racine (mm)
H+
NO3‐
300 mg N Kg‐1 100 mg N Kg‐1
NH4+
300 mg N Kg‐1 100 mg N Kg‐1
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Soil P is a treasure and roots the thieves ? . Soil pH P-H2O (µg kg-1) 800
Experiments
Chromic Cambisol
600
pH initial Acide
Luvisol
Base
400
pH init. 200
MODELISATION (visual Mineteq)
0 3
4
5
6
pH du sol
7
9
8
Devau N, Hinsinger P, Le Cadre E, Colomb B, Gérard F. 2011. Geochim. Cosmo. Acta, 2980‐2996 Devau N, Le Cadre E, Hinsinger P, Jaillard B, Gérard F. 2009. Appl. Geochemistry, 2163‐2174
ANR Perfcom Peuplements complexes Performants en agriculture bas intrants – Interaction multitrophique et facilitation intergénotypique
Soil P is a treasure and roots the thieves ? Adsorbed P (mg kg-1) 100 80
. Soil pH
Chromic Cambisol Oxydes Fe
Illite
Kaolinite
60
¾ Control of P availability by soil minerals and especially clays
40 20 0 4
5
6
Soil pH
Adsorbed P (mg 100 80
7
8
9
kg-1)
Adsorbed P (mg kg-1) 100
LuvisolP-
60
60
40
40
20
20
0
LuvisolP+
80
4
5
6
7
Soil pH
8
9
0 4
5
6
Soil pH
7
8
9
Devau N, Hinsinger P, Le Cadre E, Colomb B, Gérard F. 2011. Geochim. Cosmo. Acta, 2980‐2996 Devau N, Le Cadre E, Hinsinger P, Jaillard B, Gérard F. 2009. Appl. Geochemistry, 2163‐2174
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Soil P is a treasure and roots the thieves ? . Soil trophic relationships
myo‐inositol hexakis‐phosphate (phytate) Up to 80% of soil organic P P
P
P P
P
P
P
P
P
P
Specialized enzymes
P
P
Phytases
Plassard C. 2015. PSP5 conference, Montpellier, France ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
Soil P is a treasure and roots the thieves ?
Research question: What is the role of bacteria in phytate-P cycling ?
. Soil trophic relationships Plant shoot Plant root Phytase release
Mycorrhiza Uptake
Soil Phytate
Free Pi Mineralization
Plassard C. 2015. PSP5 conference, Montpellier, France ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
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Soil P is a treasure and roots the thieves ?
Research question: What is the role of bacteria in phytate-P cycling ?
. Soil trophic relationships Plant shoot Phytate mineralizing Bacteria
Plant root Mycorrhiza
Immobilization
Uptake
Soil Phytate
Free Pi Mineralization P P
P P P
P P
P Plassard C. 2015. PSP5 conference, Montpellier, France
ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
Soil P is a treasure and roots the thieves ?
Research question: What is the role of bacteria in phytate-P cycling ?
. Soil trophic relationships Plant shoot Phytate mineralizing Bacteria
Plant root Immobilization
Mycorrhiza Uptake
Soil Phytate
Free Pi Mineralization
The new question is : how to unlock the bacterial P ? Plassard C. 2015. PSP5 conference, Montpellier, France ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
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Soil P is a treasure and roots the thieves ?
Hypothesis: Role of trophic relationships?
. Soil trophic relationships ¾ Microfauna such as protozoa and nematodes are living in soils ¾ Populations of nematodes in soils = the most abundant organisms Bacterial‐feeders
Fungal‐feeders
Predatory nematodes
Omnivores
Root‐feeders Plassard C. 2015. PSP5 conference, Montpellier, France ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
Soil P is a treasure and roots the thieves ?
Hypothesis: Role of trophic relationships via bacterial grazing
. Soil trophic relationships Grazers
Plant shoot
Phytate mineralizing Bacteria
Plant root Mycorrhiza
Immobilization
Uptake
Soil Phytate
Free Pi Mineralization P P
P P P
P P
P
Plassard C. 2015. PSP5 conference, Montpellier, France ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
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Soil P is a treasure and roots the thieves ? . Soil trophic relationships Same biological partners: P. pinaster +/‐ H. cylindrosporum +/‐ Bacteria (Bacillus subtilis) +/‐ Bacterial feeding nematodes
Culture conditions: Two P sources ‐ Soluble P (KH2PO4 3 mM) ‐ Phytate 1 mM 100 days of culture Plassard C. 2015. PSP5 conference, Montpellier, France ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
Soil P is a treasure and roots the thieves ?
Net Plant P accumulation (mg plant-1)
. Soil trophic relationships Soluble P 1.2
Phytate
None Bact N+Bact
Expt 1 Expt 1
0.8
a
a
a
a
a a a a
b X 3.5
0.4
X 2.7
c
d d 0.0 NM plants
M plants
NM plants
M plants
With nematodes total plant P accumulation from phytate (+ 0.8 mg P) is very close to that in mineral P Plassard C. 2015. PSP5 conference, Montpellier, France ANR BLANC Unlock P: Mobilisation of soil phytate : what are the keys to unlock phosphorus from this treasure ?
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Conclusions : Unlock P in action(s)
1. Cropping systems
Photo ANR Perfcom, INRA Coord. P. Hinsinger
Philippe Hinsinger et al. Plant Physiol. 2011. 156:1078-1086
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2. New innovative fertilizer to use soil P legacy Nanobiotechnologies
Ghormade et al, 2011 in Biotech. Adv.
Withers et al, 2014 in Env. Sci. Tech.
« Manipulating extracellular enzyme activities for ecosystem services » Burns et al, 2013 in Soil Biol. Biochem.
2. New innovative fertilizer to use soil P legacy P (μmoles P / plante) 16 14 12 10 8 6 4 2 0 Control
Nanofertilizers
Trouillefou C, Le Cadre E, Cacciaguerra T, Cunin F, Plassard C, Belamie E. 2014. J. Sol‐Gel Technol. + 1 Patent
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3. A new genotype selection
Krasilnikoff et al. 2003. Variation in phosphorus uptake efficiency by genotypes of cowpea (Vigna Unguiculata) due to differences in root and root hair length and induced rhizosphere processes. Plant Soil. 251: 83‐91.
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