Soil Biophysical Structural Management Christian HARTMANN Pascal JOUQUET

Soil Bio-physical Structural Management Christian HARTMANN Pascal JOUQUET Michel GRIMALDI UMR BIOEMCO (becoming ‘IEES Paris’) Team ‘BIOPHYS’

Before explaining why we want to use biological activity to mange I would like to present the context: 1. our UMR : mixed research unit 2. our regional partnership in South-East Asia… UMR = a scientific question… i EES Paris

i EES Paris Biophys team Main focuses: In tropical landscapes subject to intense changes in land use 1. Describing biophysical processes that structure soil (aggregation vs. disaggregation) 2. Evaluating effects of changes in biophysical processes on soil ecosystem services (primary production; regulation of water fluxes and soil erosion; regulation of climate; …) Institute of Ecology and Environmental Sciences - Paris

i EES Paris Axis 1: Landscape and soil dynamics as a result of LAND-USE changes Field observations in long-term observatories • Drivers of land-use changes • Agricultural practices effects on: – vegetal cover diversity and fragmentation; – biodiversity of plants and soil fauna; – soil surface conditions: crusting, infiltrability, erodibility. Institute of Ecology and Environmental Sciences - Paris Biophys team

i EES Paris Biophys team Axis 2: Biophysical PROCESSES of SOIL structuration and resulting hydro-structural properties Field and laboratory experimentations Analysis of interactions between soil engineers (roots and macroinvertebrates) and soil composition, structure and hydrodynamic properties, at soil horizon and functional domains rhizosphere, drilosphere, …) scales. Institute of Ecology and Environmental Sciences - Paris Shrinkage curve

Laboratoire Géosciences Environnement Toulouse Et au sein de l’UMR on a un le groupe biophys…. Maintaing soil ressources… BIOEMCO; IRD makes the link with local partners that have the willing of improving the well being ofpeople

PARTNERSHIP ==> OUTCOME FOR THE COUNTRY Laos: NAFRI & NUOL Thailand: LDD & KKU - Knowledge transfer (academic research, lab, instruments…) - Well being of people and ressources of the country

IRD ==> partnership (national partners)

PARTNERSHIP ==> OUTCOME FOR THE COUNTRY - Knowledge transfer (academic research, lab, instruments…) - Well being of people and ressources of the country ==> SOIL RESSOURCES & FARMERS

WHY SOIL RESSOURCES? (and not food production for example…)

Soils…. A limited ressource, wisely developped…. through agriculture !

Big success for food production!

IN THE PAST 50 YEARS……. +200% Increments in the past 50 years Agricultura l production +117% World’s cultivated land +12% Irrigated area

High ecological and environmental cost…

Soil degradation status and trends • Soils of varying degradation status (low to high) show increasing degradation trends (GLADIS, 2011): – Water and wind erosion – Nutrient and SOM depletion – Acidification – Salinisation – Compaction – Contamination

SYSTEMS AT RISK (SOLAW) B - A series of land water systems now face the risk of progressive breakdown of their productive capacity (driven by demographic pressure and unsustainable

Till now, objective was food self sufficiency = studies mainly focused on optimizing crop yield (increase fertilizer, irrigation) ? Impact on groundwater quality ? From now, objective sould also be ‘maintaining soil ressources’…

Comparison pristine vs irrigated agriculture Chloride (mg/L) v Variations of 2 -3 orders of magnitude in Cl, NO 3 v How to explain such variations ?

Importance of soil type on Nitrogen balance Example of Turmerick (irrigated cash crop) Black soil Red soil (Vertisol) (Feralsol) Need to combine monitoring & modeling for understanding N behavior in soil = integrated approach What are the important parameters ? How to measure them at reasonable cost ?

Soils…. A limited, non-renewable, already degraded, …ressource.

What to do now? ? ? Change our practices: - avoid wasting, - increase recycling…

But most of the soils are already degraded…. . How to do the job? Using engineers! Soil and ecosystem engineers…

THE KEY SOIL ENGINEERS…

Some examples of Biogenic structures

Bioturbation by soil engineers Formation of biostructures: Biopores & Biogenic aggregates (galeries) (casts, mounds…) Modification of soil structure Hydrodynamic, SOM decomposition, nutrient cycling Ecosystem services Water infiltration, retention & quality Flood & erosion control Fertility & productivity Greenhouse gas emission

21 st century farmers have two options… First option:

THE KEY SOIL ENGINEERS… Second option:

And this is where Soil Bio-physical Structural Management (SBSM) becomes an INOVATIVE project… We want to link natural sciences with economic and social sciences….

After more than 100 yrs of intensification, 50 yrs of incredible success in food production for farmers, How to shift to soil ressource and environment management? They are economical factors, And even cultural factors….

Economical factors…. We are asking farmers to abandon a set of techniques that were efficient and take the risk of loosong everything….

Cultural factors…. We will lack of proteins…. And we know all risks associated with animal breeding… Eating insects is logical, and is also appreciated! But even cartesian westerners who do not take any risk will not easily consider insect as…

How to convince farmers ? ? But…. is this a relevant question? ? What kind of research would be useful for farmers, or at least take into account the farmers’ view point? But two tropical countries are different. .

This is why SBSM needed to be organised in India, to discover and learn from Indian experience… Experience in the labs and in the fields. Scientists know the natural processes, but we need to know also ‘agriculture’ and even ‘culture’…

Conclusion…. We have all skills in our own science. But solving practical, and necessary complex problems, we need to launch interdisciplinary researches, effectively interconnected with synergetic actions.

SBSM brings together people who have never worked together and who have complementary skills between natural and ‘human’ sciences…. The goal is to propose a draft of research project; it still is a challenge…. Thank you for your attention…