Figure : Organic Waste Product (OWP) amended on QualiAgro

(DVB - composted sludge and green waste, "Biodéchets" - composted biowaste, OMR - composted household waste, "Fumier" - bovine manure)

Organic Waste Product (OWP) had been implemented previously by the team of Sabine Houot, and refers to all organic waste materials that can be applied in agriculture in the raw state or treated.

The use of OWPs in agriculture has an agronomic interest because it improves soil fertility. It also has economic and environmental benefits because recycling waste creates a relatively inexpensive product that contains nutrients necessary for crops and that can therefore be substituted to mineral fertilizers whose synthesis consumes a lot of fossil energy.

Soil fertility is based on 3 properties:

• Chemical: availability of nutrients, adequate pH for crop growth (around 7), ability to retain nutrient cations ...,
• Physical: stability, erosion, roots anchoring, plants water supply, resistance to settlement ...,
• Biological: microorganisms, macrofauna

OWPs can theoretically contribute to the maintenance and even increase organic matter (OM) stocks in soils, and consequently modify their physical, chemical and biological properties.

However, the agronomic effects expected and observed in the field may be difficult to control given the great variability of the applied OWPs, their management methods, their treatments and spreading practices. It is therefore necessary to apprehend in the short, medium and long terms the agronomic values ​​of the applied OWPs but also to estimate the potential impacts and risks. Indeed, despite the benefits provided by the spreading of OWP, these can have harmful environmental impacts and can also be sources of contaminants (pathogens, organic or inorganic chemical contaminants).

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