Agricultural Valorization of Organic Waste Products
What are the benefits of organic product (OR) recycling?
Today 300 million tons of OR are yearly produced in France coming from agriculture (animal manures), urban activities (sludge, urban composts) and industries (agro-industries or other). The recycling in agriculture is largely encouraged due to their contents in nutrients and organic matter contributing to the closing of biogeochemical cycles in territories. Additionally, anaerobic digestion is encouraged to produce alternative sources of energy and fertilizer, and OR recycling could also contribute to increase of the organic C stocks in soils and therefore attenuate greenhouse gaz (GHG) emissions from anthropogenic sources.
What are the risks ?
However, these recycling practices may also have environmental impacts related to nutrient management such as risks of nitrate leaching of emissions of N2O and NH3. Inputs of OR to soils can also represent a source of contaminants contained in OR (organic contaminants such as pharmaceuticals, persistent contaminants…, trace elements, pathogens…).
Needs for field observations and measurements
Both benefits and environmental impacts may vary with the origin and characteristics of the OR, the pedoclimatic conditions. On the other hand, the actual regulations about recycling may be adequate to prevent ecosystem alteration and questions remains on the long-term effect of repeated applications. It is thus of great importance to know and quantify these benefits and the potential impacts in representative field conditions.
In that respect, the French Observatory on Organic Residues, the SOERE PRO, has been created to study the agronomic effects and the potential risks of the recycling of the OR in various agricultural situations.
See => Observatory presentation