• Recous, Sylvie
• Ferchaud, Fabien
• Houot, Sabine

Abstract

The uses of organic resources (plant biomasses, organic wastes) for bioenergy in substitution for fossil carbon, impact biogeochemical cycles of agroecosystems in multiple ways: first through cultural practices implemented during the biomass production phase, but also linked to the pathway of biomass use. These effects are illustrated here through three examples: the impact of the choice of the plant species (annual, pluriannual, perennial) on water use and soil carbon balance; (2) the effects of harvest date scenario of miscanthus crop, an herbaceous perennial species, on the recycling of nitrogen and carbon in the plant, and the fertilizer needs; these two examples are taken from field trials of the INRAS. Recous et al. 42 Innovations Agronomiques 54 (2016), 41-58 “biomass and environment” experimental platform of Estrées-Mons (northern France); (3) the introduction of anaerobic digestion at the farm level and the subsequent impacts on the carbon balance and biogeochemical nitrogen cycle in soils. These examples show the difficulty to know and master all the practices and factors involved in the production or processing of organic resources to minimize environmental impacts, due to the multiplicity of effects, often antagonistic, on biogeochemical processes and fluxes. The study of these impacts on a time scale larger than that of a growing season (scale of the rotation, and long-term), and with a territorial dimension (location of the organic resource, soil types), is essential.

Topics

• impedance spectroscopy
• Carbon
• phase
• laser emission spectroscopy
• Nitrogen