Carbon and nitrogen dynamics after destruction of a 6-year-old perennial bioenergy crop
Résumé
Production of bioenergy from perennial crops is promoted within the context of energy transition. Switchgrass is a promising crop because of its high biomass production and low nutrient needs. The environmental balance of this perennial crop during its life has been shown to be more favourable than of annual bioenergy crops. However the impact of its destruction on biogeochemical cycles has not yet been investigated. Our aim was to provide insight in C and N dynamics after the destruction of switchgrass relative to a control treatment.
In this study we compare two treatments of an ongoing long term experiment initiated in 2010 in northern France: switchgrass (harvested yearly, 6-year-old) and an annual crop rotation (pea, rapeseed, wheat, barley, maize, wheat). Crop residues were sampled after switchgrass harvest in October 2015 and soil cores (0-60 cm) were extracted to quantify soil organic C and N stocks and belowground biomass. Switchgrass was tilled early November and both treatments were mouldboard ploughed early December. The monitoring of C and N fluxes started after switchgrass destruction in bare subplots and continued during 10 months. Soil CO2 and N2O emissions were measured continuously using automatic chambers and soil mineral nitrogen (SMN) was measured monthly (0-150 cm) to quantify net N mineralisation.
This study shows that the destruction of perennial crops modifies C and N dynamics, with possible consequences on subsequent crops and environmental impacts.
Format : Présentation
Origine : Fichiers produits par l'(les) auteur(s)
Licence : CC BY - Paternité
Origine : Fichiers produits par l'(les) auteur(s)
Licence : CC BY - Paternité