50 Years of contrasted residue management in an agricultural crop: impacts on the soil carbon budget and on heterotrophic respiration.

This study aims to estimate the carbon (C) loss by soil heterotrophic respiration (SHR) in three contrasted residue management treatments (Residue Export, Farm Yard Manure addition and Residue Restitution after harvest) through the establishment of soil C budgets, and to compare these estimations with field SHR measurements.
The soil C budgets were calculated in each case on the basis of total soil organic C content and C input data compiled since the beginning of the experiment in Belgium, 50 years ago. SHR fluxes were measured in 2010 and 2011 to compare them with the budget-based estimates and to assess SHR sensitivity to temperature. The comparison suggested that the treatment receiving the largest C input does not necessarily sequestrate the most C or produce the largest CO2 fluxes.