Effect of crop residue harvest on long-term crop yield, soil erosion and nutrient balance: trade-offs for a sustainable bioenergy feedstock

Abstract

Background: Agricultural residues could potentially be converted to bioenergy, but the sustainable harvest rate is unclear. Results: Residue removal increases soil loss at rates that vary with topography, crop rotation and management; decreases yields (100-year mean yields changed -0.07 to -0.08% for every percent of residue mass removed); decreases soil carbon (approximately 40–90 kg C ha-1 year-1 per Mg of residue harvested); and decreases soil nitrogen (∼3 kg N ha-1 year-1 per Mg residue harvested). Conclusion: Even where soil loss is within tolerable limits, harvesting residue is a question of trade-offs in terms of reduction of yield and loss of soil nutrients. The effects of increased residue harvest are highly variable, depending on local climate and soil erodibility and it is thus problematic to apply a single harvest rate globally. However, on flat land under conservation management, the majority of residue could be sustainably harvested for bioenergy.