Post-harvest residue input to cropland

Total annual input of carbon with crop residues to the soils in Missouri (North Central Region of the USA) was found to be about 3.7 t ha−1 for wheat, 3.4 t ha−1 for soybeans and 9.2 t ha−1 for corn. Root biomass represented 40–50% of total residues and its accumulation appears to be influenced by climatic conditions. Estimates of carbon outflow from the ecosystem in the form of CO2 were in good agreement with the biomass input.