The amount of crop residue
added per pot (9.4 g for rye or 10.1 g for
sunnhemp) was based on observed field biomass
production of 7.6 Mgha–1 (Schomberg
et al., 2006) and 8.1 Mgha–1 for rye and sunnhemp, respectively. The goal
was to provide a concentration of the residue
similar to what would be provided by the
cover crop under field conditions. The concentrations
(by weight) of the ground dried residues in the soil mixture were 1.5% and
1.6% for rye and sunnhemp, respectively.