Concentrations of C and N were determined in the plant species in
both experiments in samples collected in 2012. Soybeans and the fall/
winter grain crops were sampled at harvest, while the cover crops
were sampled in fall/winter and spring crops at the pre-flowering
stage, i.e., before chemical desiccation. Samples comprised two
subsamples per subplot, collected with a 0.5 m  0.5 m frame. The
samples were dried in a forced-air oven at 65 C, ground and analyzed
for C and N concentrations using an elemental analyzer (LECO-
TruSpec1 CHNS). Samples from each plant species were mixed and
homogenized, and two samples were taken and analyzed for
cellulose, hemicellulose, and lignin (Silva and Queiroz, 2002). These
analyzes were not performed for the mixture of sorghum/ruzigrass.
The results are presented in Table 2.