INFLUENCE OF CORN (ZEA MAYS L.) CULTIVAR DEVELOPMENT ON RESIDUE PRODUCTION

The amount and composition of crop residues added to soil in agroecosystems can influence decomposition processes and soil organic matter levels. This study aimed to evaluate residues (quantity and quality) of different corn cultivars commonly used in Brazilian cropping systems. The experiment was conducted for two seasons (2005/2006 and 2006/2007) in Rolandia, Parana State, Brazil. Ten corn cultivars that represent five degrees of breeding development (i.e., landrace, commercial variety, double cross, triple cross, and single cross hybrids) were evaluated. At harvest, carbon (C) and nitrogen (N) of non-yield residue and grain were determined. Except for grain C, other measures (grain N concentration, residue C and N concentration, and C: N ratio) varied among cultivars. In general, the hybrids had higher residue C and lower residue N concentrations than the landraces and commercial varieties. Findings suggest that breeding selection may have altered residue production and composition, which may influence soil C dynamics.