Alternative Residue Management and Stand Age Effects on Seed Quality in Cool-season Perennial Grasses

Field-burning based management of crop residue after seed harvest has been an important but controversial component of the production of cool-season perennial grass seed crops. On-farm trials were conducted in 26 commercial seed fields to examine the effect of residue management practices and stand age on seed quality. Species tested included: perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea Schreb.), Kentucky bluegrass (Poa pratensis L.), creeping red fescue (F. rubra L.), Chewings fescue (F. rubra spp. commutata Gaud.), orchardgrass (Dactylis glomerata L.), and dryland bentgrass (Agrostis castellana Boiss. and Reut.). Residue management treatments included: (i) flail chopping with no straw removal (Straw), (ii) removal of straw by baling with or without further management of stubble (Bale), (iii) removal of straw by baling, followed by propane burning (Propane), and (iv) open-field burning (Burn). Growing cool-season perennial grass seed crops without open-field burning did not reduce seed purity or germination. Straw management without removal in Chewings fescue decreased purity and caused reduced seed germination. Seed purity was lower in older stands of perennial ryegrass, but tended to be higher in older stands of tall fescue. Seed germination was not consistently related to age of crop stand. Reduced seed purity was often accompanied by increased inert matter and sometimes by lower seed germination. Cool-season perennial grass seed growers can generally adopt alternative residue management practices without compromising seed quality.