The effect of residue removal and burning on the growth of Festuca longifolia Thuill. and Festuca rubra L. subsp. commutata Gaud. established for seed production

Graduation date: 1987Hard Fescue (Festuca longifolia Thuill.) has potential for in\ud creased turf use but does not respond well to normal seed production\ud management practices in Oregon. Field burning (the normal residue\ud management practice) results in reduced seed yields in commercial hard\ud fescue seed production fields but stimulates seed production in Chewings\ud fescue (Festuca rubra L. subsp. commutata Gaud.) and other species. The purpose of this study was to describe differences in\ud tillering patterns in hard fescue and Chewings fescue in response to\ud various post harvest residue management treatments.\ud Burn and crewcut (clip and vacuum) post harvest residue management treatments were applied on two different dates. Information on\ud number and type of tiller units and tillers produced, dry weights,\ud leaf number and length, tiller fertility and components of yield was\ud collected through one seed production season.\ud Differences in hard and Chewings fescue were indicated by cultivar\ud x management interactions in many of the components measured.\ud Chewings fescue has the ability to recover from all but the most severe (late burn) management by November while tiller numbers were\ud reduced in all but the least severe (early crewcut) management in hard\ud fescue on that date.\ud Differences were also observed in the type of tiller produced.\ud Hard fescue produced a higher percentage of aerial tillers than did\ud the Chewings fescue. These aerial tillers did not survive beyond\ud February and made no apparent contribution to yield. No differences\ud were observed in the number of early season basal tillers. A high\ud vegetative tiller population was maintained in hard fescue until\ud harvest while in Chewings fescue dry matter production was concentrated in fertile tillers.\ud The superior seed yield of the Chewings fescue cultivar was due\ud to a 30% greater number of fertile tillers per unit area and a 25%\ud greater mean seed weight. Differences in seed yield between species\ud cannot be simply attributed to the availability of early season basal\ud tillers for floral induction but are due to the effects of intertiller\ud competition, dry matter partitioning and the genetic propensity\ud to favor seed production over the maintenance of vegetative tillers.\ud In this study, normal (early) burning did not reduce the seed\ud yield of the hard fescue cultivars. This was attributed to the pretreatment\ud flail chop and partial removal of harvest litter. This\ud suggests that a modified burn management system may increase or main\ud tain hard fescue seed yield