- Chewings fescue [Festuca rubra L. subsp. fallax (Thuill.) Nyman] is a desired
turfgrass with dense sod forming capabilities and superior shade tolerance. Thermal
residue management (open-field burning) has traditionally been used to remove post-harvest
residue and maintain seed yield over the life of the stand. However, alternative
non-thermal residue management practices have been observed to produce adequate
seed yields dependent upon cultivar.
Strong creeping red fescue (F. rubra L. subsp. rubra) is desired for
its prolific tillering capacity and creeping rhizomatous growth habit. In contrast to
Chewings fescue, maintenance of seed yield in strong creeping red fescue has only
been profitably produced under thermal residue management. Slender creeping red
fescue [F. rubra L. var. littoralis (Vasey)] is a desired turfgrass with a compact, less
rhizomatous growth habit, similar to Chewings fescue in desirable turf attributes.
However, little is known about the effects of post-harvest residue management in
slender creeping red fescue.
The objectives of this study were: 1) to evaluate seed yield and yield
components among different cultivars to thermal (open-burning), and non-thermal
(flail low and flail high) post-harvest residue management; 2) to evaluate harvest
index and percent cleanout to thermal and non-thermal residue management in
different cultivars; and 3) and to provide an economic analysis of thermal and non-thermal
residue management in all cultivars based on partial budgeting.
Three post-harvest residue management treatments (burn, flail low and flail
high) were applied over the course of two years. Seed yield components measured
included: total dry weight, fertile tiller number, spikelets per panicle, florets per
spikelet, and panicle length. Final seed yield in each cultivar and residue management
treatment method was determined after seed harvest and conditioning. Seed yield
component analysis was conducted over three production seasons.
Chewings fescue, strong creeping red fescue, and slender creeping red fescue
cultivars responded differently to residue management as indicated by a residue
management by cultivar interaction. In 2003 and 2004, residue management by
cultivar interactions were evident in seed number, seed weight, fertile tiller number,
percent cleanout, harvest index, and seed yield. Residue management by cultivar
interactions occurred in spikelets per panicle in 2003, whereas in 2004 a residue
management by cultivar interaction occurred in panicle length and florets per spikelet.
In 2004, non-thermal flail low, and thermal residue management resulted in
significantly greater spikelets per panicle in all cultivars. Thermal residue management
resulted in the greatest number of spikelets per panicle.
Results indicate that thermal residue management best maintained seed yield in
most subspecies and cultivars across both years. However, in 2003, non-thermal flail
low residue management produced profitable seed yield in only Marker slender
creeping red fescue. In contrast, thermal residue management resulted in poor seed
yields in Marker slender creeping red fescue and enhanced yields in Seabreeze slender
creeping red fescue in 2003. However, following the second year of thermal treatment
in 2004, Marker and Seabreeze both had lower seed yields, thus exhibiting the only
negative impact of thermal management among the cultivars tested in this study.
Moreover, upon review of an economic analysis, Marker slender red fescue was the
only cultivar that produced a positive net return of $78 and $4 ha⁻¹ under non-thermal
residue management in 2003 and 2004, respectively. Furthermore, in 2003, thermal
residue management net return increases ranged from $104 ha⁻¹ to -$996 ha⁻¹ in
Barnica and Shademark, respectively. In 2004, thermal residue management net return
increases ranged from $115 ha⁻¹ and $1,332 ha⁻¹ in Seabreeze and Shademark,
Poor seed yields were observed in all strong creeping red fescue cultivars
under non-thermal residue management across both years of the study. This may be
attributed to an observed reduction in fertile tiller number and seed yield. In addition,
percent seed cleanout was increased with non-thermal residue management. In 2004,
as stand age increased, thermal residue management resulted in greater seed yields in
all cultivars and species, except both cultivars of slender creeping red fescue. Thus,
this study provided substantial evidence that thermal residue management has the
potential to maintain or increase fine fescue seed yield as stands age as well as to
maintain stand profitability.