Cool-Season Perennial Grasses for the
Will C. Cradduck –
Dr. Andy Hopkins – Noble Foundation, Inc.
Grasses that are productive, well adapted, and tested on the southern
Rationale.
Grasses included in this
study are for the most part not native grasses to the southern
Thus, objectives of study are to will determine effects of spring and autumn grazing vs. a non-grazed, hay harvested treatment of different cool-season perennial grass species and cultivars on persistence, quality, mineral concentration, and biomass production. Please see the end of this summary for a plot map and list of grass species and cultivars.
Methods.
Eighteen
cultivars and advanced breeding lines were planted near
Results.
Persistence.
For stand counts, 100% stand
represents at least 1 live plant for every 8 inch x 8 inch area of the plot (
Although it is unlikely for the stand counts to increase once the stands are established, these graphs occasionally show an increase. This is probably due to increases in size of the individual plants as they mature, and some error in sampling. Increases in stand counts in the western wheatgrass plots are due to prolific rhizomes filling in any empty spaces.
The extensive rhizome production of all four western wheatgrasses included in this study have eliminated any recognition of the original seeded rows. These grasses are spreading to adjacent plots, and are beginning to be a problem. This rhizome production may lend itself to tolerance of high grazing pressures, as it may allow the plant many points of regrowth protected beneath the soil surface. They also show little drip tape effect as is evident in the other plots, possibly also due to extensive rhizomes and transport of water and nutrients. The western wheatgrasses also maintained a green color through the dry summer of 2003 when the other grasses were basically dormant.
Some of the tall fescue stand counts and all of the smooth brome stand counts appear to be slightly less in the grazed than non-grazed areas. However, all stand counts are still above 95%, and the difference in grazed and ungrazed is probably not biologically significant. It may only be an artifact of reduced crown and/or overall plant size due to grazing, and not a difference in persistence. Thus far, all grasses have demonstrated excellent persistence under both grazing and hay cutting management.
Forage Quality.
Determination of forage quality indicators are in progress.
Forage Minerals.
Determination of forage mineral concentrations are in progress.
Canopy Height.
Canopy height was measured by the disk meter method. Canopy heights are a good indicator of animal grazing patterns, as well as seasonal growth patterns.
In spring 2003, steers grazed plots
fairly uniformly with the exception of the tall and western wheatgrasses. The steers appeared to find them relatively
unpalatable, and we could not force them to graze these plots without
overgrazing the other plots. During the
autumn grazing period from November
Growth patterns over the year were similar for these grasses, although actual amounts differed. Following is a graph of forage productivity of these cool season grasses over one year, based on growth documented by canopy height measurement. This graph is based on the haycut portion of the plots.
Biomass Production.
Haycut yields were calculated by clipping a sample of the forage at a 2-inch cutting height. Each species and variety is harvested in spring based on growth stage rather than a common harvest date. Forages are harvested when 50% of the tillers reach the panicle emergence stage. In autumn, all grasses are harvested at a common date. Grazed areas are only harvested by spring and fall grazing with the exception of an occasional sample to document biomass. Ungrazed areas are harvested as for hay.
The spring 2003 haycut shows noticeably higher yields for the tall wheatgrasses, and noticeably smaller yields for the fescues. This is probably primarily due to the different harvest dates, as noted in the graph. Currently, it appears that these grasses are producing a larger percentage of their biomass in the autumn growth period, despite higher rainfall in the spring and less summer precipitation for the last few years. This year, that may have been affected by the fact that a lot of biomass was left on the plots over the summer and then harvested with the new growth in the autumn, possibly artificially increasing the fall hay harvest.
Early establishment
Visual ratings were used to document the early establishment phase. Smooth bromes and wheatgrasses were slower to establish, especially the western wheatgrasses, but all of the plots were initially well established, by the following autumn. Establishment time may be an important factor to many producers, so the quicker establishing grasses such as hardinggrass and fescue may be a better option assuming they measure up in other respects.
Based on these plots, if these grasses were planted in early autumn, producers might expect very limited forage production from the fescues and hardinggrasses the following spring. The wheatgrasses and bromes would only supply limited forage the following autumn. By spring of the second year, plants are mature enough to produce near their full capacity.
Conclusion.
Although this research is still in progress,
results to date suggest that many of these grasses show promise as viable
forage species on the southern
These grasses could fill gaps in available forage in both spring and autumn, where producers have generally relied on hand feeding and annual cereal crops. These grasses may allow livestock producers valuable options and flexibility when designing their grazing systems.