General principles Identify
clearly
the intended sward
use and select only recommended varieties capable of meeting those requirements. Always consider using
white clover to improve soil fertility or herbage quality and choose prostrate growing grazing-tolerant
varieties or tall growing higher yielding silage-tolerant varieties, as appropriate. Include tetraploid
perennial ryegrass varieties in all swards at a third of the total seed weight, except where poaching
may become a severe problem, to improve sward palatability and productivity.
Seeds
mixtures Correctly designed grass seeds mixtures can ensure consistently
high
performing swards with a flexibility and capacity to produce top quality forage at the time dictated
by the needs of the farming enterprise. In addition to yield potential and sward density, the selection
and matching of varieties for inclusion in a mixture should also involve consideration of such factors
as seasonal distribution of productivity, timing of maturity, growth habit, palatability and longevity
A wide range of different seeds mixtures are available in commerce which are designed to meet the individual
needs of most Northern Ireland grassland enterprises. However, to maximise production under difficult
conditions or for specific enterprises, special mixture formulations may be necessary. Information and
design of these special mixtures is available at all local Department of Agriculture and Rural Development
(DARD), Agricultural Development Centres.
Grazing
swards Try to use mixtures of either early and intermediate or intermediate
and late perennial ryegrass varieties designed for specific functions and use more complex mixtures
only where the intended sward use cannot be clearly identified. On free draining early ground, consider
including early Timothy, early perennial ryegrass and particularly early tetraploid varieties in the
mixture, supported by an appropriate fertiliser policy to produce valuable growth for spring grazing.
On heavy land include Timothy and dense growing late pasture type perennial ryegrass varieties and exclude
open growing grasses such as tetraploids, hybrids and Italians to produce tight swards resistant to
poaching.
Silage swards As
the
silage crop develops,
yield is rising but digestibility is falling, so avoid delaying cutting after the appearance of the
first seed heads in or below the top ‘flag’ leaf as digestibility will then begin falling very rapidly.
Decide when silage harvesting normally starts on the farm each year and select varieties from the maturity
group expected in most years to reach the 67D stage at that time. Sow either single varieties ("straights")
or simple mixtures of a few varieties of similar maturity to make the timing of the first silage cut
more easily determined. Some varieties produce a greater proportion of their potential yield during
the first two silage cuts, whereas others have a more even spread of production and so provide better
back-end grazing. To simplify silage timing management, select varieties for silage with as similar
a seasonal production pattern as possible.
