Producing Quality Oat Hay

Knife versus disc cutters
There is always great discussion over the virtues
of disc and knife cutting machinery. Disc cutters
have a greater cutting capacity than knife cutters
and can be operated at greater speeds. Working
speeds for disc cutters are stated as 20 to 30%
higher than knife cutters, which can convert into
cutting time efficiencies. This is often the reason
for their widespread use. However, excess speed
is one of the most common reasons for poor
cutting and windrow presentation with both types
of cutters.
Image 7.3 Disc cutters have a greater cutting capacity than
knife cutters and can be operated at faster speeds.
Disc cutters produce excellent results providing
cutting blades are sharp and working speeds are
not excessive (8 to 12 km/hr) for crops of 7 to
10 tonnes per hectare. Some operators have a
preference for disc cutters when cutting lodged
crops, because the discs have a lifting action on
the cut hay. This may be an advantage but can
result in variable cutting height depending on the
direction of travel and the direction the crop is
leaning. The best direction of travel in lodged
crops often is determined by trial and error.
Knife cutters must be sharp and when they are
driven at moderate speeds the cut and windrow
formation is excellent. Operating speed is
particularly important in lodged crops where
poor results are the most obvious.
PRODUCING QUALITY OAT HAY
Rotary or flail slashers
Flail slashers are not used to cut cereal hay
and while rotary slashers can be used the
performance thus far has been inferior to disc or
knife mowers. The cut hay is not conditioned
and windrow presentation can be poor.
Windrowers
Windrowers are a compromise for hay cutting, as
they do not condition hay. They are most suited
to cutting straw after grain has been harvested.
Windrowers are sometimes used when hay yields
are low and the extra width of a windrower is
utilised to produce a windrow of suitable size for
baling. Windrowers have high capacity but as hay
is cut onto a belt front and deposited either into
the centre (central discharge draper fronts) or on
one side (honeybee front) the cut stems of hay
are usually predominantly presented lying in the
same direction as cutting. This can result in more
hay falling between the cut stalks and contacting
the soil surface, making it difficult for super
conditioner or baler pick-ups to retrieve all the
cut material. Even if hay remains supported on
the cut stems the direction in which the cut
stems are leaning can make pick up difficult by a
normal baler pick-up. Raking windrows or the
use of mixing belts can help overcome this
problem but invariably produces inferior
windrows to those produced by a mower
conditioner. As windrowed hay is not
conditioned at cutting it takes longer to cure.
All in one mower conditioner/
super conditioners
All in one mower conditioners/super
conditioners are a relatively new innovation and
are still being developed and commercialised.
They execute two operations in one, reducing
the number of passes required to convert the
standing crop to curing hay.
Evidence so far shows these machines to be very
good when soil and atmospheric moisture are
low (dry springs or late cuts), as hay is rapidly cut
and cured in one pass. However, cutting lush
crops with an all-in-one machine when the soil
surface is moist and humidity is high, can create
dense windrows and promote mould formation.
In this situation additional removal of free
moisture from the crop by raking, tedding or
super conditioning may be required.
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