The Rural Voice, 1999-06, Page 50services of the Pest Diagnostic
Clinic.0
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Nutrient deficiency
symptoms in wheat
By Keith Reid
Soil Fertility Specialist, Walkerton
If your wheat is off-colour, it is
worthwhile to figure out what is
causing the discolouration. It may be
possible to take corrective action this
year, or it may point to something
that should be corrected for next
year's crop.
The most common symptom seen
in wheat fields is yellowing of the
leaves. The first thought in most
cases is that this is nitrogen
deficiency, and this may very well be
correct. but there are other possible
causes for yellow leaves.
Nitrogen deficiency will show up
in the older leaves first, as nitrogen is
pulled out of mature tissue to supply
the new leaves and the growing point.
The yellowing will start at the tip of
the leaves and proceed down the
leaves as the deficiency becomes
more severe. Nitrogen deficiency can
be caused by uneven fertilizer
application (which means part of the
field has received excess N, and will
be at risk of lodging), or losses df
nitrogen through leaching (on coarse
textured soils) or denitrification (on
waterlogged soils).
Yellow wheat which is standing in
water, is not likely deficient_ in
nutrients. The yellow colour is a
response to ethylene, released by the
plant when it is suffering from lack of
oxygen to the roots. These plants
should recover once the soil dries,
unless there has been denitrification
losses.
In rare cases, potassium deficiency
will show up on wheat growing in
coarse, sandy soils. The yellowing
will show up on the older leaves,
similar to nitrogen, but it begins as a
uniform yellowing of the older
leaves, proceeding into bronzing or
scorching along the leaf margins. A
soil test will quickly tell whether
potassium is in adequate supply.
Sulphur deficiency is unlikely to
occur in Southern Ontario because of
the supply of sulphur in acid rain. If it
46 THE RURAL VOICE
Advice
did occur, you would see a general
yellowing of the whole plant, similar
to nitrogen but not confined to the
lower part of the plant.
Manganese deficiency is the other
cause of yellowing in the field, but it
is much harder to pin down specific
deficiency symptoms. Most often,
there will be patches in the field
showing a general pale colour of
yellowing, and stunting.
Occasionally, there will be gray -
white specks or spots on the lower
leaves. The pattern of affected areas
in the field is often most diagnostic.
Manganese can be deficient in highly
alkaline soils, particularly when
combined with low organic matter,
and in soils with very high organic
matter. Manganese has increased
solubility in soils with reduced
oxygen content, so mild compaction
can cause a manganese deficiency to
disappear. If you see the tire tracks
from the floater truck turn green,
while the rest of the field turns
yellow, it is an almost sure bet that
manganese is the problem. A foliar
application of 8 kg/ha of manganese
sulphate (2 kg Mn/ha) is the most
effective way to correct the
deficiency. If you are not sure,
another quick diagnostic test is to mix
a little manganese sulphate in a spray
bottle, and spray it on a small patch
of wheat. If manganese deficiency is
the problem, the sprayed patch will
green up within a day.
Of course, insects or diseases can
also cause yellow wheat, so don't
overlook them as possible problems!0
Custom raising
dairy heifers
By Joel Bagg
Agriculture & Rural
Representative, OMAFRA
Custom raising dairy heifers is not
a common practice in Ontario, but
does offer potential advantages to
some owners and custom feeders.
There is an increasing interest due to
the currently higher prices for
replacement and ET recipient heifers.
Custom feeders can. create a
business opportunity, market their
forage and grain crops, utilize
existing facilities and use specialized
heifer -raising management
techniques. Dairy producers can
benefit by decreasing their
requirements for feed, facilities, and
labour, and increase the time devoted
to milking herd management. A risk
for both parties is the increased
potential for disease transfer due to
mixing animals from more than one
farm. This risk must be minimized by
proper management.
Most agreements are based on a
daily charge per head per day. Rates
charged vary considerably, but $ 1.50
to $2 per head per day is typical. It is
not uncommon to have different rates
for different ages, such as $ 1.65
under a year old and $1.85 over a
year old.
Other agreements are based on per
pound of gain, or feed costs plus
yardage. Usually rates include feed,
bedding, routine health care, labour
and housing. Semen, vaccines, hoof
trimming and specialized health
needs are billed as extras. Custom
operators should budget their costs
carefully to ensure an adequate return
to labour and management, while still
remaining competitive.
A written agreement should be
used for the protection of both the
owner and the custom feeder. "Who
is responsible for what" must be
clearly understood by both parties. -
Agreements could specify growth
guidelines, health care, nutrition,
bedding, heat detection, breeding,
insurance, death loss and payment
arrangements. The fact sheets "Guide
To Developing A Custom Dairy
Heifer Raising Agreement" and
"Considerations For Custom Raising
Dairy Heifers" are available by
contacting the Ontario Ministry of
Agriculture Food and Rural Affairs,
Fergus Office at 519-846-0941 or 1-
800-265-8332.0
Getting credit for
small business
By Dael Bierworth
OMAFRA Business Management
Advisor, Markdale
Small business is the fastest
growing sector of our economy,
providing employment and profits for
owners and investors. Lending