New Holland CX720 Operator's Manual page 261

The area of loss is determined by the location of the
grain in relation to the combine. Each of these areas
must be checked to accurately determine which
combine adjustments (if any) can be made to reduce
the loss.
Grain on the ground in front of the combine head (1)
is defined as preharvest loss and is usually caused by
the weather. Determine the amount of this loss before
taking the combine into the field.
Grain found behind the head, but to the outside of the
drive tyres (2) is considered loss from the head.
These losses can be caused by improper head
adjustments or improper combine ground speed.
Grain on the ground directly beneath the combine (3)
is leakage. Holes in the auger bottoms and damaged
seals can result in large losses which are often
mistaken for shoe and straw walker losses (6).
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SECTION 3 – FIELD AND SITE OPERATION
Grain on the ground directly behind the combine and
the width of the shoe is caused by incorrect combine
adjustment(s), too high a ground speed, or leakage.
Shoe losses (4) can be caused by a build-up of
material on the top sieve which allows the grain to ride
out the back of the combine. This can be due to the
sieve opening being closed or opened too much, the
rear of the sieve raised too high (sieve angle too
extreme), or by a too low cleaning fan speed.
Losses (5) can also be caused by a cleaning fan
speed that is too high. The grain is then blown out of
the back of the combine.
An uneven loading of material on the top sieve can
also cause losses.
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