Em4885 irrigation management practices to protect ground water

4 CHAPTER
IP 3.02.07 - Develop Realistic Yield Goals
Objective
Reduce overapplication of fertilizer to produce yields that are either not attainable
or not economical.
Description
Adequate fertilizer is just one part of a successful cropping program. Given that enough
nutrients are available to the crop there may be other “weak links” in the program that
will limit yields. These include the insect control program, irrigation management,
field preparation, harvest procedures, and handling of the crop after harvest. If these
components cannot be improved, make sure that excess fertilizer is not being applied
uselessly. Also, maximizing yields may not maximize farm income as increased inputs
may not pay for themselves in enough increased yields.
Bonneville Power Administration publication DOE/BP-21925-11, Optimum Energy
Efficiency, (published February 1988), addresses the question of net returns to the acre
at various production levels from the standpoint of energy usage.
SECTION 3 - APPLY FERTILIZER PROPERLY
(NOTE APPLICABLE WAC REQUIREMENTS)
IP 3.03.01 - Calibrate Application Equipment Including Manure
Spreaders to Apply the Proper and Known Amount
Objective
Make sure that the exact amount desired is applied.
Description
The application equipment should be calibrated to apply a known amount of fertilizer
uniformly across the equipment’s application path. Most application equipment comes
with instructions and calibration charts from the manufacturer. However, for accuracy,
testing should be done in the field.
This Practice is also applicable to manure spreaders. Manuring should be viewed as a
fertilization technique as well as manure disposal. Manure should be tested for fertilizer
content as per IP 3.02.04. Knowing how much is being applied with the manure spreader
will indicate how much fertilizer, especially nitrogen, is being applied with the manure.
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