Em4885 irrigation management practices to protect ground water

IP 3.02.03 - Analyze Plant Tissue to Identify Nutrient Requirements
Objective
Reduce excess applications of fertilizer by obtaining more information on how much
is actually in the plant and needed.
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CHAPTER 4
Description
Plant tissue analyses can identify how much nutrient is actually in the plant. This will lead
to more accurate recommendations on further applications and can also serve as a guide to
all applications in succeeding crop years. As with soil sampling, proper procedures need to
be followed to ensure a representative sample of the field.
It is important to consider the crop, whether an annual or perennial, condition, and growth
stage when interpreting results.
IP 3.02.04 - Test Manure or Other Waste Materials for Nutrient Content
Objective
Account for available fertilizer in manure or sludge applications when planning
fertilizer applications.
Description
Manuring, or other waste disposal, should be considered a fertilization procedure, not just
a disposal procedure. Manure and other wastes can contain varying amounts of nutrients.
For accurate management and control of the fertilizer program, all materials to be applied
should be tested for actual nutrient content so that additional applications of commercial
fertilizer are appropriate.
Other concerns when using manure or other wastes on a regular basis include:
1. The rate of mineralization of the waste. That is, how fast the organic nitrogen is
converted to the ammonium (NH 4 ) form, which is available to the plant.
2. The salt content. Dairy and feedlot manures can contain salt concentrations of
50,000 to 100,000 ppm. Large, regular applications to the same field could cause
salt injury or excessive leaching of salts to ground water. It may be beneficial not
to apply manure too close to planting as crops are most susceptible to salt injury
during germination and early seedling stages.
3. Weed seeds. It is often recommended that only well-aged manures be used.
This is because the heat generated in manure stockpiles can reduce the viability
of weed seeds.