Page 174 - Nutrient Management Planning Guide

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Manure Test Interpretation

It may be necessary to convert units •

appearing on the lab report. Use the conversions in Table 4.3.3 to convert between units. Organic N content of manure is estimated •

as the difference between total N and ammonium N content. For fresh manure assume that 25% of the •

organic N will become available in the year of application, 13% the following year and 6% the year after that. For composted manure assume that 12% of the organic N will become available in the year of application, 7% the following year and 4% the year after that. Crop available N in manure is equal to the •

sum of available organic N in the year of application and retained ammonium N content of the manure.

Assume that 70% of total P is available in •

the year of application, 20% the following year and 6% the year after that. Assume that 90% of K is available. Neither EC or pH have clear implications •

for manure application, since the

relationship between manure and soil pH and EC are not well defined. A measure of C:N ratio in manure can •

be useful for identifying potential N availability issues in manure containing substantial amounts of bedding. Nitrate concentration is usually very low in •

raw manure, but can be present at higher concentrations in compost. Any NO

3

-N should be factored into the estimate of crop available N.

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