Several myths about the waste from intensive livestock operations have developed, which confuse the debate about their contribution to the agricultural sector.
MYTH #1
All manure lagoons stink.
Odor is one of the most contentious issues of public concern with the expanding livestock industry because offensive odor is difficult to measure. A general rule for the amount of odor production in a typical hog operation is: 25 percent from the barn; 25 percent from the manure storage facility; 50 percent from the field application of manure.
Odors can be best managed and kept at minimal, tolerable levels by:
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- Keeping the barn well ventilated and at appropriate temperature and humidity.
- Keeping manure lagoons covered, such as with straw, and surrounded by trees.
- Injecting liquid manure into the soil or incorporating solid manure immediately after application.
MYTH #2
The nutrient content of manure is too variable to use as a fertilizer.
Nutrient content of manure can vary dramatically from one operation to another or from the start of a pumping-out operation to the end, if not thoroughly agitated.
This can be overcome by conducting an annual laboratory manure analysis once the stored manure has been thoroughly agitated. Field test kits are available to measure nitrogen and phosphorus to determine nutrient levels and adjust application rates.
These should be verified with a laboratory analysis. Do not use your neighbor’s manure analysis. You are better off using an old manure analysis from your own farm, provided you have not changed your feed ration or manure handling practices from past years.
MYTH #3
Manure should not be applied to sandy soils.
Although the risk of nitrate leaching is greater on sandy soils than on heavier textured soils, manure applied at proper rates to meet targeted crop production needs should pose no greater risk of nitrate leaching than does commercial fertilizer.
In fact, the risk could be less than commercial nitrogen fertilizer because a portion of the total nitrogen in manure is in the organic form, which slowly becomes available over time.
The usual recommendation is an application of 60 pounds of nitrogen per acre to sandy soils for annual crop production, but be sure to test soils for a specific recommendation. Check provincial waste regulations. In Manitoba the livestock waste regulation states the amount of nitrate-nitrogen in the top 60 centimetres (two feet) of a sandy soil shall not exceed 90 lb. of N/ac.
MYTH #4
Manure cannot be injected into forage or zero-till fields. It must be broadcast.
Equipment is available for surface banding or low-disturbance injection into forage or zero-till ground.
MYTH #5
Heavy metals build up in the soil from manure applications.
Manure contains small amounts of heavy metals, such copper and zinc. They may not be immediately or completely available to the crop, but even assuming they are completely unavailable to the crop, astronomical application rates over time would be required to exceed Canadian soil quality guidelines. Applying manure to meet either nitrogen or phosphorus targets should prevent heavy metals from building in the soil.
MYTH #6
There is no quick and accurate way to test manure nutrient levels in the field.
Field test kits for both ammonia (plant-available nitrogen) and phosphorus are available to allow for rapid (five-10 minutes) determination of manure nutrient levels.
Last year’s manure analysis data showed that the field test kit for ammonia was accurate to within +/-10 percent of ammonia levels determined in the laboratory. Phosphorus has been shown to be correlated with the dry matter content of manure, so the field test kit developed for phosphorus measures the solids content of manure. Plans are under way to test the phosphorus kit in Manitoba in 1998.
