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Manure Application Equipment

Manure placement can also be looked at in terms of the uniformity of spread, which will be discussed in more detail in the next chapter. Achieving a uniform distribution of manure will help to ensure that nutrients are applied uniformly to the field. Uniform application will help prevent nutrient deficiencies that may result in uneven crop growth. If operated properly, most application systems, with the exception of liquid tank spreader systems equipped with splash plates, will provide acceptable application uniformity (Table 4.5.2).

Nitrogen Conservation

The predominant form of crop available N in many manures is ammonium (NH

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-N), which is prone to loss through volatilization. The amount of NH

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-N lost is a function of the application and incorporation strategy (both the method and relative timing) and the weather conditions during application (Table 4.5.3).

Application systems that get manure into the soil as soon as possible after application minimize the opportunity for NH

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-N to volatilize. Warm and dry conditions favour greater volatilization compared to wet and cool conditions. Application strategies that help retain NH

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-N will maintain the fertility value of applied manure and therefore, the economic value of the manure.

Potential for Odour Nuisance

Odour is the principle nuisance concern associated with manure application. Generation and emission of odours from manure is a complex process, but in general, application systems that minimize manure contact with air have fewer odour concerns (Table 4.5.2). For example, liquid application systems where manure is deposited directly on or into the ground (i.e., drop tubes and injection) will produce less odour compared to liquid application systems with splash plates. To minimize odour problems, incorporate manure either during or as soon after application as possible.

Soil Compaction

Field equipment weighed down by large volumes of manure may increase the risk soil compaction (Table 4.5.2). The risk is further aggravated if manure is applied in late fall or early spring when soils have higher soil moisture and are more vulnerable to compaction. Where possible, avoid applying manure at times when fields are most vulnerable to compaction. Alternatively consider using systems with a lower risk of compaction, such as drag-hose systems for liquid manure. Refer to Chapter 8.2 for additional ways that soil compaction can be minimized.

Timeliness of Manure Application

CFOs produce large volumes of manure that is typically applied only once or twice per year. Depending on the capacity of equipment, the application rate and the distance of the application area from the storage facility, manure application can take days or even weeks.

Any system that must return to the storage facility to be refilled will take the longest to apply stored manure (Table 4.5.2). Systems that use an intermediary, such as a nurse tank that transports manure from the storage facility to the application field and allows the applicator to stay in the field, will require less time. Liquid drag-hoses are the most time efficient application system because manure is continuously pumped from the storage to the applicator in the field.

A system’s ability to get manure out into the field in a timely manner will save the operation money in labour and equipment costs. There is also the opportunity to minimize nutrient losses and nuisance (odour and transportation).