Manure application to forage crops can provide both a yield and quality benefit compared to commercial potassium (K) or no application, according to an Oxford Soil and Crop Improvement Association trial.

During the summer of 2006, manure was applied after second or third cut (at rates between 2,000 and 4,500 gallons per acre) after hay or haylage harvest on eight replicated sites. Manure applied to alfalfa-grass crops showed a 12 percent yield increase and a slight quality benefit.

When the quality parameters were compared in a spreadsheet that calculates “milk per ton” of forage, manure applied to forages gave an average 88 pounds more milk per ton (quality improvement) and 229 pounds more milk per acre per cut (yield plus quality).

Advantages of applying manure to forage
The best option is still to spring-apply manure to corn crops, because this option gives the highest economic return from the nitrogen. However, there could be several reasons a livestock producer may choose to apply manure to forage crops. Some of these reasons include:

•spread out workload to less busy times of the year
•reduce manure storage requirements
•prevent compaction damage to soils
•more opportunities and alternative crops to which to apply manure
•lower application rates and lower environmental risk

Manure applied to forage can meet these objectives while providing nitrogen, phosphorus and potassium (N, P and K) that will save commercial fertilizer inputs.

Timely application is important
The greatest challenge in applying manure to forage fields is timely application to prevent “traffic damage.” Haylage fields are ideal since they are harvested more quickly than dry hay crops. It is critical that manure be applied as soon after forage harvest as possible.

When manure is applied to alfalfa regrowth, the plants impacted by wheel tracks must restart growth. This regrowth will be from crown buds, as opposed to a combination of crown buds and apical bud regrowth from stems. Manure applied between 1.5 to 2 weeks after the field was cut risks a yield reduction of up to 50 percent in areas affected by wheel tracks.

Good quality forages are essential to animal nutrition which makes timely harvest for all forage fields a priority to manure application. Therefore, when manure application for forages is considered, adequate labor and equipment are required to be able to combine timely forage harvest with timely manure application. Targeting manure application to last-cut fields or having manure custom-applied are alternative options.  FG

—From OMAFRA Crop Talk, Vol. 7, No. 4

Christine Brown, Nutrient Management Lead, Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)

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