Page 233 - Nutrient Management Planning Guide

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Chapter 6.1

Estimating Additional Land Base Required »

If it has been determined that the existing application area controlled by the operations is insufficient to accommodate annual manure production, the additional area can be estimated:

Additional Area Required = (Annual Manure Production ÷ Calculated Application Rate) - Current Eligible Area

Estimating Additional Land Base Required

The liquid manure source in the previous example had a total volume of 3,200,000 L and the intention is to apply this manure to meet the available P needs, three year application. The calculated application rate for this scenario is 18,181 L/ha, but the operation currently only has access to 130 ha. The additional land base required is: Additional Area Required (ha) = 3,200,000 L/yr ÷ 18,181 L/ha – 130 ha = 176 ha/yr – 130 ha = 46 ha/yr

The two examples above touch on some important calculations that CFO operators should consider. To apply manure at agronomic or sustainable rates many CFO’s may require additional land to accommodate annual manure production. This issue is likely to become of greater concern to producers if legislation is introduced in the future that requires manure application to be based on phosphorus.

Estimating Remaining Fertilizer Requirements

Once manure nutrient application rates have been calculated (or verified after the fact) identify remaining nutrient deficits by subtracting nutrients applied (in manure) from fertility recommendations on the soil report. Fertilizer suppliers can typically develop a fertilizer blend customized to meet specific needs.

tip

Remember to account for nutrients that mineralize from manure with time when calculating fertilizer application rates for subsequent crops.