Getting Started

The goal of a nutrient management plan is threefold:

• Utilize plant nutrients for crops
  • At the proper rate
  • Include all nutrient inputs
• Distribute manure evenly on the farm
  • Avoid high soil test P areas
• Avoid application where losses occur
  • Steeply sloping ground
• Near surface water
• Shallow or sandy soils

Practically speaking, it is to balance manure disposal with nutrient utilization and environmental concerns. Manure is a valuable resource even with the uncertainties associated with its use, such as application rate, uniformity of application, nutrient content, residual availability, and weather effects. There are, however, standard "book" estimates as published by the University of Wisconsin that we can use when calculating nutrient availability:

How manure is handled can also affect its nutrient availability. Stacking or composting reduces the nutrient content and the nutrient availability. On the other hand, incorporating immediately reduces the N volatilization and reduces runoff. Other factors that need to be considered before putting together a plan are environmental rules:

• Proximity to water (surface application)
  • 200’ from streams, lakes
  • 200’ from wells, sinkholes, gravel pits, etc.
  • No spreading in waterways, wetlands, terraces, etc.
• If surface applied, limited to a maximum rate of 75 lb/a of P₂O₅

And finally, you need to decide whether to use an N-based strategy or a P-based strategy. (Many cost-sharing and watershed programs have specific requirements.)

The following is a simple system to help farmers make smart decisions about manure application: