Manure, Compost and Fertilizer
All 3 materials provide crops with N, P, and K, so why choose one over the other?
•Differences in nutrient content
•Effects on plant yield, vigor and health
•Effects on soil tilth
•Transportation, application and cost differences
Commercial fertilizers : AA, AN, UAN, UR (Urea) MAP, DAP etc.
• Manure: No explanation needed!!
• Compost: Decomposed/stabilized organic matter.
Compost examples include:
• Food Processing Residuals—compostable material remaining after fruit, vegetables,
grains, nuts, and meat are processed for consumption.
• Manure and Agricultural By-Products—originate at feed lots, on the farm, and in
greenhouses. Large quantities of manures and/or plant residues are generated and can
pose a severe disposal problem.
• Forestry and Forest Product Residuals—includes bark and sawdust, and fiber fines,
residue and biosolids generated by the papermaking process.
• Biosolids, or Sewage Sludge—the solid material generated by the biological treatment
of sewage at a wastewater treatment plant. In addition to being composted, sewage
sludge can be recycled for beneficial use by direct application to land as a fertilizer.
• Leaves, Brush and Yard Trimmings (Yard Waste)—typically consists of leaves,
brush, and grass clippings common to urban areas.
Commercial Fertilizers
Advantages
• Precise amount of N, P, K
• Available in a range of nutrient levels
(especially when blended) to provide the
producer what is needed for the crop
• Uniform material for ease of transport and
application
• Known properties of the material with
predictable effect on crops
• Widely available
Disadvantages
• Costs vary and change during the year, and
are currently at record highs
• Often have higher chance for nutrient runoff
or leaching, because of high solubility.
Manures
Advantages
• Often free (except for transport/application)
• Adds organic matter (OM) to the soil which
improves structure, increases water holding
capacity, increases CEC and reduces erosion
• Provides both available and ‘slow-release’ N,
P, K and micro-nutrients to crops
Disadvantages
• Nutrients can be easily leached through the
soil profile or volatilized if left on the surface
• Nutrient content is highly variable
• May introduce human pathogenic bacteria
such as fecal coliform or E.coli
• May introduce weed seeds
• Weight and bulk of transporting and applying
wet manures to fields.
Compost
Advantages
• Lower water content: greater total concentration of
nutrients than manure on wet basis
• Adds OM that releases nutrients slowly
• High OM content improves soil structure, increases
CEC and water holding capacity
– Greater water holding capacity may decrease
irrigation needs and reduce pumping costs.
Disadvantages
• Making compost involves costly equipment,
planning, monitoring and time to produce
• Nutrient enriched leachate must be controlled
to prevent runoff or ground water
contamination.
Making Compost - https://eagrovision.com/how-to-compost-in-your-garden-2019/
Summary
Decisions on fertilizer vs. manure vs. compost
depend on:
• Having quantities or easy access to those materials.
• Comparing costs of fertilizer vs. manure vs. compost
and their associated application costs.
• Providing the right amount of N, P, and K for your
crop.
• Your choice on whether you want to build soil O.M. or
not.