Manure Application Rate Calculator

Work out manure application rate instantly with clear inputs, formula shown and shareable results.

About Manure Application Rate Calculator

Only part of manure nitrogen mineralises in the year of application — typically 25-35% for farmyard manure, more for poultry litter and slurry. The rate needed is therefore N requirement divided by (manure N content x first-year availability). The remaining nitrogen becomes available in later seasons and should be credited then.

Formula

Manure rate

Rate (kg/ha) = N required / (manure N fraction x first-year availability)

Worked example

With the default values below, Manure Application Rate Calculator returns Manure Application Rate of 66.67. Change any input above and every figure here is recalculated in your browser.

Inputs used

Nitrogen Requiredminimum 0 kg N/ha: 100 kg N/ha
Nitrogen Content Of Manureaccepts 0.01–10 % of fresh weight: 0.5 % of fresh weight
First-Year Nitrogen Availabilityaccepts 1–100 %: 30 %
Areaminimum 0.01 ha: 2 ha

Results

Manure Application Rate: 66.67
Total Manure Required: 133.33
2-Tonne Trolley Loads: 66.67
Total Nitrogen Applied Per Hectare: 333.33

Step by step

1Values used
2Manure rate
3Manure Application Rate= 66.67
4Total Manure Required= 133.33
52-Tonne Trolley Loads= 66.67
6Total Nitrogen Applied Per Hectare= 333.33

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Manure nitrogen and phosphate can pollute groundwater and surface water. Many jurisdictions cap organic nitrogen loading (commonly 170 kg N/ha/year) and restrict spreading dates and distances from watercourses.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Manure nitrogen and phosphate can pollute groundwater and surface water. Many jurisdictions cap organic nitrogen loading (commonly 170 kg N/ha/year) and restrict spreading dates and distances from watercourses.

Frequently Asked Questions

Why is total nitrogen applied so much higher than the requirement?

Most manure nitrogen is in organic form and mineralises slowly. Sizing on the available fraction means a large total N loading, which builds soil organic matter but must be tracked against nutrient limits.

Does manure supply phosphate and potash too?

Yes. Farmyard manure at 20 t/ha typically supplies 40-60 kg P2O5 and 60-100 kg K2O, so deduct that from the mineral fertiliser plan or phosphate will be badly over-applied.