Soil Fertility Management

Fertiliser use and soil fertility headlines
• 55% of soils tested in Ireland in 2013 were low (index 1 or 2) in Phosphorus (P)
• 52% of soils tested in Ireland in 2013 were low (index 1 or 2) in Potassium (K)
• 80% of soils tested in Ireland in 2013 were short in lime for optimum crop growth (below pH 6.5)


The Teagasc 5 Steps to Soil Fertility Management
1 Soil Testing
Only 13% of tillage soils are optimum for crop growth (pH>6.5, Index 3 or 4 for P + K).  If you have no soil test you are working in the dark and will be wrong 87% of the time! Soil testing is a relatively small cost versus the cost of fertiliser.

In the autumn from stubble ground after harvesting or early spring before you spread lime/organic manures/P&K fertilisers (which can interfere with results).
See best practise soil sampling procedure under ProductsServices

2 Soil pH
Having your soil at low pH means reduced efficiency of the fertiliser nutrients applied.  The efficiency of Phosphorus (P) is particularly sensitive. If your soil is below a pH of 6 it is costing you money as P applied as fertiliser is used less efficiently. 

3 Target Index 3 for P & K
What do the soil indexes mean?

4 Make the best use of Organic Manures
Organic manures from your own or neighbouring livestock farms are valuable fertilisers and can offer significant cost savings e.g. below are some typical values of organic manures
• 4,500L (1,000 gallons) of cattle slurry equivalent to 50Kg (cwt) bag of 6-5-38

• 4,500L (1,000 gallons) of pig slurry equivalent to 50Kg (cwt) bag of 19-7-20

• 1 tonne of farmyard manure equivalent to 50Kg (cwt) bag of 3-2.5-12

The majority of value of slurry is in P and K.

Where should I spread slurry?
Slurry should be targeted and fields low in P and K (index 1 and 2).

5 Use artificial fertilisers to balance nutrient requirements
The nutrient in shortest supply in your fields limits crop growth.  This is especially true for P and K. Make sure you are applying the right fertiliser compounds in the right fields on your farm.

Key points:
1. Soil test: 87% of tillage soils are low in lime, P or K
2. Apply lime as required-The effectiveness of the fertiliser you spread is directly related to soil pH
3. Target index 3 for P and K.
4. Apply slurry where P and K are required
5. Choose the right compound to balance your requirements

Get in touch 

For further help and advice contact your local Agri representative

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