Soil Testing and Correcting pH

Soil fertility is critical to allow you to grow more grass on your farm.  Teagasc have compiled 5 key steps to achieving good soil fertility on your farm, see http://www.agritrading.ie/Soil-Fertility-Management for details.

Now is the ideal time (November to January) to address the first two steps, soil testing and correcting soil pH.

Soil testing
Why?
Only 11% of Munster dairy grassland is sufficient in pH, Phosphorus (P) and Potassium (K) to maximise grass growth i.e. pH>6.2, Index 3 or 4 for P + K. 
  

If you have no soil test you are working in the dark and based on the above you will be wrong 89% of the time! 
 
Working with a soil test

 
Working without a soil test!

Unsure how to soil test?  See best practise soil sampling procedure at http://www.agritrading.ie/Soil-Sampling-Procedure

How often should I soil test?
Farmers with a nitrates derogation are obliged to soil test their farms every four years.  However, intensive dairying removes significant quantities of nutrients (particularly P) and your soils’ fertility status can change very quickly.  For this reason, we recommend intensive and significantly expanding dairy farmers soil test their whole farm every two years. Dairy farmers not in this category should still soil test their whole farm every four years.

Action
Don’t let soil testing become a tick box exercise for your derogation plan. Soil testing is an extremely valuable tool if you act on the results.  If you need help in interpreting your soil sample analysis and planning actions based on results, contact your local Dairygold or Teagasc advisor.

Key points
• 89% of Munster dairy grassland requires more lime, P or K to maximise grass growth
• Intensive and significantly expanding dairy farmers should soil test their whole farm every two years
• Ensure you act on the results of your soil tests

Soil pH
Having your soil at low pH means lower grass growth and reduced efficiency of the fertiliser nutrients applied.  The efficiency of Phosphorus (P) is particularly sensitive to pH. If your soil is below a pH of 6 (60% of grassland soils are), it is costing you money as P applied as fertiliser is used less efficiently as shown in the graphic below.  Now is an ideal time to spread lime to correct low pH fields as indicated by your soil tests.

 

For more on how pH influences fertiliser efficiency, see http://www.agritrading.ie/Fertiliser-Efficiency-Ratings

Key point: There is no closed period for lime or K applications.  Spread as required for your farm.

Potash
Since the introduction of the nitrates directive, applications of P have reduced.  Despite, no limits on K applications, applications of K have also reduced because P & K fertilisers are traditionally applied together.  We are now in the middle of the closed period for spreading artificial N and P.  Remember, this is not the case for K.  Now is a good time, provided you can travel ground without damaging it, to spread straight K products e.g. Muriate of Potash (0-0-50) if required.

Get in touch 

For further help and advice contact your local Agri representative

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