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Do you know the pH value of your soil?

Tuesday, 22 March 2016

With the introduction of phosphate rights, it’s essential to deal efficiently with the mineral maintenance. A good tool for this is the  cycle indicator. The indicator shows where the strong and weak points are on the farm as far as mineral utilisation is concerned. Higher crop yields can be achieved by dealing with mineral use efficiently, which in turn reduces the loss of minerals. These are important points that you as a farmer can get a better handle on.

But in spite of all the changes, farmers are still not aware enough. The realisation that the soil has to perform optimally has not yet penetrated all the farmers’ operational management. A good example of this is the pH value of the soil. Barenbrug presents hard data on this:

  • 30% of the farmers did not test the pH
  • the pH is too low on 30% of the grassland
  • 50-80% of the corn fields have a pH value of less than 4.8
  • 10% of the corn fields have a value lower than 4.5

These numbers don’t lie; but why is it important to know the pH value of the soil?

A pH that is too low or not optimum has a negative effect on mineral absorption in the soil, so the minerals are flushed out more easily. According to many experts, if the pH is very low (<4.5), fertilising is actually useless. So it is important to know what the pH value of the soil is before you start working it.

We present the pH-KCI target values for sand, reclaimed peatland and peat bog below:

Organic matter content of the soil (%): Target pH
< 5,0 5,3 – 5,7
5,0 – 7,9 5,1 – 5,5
8,0-14,9 5,0 -5,4
> 15,0 4,8 – 5,2

If you want to deal with the mineral management efficiently, you need insight into what goes into the soil besides the soil itself. In other words: what’s in the manure? An increasing number of dairy farmers are getting a manure test done. This is a good development. In practice, we notice that many dairy farmers use average slurry values as the starting point. That, however, is where the problem lies. The reality is that slurry values vary enormously.

Eurofins Agro has the following to say in this regard: ‘Depending, among other things, on the ration and the animal group, the concentrations in slurry vary enormously and from year to year.’

The spread in the slurry values can be seen clearly in the table below. The first column lists the average value. The second column lists the lowest value and the third column the highest value.

  Variation
Average Lowest value Highest value
N 4,0 3,4 4,6
P205 1,6 1,2 2,0
P 0,7 0,5 0,9
K20 5,5 4,0 6,5
K 4,6 3,3 5,4

The table shows how important it is to know what your slurry contains. Therefore we advise: That you have your slurry tested and have the pH value of your soil analysed!

Would you like to know more about fertilising or would you like to make an appointment to draw up a fertilisation plan? If so, please contact Iris Kooijman at +31 (0)592 614 265 or iriskooijman@vibconsulting.nl