By Hannah McNelis,
Sustainable Land Management Branch, CAFRE
SOIL sampling is the place to start when managing nutrients and soil fertility. Soil analysis determines the fertility of your soils, allowing you to plan manure and fertiliser applications to maximise crop yield, minimise wastage and nutrient loss and make full use of your slurry and manure.
Only 18 per cent of soils analysed in Northern Ireland are at optimum fertility for pH, Phosphorus (P) and Potassium (K).
The period from October to February is the optimum time for taking samples as soils should not be tested within three months of the last application of lime, slurry or chemical fertiliser in order to achieve accurate results.
For areas similar in use and soil type, up to 4ha in size, take 20-25 cores across the field. Avoid troughs, gates, headlands, manure patches and where stock shelter.
Mix the cores well in a bucket and place a representative sample of approximately 500g in a bag and label properly with name, farm survey number and field number.
Soil analysis will determine lime requirement (measured by pH), soil phosphorus status and potassium status. These are the main nutrients required for improving nutrient availability, root development, water balance and energy provision of the plant.
P and K status are expressed on the soil report as an index. The optimum index for K is 2-. Whilst in general the optimum index for P is 2, for extensive grazing a P index of 1 is adequate. The optimum pH for grass is 6.0, while for cereal crops it’s 6.3-6.5.
The soil analysis report will specify a recommendation for Phosphorus and Potassium if required. These are maximum amounts and where possible should be supplied from slurry or farmyard manure and only topped up with the right chemical fertiliser at the right rate to make up the balance.
It’s important to remember that under the Nitrates Action Programme 2015-2018 and Phosphorus Regulations you are only allowed to apply Phosphate (P) fertiliser or P rich manures (layer litter, pig manure) if you can demonstrate there is a crop requirement.
Now is the time to get out and take soil samples and make use of your soil analysis report.
Remember this will help you grow productive crops, save money on chemical fertiliser, improve and maintain soil fertility and help improve water quality.
Soil augers and sample bags are available from your local DAERA Direct office along with instructions and guidance in taking your samples.
n Further information on managing nutrients and understanding your soil analysis report is available at: www.daera-ni.gov.uk/5-steps-to-managing-nutrients