DO IT NOW: Soil test and plan next year’s nutrient requirements

Like animals, plants need nutrients to grow. Good nutrient management is one of the keys to farm profitability. If essential nutrients are in short supply, plant health and yield will be affected.

A soil test is essential to help identify nutrient availability. The results should be used to produce a nutrient management plan to match nutrient inputs (fertilisers and organic manures) to crop demand. This means that nutrient use is tailored for optimum uptake and yield, minimising nutrient losses to the environment. Nutrient planning should be provided by a FACTS nutrient management planning accredited adviser.

It is a good time to collect a representative soil sample from the field. Poor sampling can lead to inaccurate results, which can increase costs through unnecessary applications or reduced yields.

How to test
  • Twist a gouge or pot corer down to 7.5cm
  • Walk the field in a ‘W’. Avoid gateways, feeding areas or former muck-heap sites
  • Collect 25 plugs of soil in a clean bucket
  • Seal a well-mixed sub sample in a plastic bag or box and label
  • Send to an accredited soil testing laboratory (either direct to the laboratory or via a local co-operative, fertiliser merchant or independent company)

For fields that are being regularly cut for hay and silage, soil samples should be taken every three years as significant levels of nutrients are being removed.

For fields that are grazed and have historically had optimum fertility levels, soil sampling every five to eight years should be sufficient.

Ideally, samples should be taken in the same season and at least two months after the last application of manure, fertiliser or lime. Prioritise fields that underperform, are going to be reseeded, that have received a lot of organic manures, such as muck, slurry or digestate, or where perennial ryegrass content is noticeably declining.

Sample areas of the field known to differ separately, eg soil type, previous cropping and nutrient applications. Small areas which vary from the majority of a field should be excluded from the sample.

For more information, see the BRP manuals Managing Nutrients for Better Returns and Improving Soils for Better Returns.

A list of soil sampling companies can be found and