Soil Nutrient Management Planning – A cost or an investment?

By Luke Clogher, Teagasc Walsh Fellowship Masters Student, Teagasc Castlerea.

Soil is the most important asset on any farm, as all outputs are derived from it. Therefore, it’s essential that it’s looked after using best practice along with good nutrient management. A Nutrient Management Plan (NMP) is what’s needed to ensure fields get the correct nutrients to make sure soil fertility is sufficient to carry the farm’s stocking rate or support a profitable crop yield. Firstly, soil samples must be taken to establish current soil fertility. Don’t sample a field until 3 to 6 months after the last application of P or K fertiliser or slurry i.e. NOW is a good time to sample! Although the maximum area 1 sample can cover is 5 hectares, samples should be taken strategically to cover different soil types, cropping histories (grazing or silage) and field divisions. Consider a 60 acre (24 hectare) farm. Taking 7 soil samples will cost €175 or €44/year for 4 years. This is just a 73c/acre/year investment to determine the farm’s soil fertility status and remove the guess work regarding soil nutrient requirements. A NMP based on soil sample results will tailor recommendations for your farm. Each field’s N, P and K requirements will be determined by your soil indexes, stocking rate and slurry available. For example, low P and K index fields will be identified and targeted for slurry application allowing the balance to be made up with purchased fertiliser. Similarly, lime requirement recommendations based on your field’s pH, will increase the nutrient availability (N, P & K) within those soils. This is why lime is regarded as ‘the forgotten fertiliser’. A NMP will give you the confidence that you’re only applying the nutrients you need and only where they are needed. With the combined trend of increasing fertiliser prices and tighter profit margins, it’s essential that fertiliser, slurry and lime are used efficiently for maximum return. Some farmers believe that cutting back on fertiliser and lime may help the bottom line, but in reality, if soil nutrients are not replenished after a grazing or harvest, soil fertility and production will decrease quickly. This will inevitably result in increased purchases of alternative feeds to grazed grass and silage, which can be up to 10 times more expensive per unit of dry matter.

As the saying goes, “look after your soil and it will look after you”. Contact your local Teagasc office for more information.

Teagasc provides a Local Advisory and Education service to farmers. They have offices based in Longford Town (Tel: 043 3341021), Roscommon Town  (Tel: 090 6626166) and Castlerea (Tel: 094 9620160), You can find us online at on Facebook @Teagascroscommonlongford and twitter @teagascRNLD