Soil samples will deliver a cost-saving fertiliser plan

By Joe Curtin, Teagasc Drystock Adviser, Roscommon.

The closed period for slurry and fertiliser is passed and it’s now time to start thinking of fertiliser planning on grassland farms. A fully integrated nutrient plan is what’s needed, based on soil samples that represent your grazing and silage areas. The starting point is to take soil samples, usually taken at a rate of one every five hectares.  Consider your average 70ac (28ha) in this region, taking 8 soil samples to cover different soil types, cropping histories and fragmentation. These samples will cost €200 or €40/year for a 5 year period. For this investment of just 57c/acre for the 5 years, you will get full farm information on where you stand with regard to lime, P and K requirements.

What are the benefits of this approach for your farm?

• A Nutrient Management Plan (NMP) based on soil sample results will be fully compliant with Nitrates Regulations. Your recommended N, P and K fertiliser will be determined by  your soil indexes, your stocking rate and slurry volumes for recycling back on grassland.
• Lime requirement of soils with pH<6 are identified. Following lime application there is a subsequent release of soil N and improved efficiency of fertiliser P.
• Index 3 (medium) is the target for P & K and combined with corrected pH’s of >6, grassland can achieve its full potential throughout the growing season. Well managed grasslands with these levels of fertility are growing 12t DM/ha/yr.
• At today’s prices it’s vital that fertiliser is properly targeted to where it’s needed to give best returns. You can have confidence that your NMP will do this and deliver top yields of grazed grass and silage.
• With tight profit margins across drystock systems, it is vital you should be targeting a long grazing seasons and high intakes of top quality grass. A driving force /starting point for these farmers to remain viable is a proper nutrient plan.

Recycling organic manure/slurry back on grassland can effectively replace artificial fertilisers. To maximise the nutrients in slurry, 6N-5P-38K /1,000gallons, it is essential that they are applied at the correct time of year. Land-spread from late Jan to April will get excellent results once ground conditions prove suitable. 1-2000 gals of cattle slurry/acre will kick-start growth at minimum cost. Slurry should be targeted at the lower index lands as per your soil results and any shortfalls made up with purchased fertiliser. There may be a view among farmers that fertilisers are too expensive and that cutting back may be good for the bottom line!!! Looking at the soil sample results countrywide over the last 5 years there is no evidence to support cutting back on the basis of P and K. It is surprising that only 10% of all soils analysed were in the optimum balance for the major soil nutrients to maximise grass production. The alternative feeds to grazed grass and silage will cost up to 10 times more per unit of DM. Soil testing is the first step in fertiliser planning. NOW, is the time frame before any slurry, FYM or chemical fertiliser is spread, to take soil samples.

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