We are at challenge nine of our 10 BETTER Farm Beef Programme challenges and the soil health challenge is up for review.

This wasn’t a mandatory challenge, but 21 out of the 23 programme farmers signed up to the task.

Their objective was to improve soil fertility on their farms through frequent soil sampling and targeted applications of lime and organic and chemical fertilisers based on nutrient plans.

Targets

When we talk about growing more grass, the first thing that comes into most people’s minds is either infrastructure – like putting up paddocks, roadways and/or water troughs – or reseeding. And while there is no doubt that these factors can lead to improved grass production, the factor underpinning this is soil fertility.

Trying to grow more grass on land with poor soil fertility is like trying to drive a car with the handbrake on – a futile exercise.

The three key ingredients of soil fertility are pH (lime), phosphorous (P) and potassium (K).

When looking at the targets and ultimately correcting soil fertility, lime is the first port of call

What about nitrogen (N)? Well let’s use another mechanical metaphor – N is the fuel that powers grass growth during the growing season, but P, K and lime are the engine that drives the growth. No matter how much fuel you use, it won’t work without an engine.

When looking at the targets and ultimately correcting soil fertility, lime is the first port of call. On normal mineral soils, we target a minimum pH of 6.3 – below this, the soil will be more acidic. On peat-type soils, the target is for a minimum of 5.5

P and K are measured in mg/litre and graded on a one-to-four index scale based on the probability of a response to fertiliser application. Index one means a definite response and index four means no response. Needless to say, the target is for our fields to be at index three or four, which corresponds to at least 5.1mg/l of P or 101mg/l of K.

Maintenance

Significantly, once a soil reaches index four, only maintenance spreading is needed in order to account for the off-take via animals or conserved forage. To build up P and K, organic sources (slurries and FYM) and chemical fertilisers (18:6:12, 10:10:20 etc) are the most common options.

While this all sounds relatively straightforward, alarmingly only 10% of soils in Ireland are optimum for all three soil nutrients. The only way for you to know what your soil situation is, is to soil sample. Pending those results, a nutrient plan can be drawn up for your farm – including lime, fertiliser, slurry and FYM – to correct nutrient any nutrient deficiencies (see top tips for soil sampling) and kick-start your effort to grow more grass this year.

Inside this week's Irish Farmers Journal we look at how the BETTER farmers have changed their soil fertility over the last three years and we also take a look at some top-tips for soil sampling.