The Fertilizer Association of Ireland
Advice to help alleviate the current fodder crisis of spring 2018
With air and soil temperatures recovering and soils beginning to dry out it is time to focus on
fertiliser to maximise grass growth and reduce the burden on purchased fodder and concentrates.
Growth rates have been very poor over the past weeks and we can expect some compensatory
growth to occur as conditions improve. Planning your fertiliser programme is essential to maximise
this growth. Fertiliser provides an excellent return on investment.
All advice below is subject to Soil test results, Nutrient Management Plan & Crop Offtake.
1. Do I need to use an NPK compound or straight N?
Best practice is to use a NPK/High N compounds early in the grazing season especially where
no slurry was applied.
2. What level of Nitrogen do I need to apply this month?
3. Should I be using CAN or Urea?
Both are equally effective as an N source. Urea will work well in current damp conditions.
However as soils dry out urea can be exposed to volatilisation. Use CAN or protected Urea as
the N source in these conditions.
4. When are soil conditions suitable for fertiliser application?
If machinery is marking/tracking ground then soil conditions are not suitable. Select dry
fields to apply fertiliser. Avoid application if heavy rainfall is forecast in the next 24-48 hours.
5. I did not get slurry out this spring, is it now too late?
Where grass has not been grazed slurry will cause contamination to the sward. Graze these
swards and then apply a light coat of slurry. Slurry is best retained for silage ground.
6. I have fertiliser out but have had heavy rain in the last 2 weeks, do I need to re-apply?
Monitor these swards over the next week as growth picks up. If they seem lacking in
nutrition an additional application may be required.
7. I have poached paddocks, how will I get them to recover quickly?
At soil index 1 and 2 (where permitted under nitrates) spread up to 5 units of P/acre to
promote root development and tiller sward. If cases of severe poaching consider over
8. Spring application of potash?
High applications of Potash K under current conditions should be avoided due to the risk of
grass tetany. More K can be applied later in the season as the weather warms up and the
risk will be reduced.
9. Is sulphur of any benefit to me this early in the season?
Yes Sulphur will increase N efficiency, boost yields and increase grass proteins. Aim for a
little and often approach for sulphur. 16 Units/acre over the grazing season.
It is imperative that actions are taken not to compromise quality and quantity
of next winter’s winter fodder.
• Silage ground needs to be closed by the middle of April and cut by the end of May to
• Each week late in cutting silage after heading out date will decrease DMD by 7 units
and delay second cut by 2 weeks.
1. What level of Nitrogen do I need for 1st cut silage?
Advice is to use 80 units for permanent pasture and 90 Units for reseeds
Generally allow 2 units/day from application date to cutting date.
2. Should I delay cutting to increase volume?
For quality silage harvest crop in late May. Grass will seed/shoot-out between 20th and 25th
3. How will I increase silage made this summer to replenish my reserves?
Aim to increase volume in second and subsequent cuts. Also maximise bales taken from
paddocks during the grazing season.
4. Is it too late for slurry on silage ground?
If there is a cover of grass then slurry application will contaminate the grass unless spread
with a trailing shoe/injected.
5. What level of P and K do I need for 1st cut?
P requirement is 16 units/acre. K requirement is 100 units/acre. Reduce accordingly for
earlier applications of slurry and/or chemical P K applications. If no chemical K or slurry has
been applied reduce K to 60/70 units to avoid luxury uptake of Potash.
6. Silage ground has not been grazed, what should I do?
Leave it closed up and fertilise as soon as possible and go for an early harvest date.
7. Do I need sulphur?
Yes Sulphur should be applied up to 20 units/acre/for each cut. It will increase grass protein
and increase nitrogen efficiency.
1. When is the best time to apply lime?
Lime can be spread at any time once ground conditions allow, however care must be taken
to avoid contamination of grass. Where the risk of contamination to grass occurs use
Granulated Lime as a short term solution as soon as possible and plan a bulk ground
limestone programme later in the season.
Lime is essential to maximise the returns from fertiliser as shown in the graph below.
Raising soil pH from 5.5 to 6.5 will increase the efficiency of fertiliser by >25%.
Lime will deliver a return on investment of 7:1
2. Can I spread urea after bulk lime application?
Do not apply Urea within 3-6 months of bulk lime application.
3. Can I spread fertiliser after slurry application?
Maintain a 1 week interval between slurry and fertiliser application.