By Martina Harrington, Teagasc drystock specialist
The wet weather of early spring 2020 has disrupted the spring rotation planner and that now needs to be adjusted to reflect the circumstances.
But, saying that, things are finally looking up in the east with cattle beginning to appear out on the driest of paddocks.
The wet weather has really messed up the spring rotation planner and it now needs to be updated. If left as is – with the end of our first rotation on April 10 or ‘Magic Day’ – it is leaving the first rotation very short.
That means if a paddock is grazed today and you want to go back and graze it at 1,250kg of dry matter (DM) in 23 days, growth rates would have to be on average 54kg DM/day – this is unachievable.
However, if the start of the second rotation is pushed out by 10 days, the average growth rate needed will be reduced.
The spring rotation planner needs to be adjusted to reflect this. There will need to be a balance between getting paddocks grazed off to have grass there for the second rotation and getting silage ground grazed and closed up.
You may need to leave some silage ground un-grazed and cut early to end the first rotation on time. This plan may need updating as you go along.
Fertiliser
The application of fertiliser will be critical. There are several different scenarios out there, but what should you do now?
1) No fertiliser applied at all
Apply 1.5 bags of 18-6-12 to the whole farm as soon as ground is travelable. Check your nutrient management plan to ensure you stay within the limits; if 18-6-12 is not allowed use protected urea.
Apply on the driest paddocks first and follow up with the wetter ones as they dry. The target is 27 units of nitrogen (N) and phosphorus (P) and potassium (K) will help give you an extra jump in growth.
On heavily stocked farms, follow up with 23-30 units of urea or protected urea in the following three-to-four weeks. Keep your slurry and apply to the silage ground after it is grazed.
2) Slurry applied on some ground; no fertiliser applied
Do the same as above. However, if possible use the fields you applied slurry to as silage ground, so as not to waste the K. With a very short rotation, we need all the push we can get.
If you have high-P soils, you could apply 30 units of straight N to the fields that got slurry.
3) Half a bag of urea applied to 50% of the farm in January
Apply 1.5 bags of 18-6-12 to all fields as they become travelable, as long as your nutrient management planner allows – always watch your nitrates limits, if not use protected urea.
The urea will have grown the grass that is there now, but the 18-6-12 will grow the grass you will need in three weeks’ time.
The aim is to have between 50 and 70 units of N applied by the middle of April.
Heavy ground
While cattle are starting to head out in the east, the west is 7-10 days behind; this will push out the turnout date.
Most paddocks have good covers due to early housing, so the reality is that most of the silage ground will not be grazed this year and should be closed, fertilised and cut mid-May.
Turned out stock should graze 20-30% of the lighter covers (800-1,000kg DM/ha) first and get through this fast and get it growing.
This will also provide an area for slurry to be applied and then head into the heavier covers. The problem here will be that the rotation will be short, but soil temperatures should be up and grass growth rates will be on the rise and very close to demand.
Fertiliser will be key, apply 1.5 bags of 18-6-12 to all paddocks, including those with heavier covers. This will grow the grass you need in three weeks’ time, as long as your nutrient management planner allows. Again, watch your nitrates limits, if not use protected urea.
As tanks are nearly full, spreading slurry with a dribble bar or trailing shoe may be the best option. Apply a further 23 units of N in the form of urea or protected urea on top of the slurry.