Second grazing – when to start and how much fertiliser to apply

DAIRY: If you’re behind, use the grass on the first grazed paddocks to decide when to start the second round. On most farms, now is an ideal time to apply fertiliser to boost grass growth. Now is a great time to spread slurry, where possible, using the low emission slurry spreading equipment.

In this first clip, George Ramsbottom, Teagasc Dairy Specialist provides us with a summary of the grassland management tasks for March 2020.

When to start the second round?

With grass growth starting to take off and grazing conditions improving, now is a good time to look again at your spring rotation and decide on how you are going to start the second rotation. There are three different situations on farm at the moment:

1. Farmers who are on target to finish the first round by early April. These have 2/3 or slightly more of the farm grazed at this stage. Recovery of the first grazed paddocks is good with covers on them now of around 600 - 700 kg DM/ha.
2. The second group of farmers is those who had difficulty getting house out in February and only have around one third of the farm grazed at this stage. What will determine when the first rotation will end is the recovery of the first grazed paddocks. When three or four of them have a cover of around 1,000 kg DM/ha, it will be time to start the second rotation. If the last of the first rotation has not been grazed at that stage, they should consider closing up 10 to 20% of the grazing area for an early-May cut of silage. This will be high-quality baled silage. This grass will be an excellent supplement for milking cows later on in the grazing season.
3. The third category of farmers is typically those on heavier soils who were badly affected by the wet February and early March. They have only 10 to 20% of the grazing area grazed by now (March 23^rd). Again recovery of the first paddocks grazed will determine when the second rotation should start. Typically I’d expect that this will occur around April 20^th and they should consider making some high-quality bales from the ungrazed paddocks between early- and mid-May.

When to start second rotation? George gives advice here.

March fertiliser and slurry recommendations

From a nitrogen fertiliser perspective, in most situations, now is an ideal time to apply some irrespective of whether nitrogen or slurry was applied last month. At most stocking rates we are recommending a bag of protected urea per acre should be applied. In situations where phosphorus and potassium is low, subject to nutrient management advice, up to 2 1/2 bags of 18:6:12 per acre will give an excellent boost to grass growth. Particularly on silage fields or paddocks where round bales have or will be taken; an application of approximately 2-3000 gallons per acre of cattle slurry is an ideal manure to replace lost phosphorus and potassium. This should be applied using one of the low emission slurry spreading methods to maximise uptake of not just the phosphorus and potash, but also the nitrogen it contains. Using the low emission slurry spreading equipment will also allow you to regraze pasture without rejection or grass contamination if making silage from it.

In this clip, George Ramsbottom talks about spreading the correct quantities of fertiliser, what fertilisers to spread and where to spread slurry. Watch here