It says how much grass you need to grow to extend the rotation length will depend on your farms stocking rate. Farms with a low stocking rate may need to spread very little nitrogen at this time of the year. From late August soils naturally release their own organic nitrogen and this may be enough.
Teagasc advises that on heavier stocked farms consider applying a blanket application of nitrogen. The amount to apply will depend how much of your full years allowance you have left and the overall grass supply on the farm. Swards with more perennial ryegrass will respond better to nitrogen and these should be targeted for building autumn grass.
In terms of slurry spread in the autumn, in warmer and drier weather can deliver very little nitrogen that the sward will use but it is still very valuable when it comes to its phosphorus (P) and potassium (K) content (about five units of P and 38 units of K per 1,000 gallons cattle slurry). Teagasc highlights that the key issue with slurry at any time of the year is to spread it on fields that need P and K.
It says ask yourself: “If I were not in the field today spreading slurry, would I have been here with a compound fertiliser?” If the answer is no, should you not be spreading that slurry somewhere else?