Key facts
- Heavy silage cuts remove 8-16kg P/ha and 50-100kg K/ha.
- 1,000 gallons of cattle slurry (6% DM) contains 6 units N, 5 units P, and 32 units K.
- 1,000 gallons of pig slurry (4% DM) contains 19 units N, 7 units P, and 20 units K.
- Teagasc advises applying 50-100kg N/ha for second-cut silage.
- Slurry should be applied 7-10 days before chemical fertiliser for silage ground.
Farmers are planning for second-cut silage following a delayed spring that impacted first-cut silage operations. Heavy silage yields can deplete soil phosphorus (P) and potassium (K) levels, with a crop removing between 8-16kg P/ha and 50-100kg K/ha depending on yield. Teagasc recommends replacing these nutrients, suggesting that slurry is a cost-effective option given high chemical fertiliser prices. Cattle slurry (6% DM) provides approximately 6 units N, 5 units P, and 32 units K per 1,000 gallons, while pig slurry (4% DM) offers around 19 units N, 7 units P, and 20 units K per 1,000 gallons. These figures are guides, and slurry testing is advised for accurate nutrient content. For second-cut silage, Teagasc advises applying 50-100kg N/ha, achievable through chemical fertiliser, slurry, or a combination. If using both, slurry should be applied first, followed by chemical fertiliser 7-10 days later. Farmers are reminded to be aware of fertiliser allowances and to prioritise safety during this busy period.