Getting Silage Right in a Difficult Spring

Why It Matters

Optimising silage fertilizer use this spring helps Irish beef farms cut costs, increase yields, and meet sustainability targets amid soaring input prices.

Key Takeaways

• Close first‑cut silage paddocks now for optimal yield
• Target 80‑100 N, 16 P, 100 K, 15 S per hectare of silage
• Use slurry (2.5‑3 k gal/acre) for one‑third nitrogen
• Apply compound fertilizer where slurry application is limited
• Aim for soil index three to balance nutrients and productivity

Summary

The Beef Edge podcast episode tackles fertilizer planning for first‑cut silage as Ireland heads into the most productive April‑May window. Host Katherine Egan and Chagas specialist Mark Plunkett discuss how to maximise yield while navigating a difficult spring with limited grazing.

Key recommendations include closing silage paddocks within the next week to allow a 7‑8 day growth window, targeting a dry‑matter digestibility (DMD) of 75 %+ and a harvest around 20 May. Nutrient budgets are set at 80‑100 kg N, 16 kg P, 100 kg K and 15 kg S per hectare, with slurry supplying roughly a third of the nitrogen requirement.

Mark advises applying 2,500‑3,000 gal acre⁻¹ of high‑quality cattle slurry, which delivers 27‑30 kg N and most of the P and K needed. Where slurry cannot be spread due to high cover, he recommends compound fertilizers such as 13‑6‑20 or 12‑8‑20, supplemented with protected urea‑sulphur blends (38‑7 or 40‑7). He also notes that pig slurry can replace a 19‑7‑20 bag, offering a balanced alternative.

Implementing these tactics can boost silage tonnage and quality, offset rising fertilizer prices, and meet environmental standards by improving nitrogen use efficiency to 85‑90 % in the critical spring period. Farmers who align fertilizer applications with soil index targets—ideally index three—stand to improve profitability and sustainability.

Original Description

Teagasc Specialist Mark Plunkett, from the Signpost Programme, is on this week’s Beef Edge podcast to discuss fertiliser application for silage this year.  

As we move through a challenging spring, many farmers are reassessing their silage strategy. Weather disruption, fertiliser costs, and environmental pressures all mean that getting the basics right has never been more important. Mark outlines the importance of achieving high-quality silage while maintaining yields and controlling input costs.

Closing date is one of the most important drivers of silage quality. Earlier closing (late March to early April) results in higher digestibility and better feed quality, but typically lower yields. Delayed closing increases bulk but reduces DMD (dry matter digestibility), impacting animal performance.

Mark highlights how this spring, some ground may not be grazed before closing due to poor conditions. In these cases:

· Remove heavy covers early if possible through light grazing

· If not feasible, close, fertilise and harvest early May

· Avoid applying slurry on very heavy covers—this can lead to contamination

Mark explains that a typical fertiliser programme should aim to supply:

· Nitrogen (N): 80–100 units/acre (100–125 kg/ha)

· Phosphorus (P): 16 units/acre (20 kg/ha) where required

· Potassium (K): 80 units/acre (100 kg/ha), especially where silage is removed annually

Sulphur is often overlooked but is essential for nitrogen utilisation and good grass growth. Deficiency can limit yield even where nitrogen is applied. Including sulphur (10–15 units/acre) improves overall response.

Finally Mark highlights:

· Close remaining silage ground as soon as conditions allow

· Apply fertiliser promptly after closing

· Use slurry where conditions are suitable

· Monitor covers and plan cutting dates early

Timeliness is critical - delays now reduce both yield and quality.

For more episodes from the Beef Edge podcast, visit the show page at:

https://www.teagasc.ie/thebeefedge

Produced on behalf of Teagasc by LastCastMedia.com (https://www.lastcastmedia.com/)