The wet spring has prevented many farmers from spreading fertiliser and closing up fields for first-cut silage in early April.

As such, farmers will have to rethink their approach to silage and fertiliser applications.

Outlined are five tips to closing off silage ground this spring.

1. How much fertiliser to apply?

Using the rule of thumb of grass utilising two units/day of nitrogen fertiliser, applying the standard 100 units/acre on 10 April would mean silage is safe to harvest around 1 June.

Obviously, at the outlined fertiliser rate, closing off fields beyond 10 April pushes cutting date further into June. That is less of an issue if the aim is to maximise silage yields.

But if your plan is to harvest grass before it heads out, improving the feed value of silage, then go with a lower fertiliser rate of 70 to 80 units/acre of nitrogen if closing fields before 15 April.

That should allow harvesting silage around the final week of May, provided weather is on your side.

2. Hold off on slurry applications

Most farms are carrying reasonable covers of grass at present, therefore avoid slurry when closing up silage fields.

Harvesting dates are not that far away. Slurry applied to fields with any kind of grass cover has potential to contaminate swards and be carried back into the clamp.

Although slurry applied by a trailing shoe is placed directly on the soil, if not properly diluted, it is left in prominent lines, increasing the risk of contaminating silage.

Therefore, at this stage of the year, going with 100% chemical fertiliser may be the best option for first-cut silage. Slurry can be applied to aftermath after harvest.

3. Lime

If there were plans to lime fields earlier this spring, but wet weather prevented this task, do not lime fields earmarked for silage.

Lime can be brought back into the clamp, inhibiting silage fermentation, as it neutralises pH. If silage fields need lime, hold off until after the final cut is harvested for the season.

4. Splitting the fertiliser allocation

If ground is able to carry machinery, go ahead and close up silage fields. However, with frequent showers in the forecast, consider splitting fertiliser applications to prevent nutrient loss.

Aim for a half rate of fertiliser when closing off fields, then top up before the end of April. It is double the work, but may be cost effective in terms of yield.

5. Weeds and rolling

As soon as ground conditions allow, target weeds such as docks or thistles before grass covers get too strong. Weeds are best sprayed before they mature and produce seeds.

If fields were poached or damaged from silage harvesting in wet conditions last year, hold off on rolling until conditions are right.

Rolling when fields are too soft will create compaction and reduce natural drainage.

Mark damaged areas that can’t be rolled with plastic fencing posts and mow around these areas. Once first cut is lifted, aim to rectify any surface damage then.

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