Arable silage is attracting renewed interest this year and it’s not hard to see why. The late spring has put pressure on feedstocks with silage pits almost empty, so sowing an arable silage crop now could provide a useful source of high protein forage later in the season.
And being compatible with an undersown grass crop, particularly those including red clover, it will also support your spring reseeds.
Protein Aid Scheme and Protein/Cereal Mix Scheme
Arable silage crops eligible for payment in the scheme must be a 50/50 protein cereal mix, with at least 50% of the seeding rate ‘eligible’ protein crop seed – the remainder a cereal seed. The ratio of protein to cereal should be 50% and cannot drop below 40%.
Eligible proteins are beans, peas and lupins. The crop must be grown to a commercial standard with the appropriate seeding rates. For the Protein Aid Scheme, the Protein/Cereal Mix cannot be undersown with grass. More information can be found on gov.ie.
Climate smart forage crop
Arable silage crops comprise a blend of cereals and peas, with oats or barley the most common cereal component. Peas provide a rich source of homegrown protein and, as legumes, can fix nitrogen, reducing the need for applied fertiliser; both clear advantages making environmental and financial sense.
An arable silage crop is harvested at 10 to 12 weeks, at least a month sooner than wholecrop silage, and this is the reason why it makes a valuable nurse crop for grass reseeds.
In the first few weeks after a grass or grass/clover mixture is undersown, the arable silage crop outcompetes weeds, allowing grass to reach its full potential. This is particularly useful for reseeds including red clover where chemical weed control is so limited.
Once well established, when the arable silage is cut, the new grass sward can take advantage of being able to access maximum sunlight. In contrast, because wholecrop silage stays in the ground longer, it restricts light from the new sward for too long, compromising its growth severely.
Under an arable silage crop, the new grass should be ready for grazing four to five weeks after the silage crop is removed. For cutting, it is around seven to eight weeks.
Sowing an arable silage crop with a grass or grass/clover mixture underneath also protects the soil surface by keeping a crop in the ground; another climate smart element of good crop management.
Arable silage crops can be sown from April until June at a rate of 50 kg/acre (125 kg/ha) when undersown with grass. Normal grass seed sowing rates of 14 kg/acre (35 kg/ha) apply, using a perennial ryegrass or grass and clover mixture.
Sow the arable silage crop first, at a depth of 1”, followed by the grass/clover mixture and roll well. Also apply three bags of 10:10:20 at this stage. No further nitrogen needs to be applied as the peas will fix what’s required.
When the silage crop is cut, allow time for a good wilt, ideally up to 48 hours in favourable conditions, aiming for 30% dry matter (DM). An additive is also recommended to encourage its preservation.
Expected performance of arable silage
A crude protein content of 13-16% and DMD of 60-65%, makes arable silage ideal for dry cows or store cattle.
Harvested at 10-12 weeks with a DM of 30%, arable silage is expected to yield 30 tonnes/ha fresh weight or 9 tonnes/ha DM.
And with the silage cut at a time before the grain is developed, the risk of rodent damage is greatly reduced increasing the quality and quantity of feed in the pit.
In a year when rebuilding forage stocks is paramount, sowing an arable silage crop now offers an additional source of silage and another sustainable option for increased resilience across the coming season.
The ability to outcompete weeds and protect a new red clover sward was what first attracted Eugene Kirrane to trying a barley/pea silage crop on his organic farm in County Mayo.
“With no weed control available, it was a case of putting something in to give the clover a chance,” he said. And it worked.
“The red clover established extremely well and produced a quality sward. Now in its fourth year, the nutritional analysis remains high with the cattle finished on silage alone, achieving a liveweight gain of 0.9 kg/day.
“Although we planted the barley/pea crop solely to help the red clover establish and, therefore, cut it relatively early, we still gain some good bales from it.”