Summer Beef Series is in conjunction with Teagasc’s DairyBeef 500 campaign
As chemical fertiliser prices reached new highs last year, many beef farmers looked at ways of reducing the amount of fertiliser that they applied on their farms.
Since early 2022, interest in red clover silage swards has risen exponentially due to the fact that a red clover sward has the potential to fix 150-200kg N/ha, releasing it to other plants and reducing the need for nitrogen fertiliser.
Due to its growth habit, red clover grass mixes suit swards targeted for silage, and under good management, it is likely to persist at good levels for five-seven years.
Yields of 15-18t DM/ha are obtainable under zero N systems which is comparable to yields of high chemical N applications.
The resulting silage produced from red clover also has the potential to provide additional levels of animal performance in terms of liveweight gain, derived from the extra intake potential associated from the feed.
Red clover
DairyBeef 500 farmer Aidan Maguire incorporated red clover silage onto 4ha in 2022. The first 2ha went in on May 1, 2022.
Aidan harvested three cuts of silage and achieved one grazing from this field.
This year, the sward was grazed in good conditions in mid-February. After grazing, it received 3,000gal of slurry to the acre and it yielded 11 bales of silage to the acre with no chemical fertiliser.
The plan is for a further three cuts of silage to be taken off this field throughout the year at intervals of 6-7 weeks.
So far this year, the red clover silage had higher yields than the conventional silage at a greatly reduced cost due to lack of chemical N.
At harvesting, Aidan Maguire treats the red clover sward the same as the grass-only swards.
”I don’t lift the mower up and if the weather permits, I will ted it out and leave it on the ground for 24 hours. The only difference is that I don’t spread any chemical fertiliser which is saving me €50/ac of fertiliser at today’s price,” he explained.
Another big advantage of red clover is its ability to support higher levels animal performance when fed during the winter.
The extra weight gain from red clover silage is generally attributed to increased intake. Provisional results from Grange and other studies indicate that weanlings are achieving higher daily gains on the back of increased dry matter intakes.
Aidan concurs with the research and found animals performed really well on the red clover silage with all of his bullocks finished at an average of 23 months.
“The only problem that I had with the red clover silage over the winter was that I didn’t have enough of it,” he said.
Saving on fertiliser
Even though fertiliser price has come back in the last couple of months, Aidan is so impressed with red clover, he sowed another 2ha of a red clover mix in early May.
Before sowing, it got two bags of 10-10-20 and lime. It then gets two runs of a power harrow and is sown with a tine harrow and seed box.
The sowing rate Aidan uses is 10kg of ryegrass, 4kg of red clover and 1kg of white clover.
Red clover does have limitations – it is unsuitable for intensive grazing due to the risk of physical damage to the plant by grazing animals.
The recommendation is to graze light cattle for a short period in the backend to clean up before winter if ground conditions allow. Persistency can also be an issue, with commercial farms observing a lifespan of 3-4 years.
However, by using a seed mixture that contains 4kg red clover along with 8kg good perennial ryegrass variety and 1kg of a large leaf white clover, the need for reseeding after the red clover dies out will not be warranted as a good ryegrass/white clover sward will be left in place.
The low dry matter (DM) nature of the crop can cause challenges when ensiling, so if possible, a 24-hour wilt in good conditions is needed.
Establishing red clover swards
- Red clover is best sown as part of a full reseed from April to late July in well-drained, fertile soils;
- Soil test. Target a pH of 6.3-6.5 and Index 3 for P & K;
- Spray off the old sward with glyphosate;
- Apply lime as required;
- Seed Bed – a fine, firm seed bed is required to ensure contact with soil, which is essential to seed establishment. The use of a roller prior to and after sowing is recommended;
- Can be drilled at 0.5-1cm deep or broadcast. Sow seeds no deeper than 1cm, to ensure seedlings have sufficient energy to emerge;
- Apply P and K in line with soil test results;
- Apply a clover-safe weed spray approximately 5-6 weeks after establishment or when docks are the size of a €2 coin; do not spray if growth conditions are poor;
- Graze swards lightly in the autumn of the sowing year. Avoid grazing in wet weather.