Yield
Monoculture of Red Clover may result in a lower yield per hectare if compared to when sown with suitable grass species.
Variety Choice
The highest yielding strains of Red Clover are called 'Double cut' varieties, which may be either tetraploid or diploid in nature.
The variety Altaswede provides one large cut per season, it is therefore known as a 'Single cut' variety. Normally it flowers approximately 10 days later than the 'Double cut' varieties and may also be either tetraploid or diploid in nature.
Tetraploid Red Clover
With larger leaves tetraploids are able to smother many grass species such as perennial ryegrass. Therefore, they need to be grown alongside grass species that match their characteristics. That means Italian or Westerwold ryegrass, both of which are strong enough to compete.
Sown thus, immediately categorises a ley to a persistence of 2 years. Leave them down for longer and the grass species die out leaving the Red Clover to dominate. A pure stand of Red Clover is around a third lower yielding than one which contains the aforementioned grass species.
Diploid Red Clover
Does diploid Red Clover persist longer? Some do, but the persistence of a Red Clover results from the selection of a persistent parent by plant breeders. Ploidy (tetraploid or diploid) is not really the deciding factor.
Seed
Seed size (Thousand Grain Weight; TGW) varies by seed lot and is influenced by variety as well as other factors. The TGW varies from 1.5 to 6.5 g which has a large effect upon the number of seeds found per 1.0 kg of seed.
Plants per m2
It is difficult to establish what is the correct target plant population per metre squared for a Red Clover sward. Although research has been carried out around the world over the last 100 years results are conflicting for many and varied reasons.
As a guide research suggests that 30 to 60 plants / m2 are required for “productive” monoculture swards. Therefore 15 to 30 should be the target for a 50:50 mixed swards containing competitive ryegrass species.
Sowing depth
Rolling pre planting is advised.
Clover seed is small and should be broadcast or drilled at a shallow depth.
The optimum seed depth is in the range 5-10 mm. It should never exceed 15 mm since sowing deep dramatically reduces successful establishment.
Persistence
Crops persist 2 - 3 years. It is the survival of the plant crown that determines it longevity. The crown can gradually deteriorate either becoming diseased, damaged by cutting, trafficking, or trampling by livestock.
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