Currently only 5% of agricultural grassland is reseeded and permanent grass leys plays a significant role in UK production. Well managed grass is the lowest cost feed for ruminants. Renewing swards regularly is important to maximise poductivity and maintain feed quality.
As grass varieties are constantly improved, reseeding can produce over £500/acre potential extra milk production. Using new improved varieties can give 33% more yield than a typical five year ley. Over the next four years, DM yield will be 10% higher.
The benefits of a new ley can last many years over an existing one. However, over time these benefits will decline. The rate that a ley declines will depend on:
Nutrition - Maintaining the swards nitrogen, phosphate, potash and sulphur requirements.
Soil health - Maintaining correct soil pH and avoiding compaction.
Weed Control - Maintaining an appropriate weed control programme.
Grassland Management - reducing ingress of native species (weed grasses) which are of lower production and nutritional quality.
The amount of ryegrass (or other sown species) is a better indicator for a need to reseed than the actual age of the ley. As the ley increases in age, the yield potential falls to as much as 50% after five years. Reseeding should be considered before sown species fall below 50%. Weed grasses e.g annual meadow grass make up the rest. These offer less yield, poor feed quality and low response to nitrogen.
Although there is obviously a cost in reseeding this will be quickly gained back in extra milk or meat produced. It is also important to address other issues that might reduce output, before reseeding, to ensure maximum benefit.
The amount of weed grasses in the sward increases over time reducing productivity. (Sown species decrease at about 10%/year).
The potential yield losses from weed grasses compared to perennial ryegrass can be seen below:
The perennial ryegrass and weed grass response to nitrogen is shown below:
4000kgDM/acre x extra 1 MJ/kgDM quality (11MJ/kgDM ‘v’ old ley@ 10MJ) = 4000MJ/acre extra
Plus yield 20% DM/acre = 800kgDM@11MJ/kg DM = 8800MJ/acre
At 40p / L = £966 / acre additional milk
By selecting a recommended listed grass mix you will benefit from scientifically proven yield benefits and allows you to capitalise on the strengths of different species.
Using the recommended list provides information on the best performing grasses and clovers available. Varieties on the list have been independently tested.
The recommended list allows selection for quality:
Yield and quality performance - Dry matter and energy.
Field performance - Disease resistance and persistence.
Feed performance - Grass fibre (NDF), cell wall digestibility (CWD), water soluble carbohydrate (WSC) and protein.
Select a mix for your system e.g silage only, grazing only or dual purpose.