1. Leaving Certificate Agricultural Science
Grassland Management
H. Jones, St. Columba’s College

2. Sowing Leys Direct Sowing Best and most reliable way to obtain a ley.
The seedbed is prepared by ploughing and harrowing.
It should be very fine, finer than that for cereals.
Fertiliser should be broadcast and worked in during the final seedbed preparation.
The seed is sown using a combine drill, in lines 10cm apart and 2cm deep.

5. Sowing Leys - 2
They may also be broadcast over the soil and covered over using a chain harrow.
The land should be rolled after sowing to improve seed – soil contact and better germination rates.
Spring sown leys should be sown before May 1st due to the risk of drought.
Autumn sown leys should not be sown after Mid – September.

6. Sowing Leys - 3 Undersowing
Undersowing is used by farmers who employ tillage / grass rotations.
The grass seeds are grown with the tillage crop, usually a spring cereal.
Over the summer the two crops grow together and after harvesting, the grass takes over.
The land should be autumn ploughed and the seedbed prepared in the usual manner.
The grass is sown directly after the cereal (using a drill) and then the land is rolled.

9. Sowing Leys - 4
Spring Barley is the most suitable “nurse crop” as the competition between the two crops is less due to short straw and early harvesting.
Lodging is a problem with this method, so N application should be lessened by 30%.
Tillage yields are reduced using this method also.
Undersowing grass with arable silage (oats / vetch) is good farming practice.
The silage is cut early and the grass has a good chance of establishing itself.

10. Sowing Leys - 5 Direct Drilling
This technique involves drilling seeds into unploughed ground.
The drilling machine cultivates a small strip of soil and sows the seed in it.
No problems occur if direct drilled into stubble.
But if direct drilling into grassland, problems and/or competition can occur.

13. Sowing Leys - 6
The grassland should be grazed bare or mown and killed with a herbicide before direct drilling.
Slug pellets and fertiliser are added with the seed in order to help its establishment.
Direct drilling is most successful on shallow soils where ploughing is difficult.

15. Sowing Leys - 7 Stitching In
This system is almost the same as direct drilling, except the old sward is not killed.
The seed is drilled using a similar drill, along with slug pellets and fertiliser.
If the seeds establish themselves then they become the dominant species in the sward.
This system is not as predicable as direct drilling and the old sward can often win out.

16. Sowing Leys - 8 Slurry Seeding
Grass is sown as in direct drilling then covered in slurry.
Grass seeds can also be mixed with slurry before being spread on ploughed or stubbled land.
Grass grows strongly due to the presence of large quantities of organic matter.

18. Grassland Establishment
This refers to the development of the seedlings into a thick, densely packed pasture.
The most significant process in the establishment of a good sward is tillering.
Tillering is promoted by damage to the main shoots of the plants.
Newly sown pastures should be lightly grazed to encourage tillering and promote growth.

19. Grassland Establishment - 2
The best animals for this are sheep or calves, as cows would damage the crop.
This works well for spring sown grassland (not under-sown), as the land is dry when grazed.
Annual weeds can be controlled by grazing or topping, as tillering is then promoted and the weeds get little chance to establish themselves.
Perennial weeds like dock can be partially controlled by topping, but a selective herbicide may be required in extreme cases.

20. Grassland Management Good Grassland Management involves the following:
Finding out the amount of herbage required.
The application of ample fertiliser to achieve this.
Maximising the DMD of the sward by managing grazing and conservation.
The amount of herbage output required is calculated by the amount / type of stock on the farm.
Generally 1 livestock unit consumes 12 tonnes of herbage dry matter per year.

21. Fertiliser Requirements
The amount of fertiliser applied to grassland greatly depends on the grazing level and the level of establishment.
Fertiliser should be applied to newly established grassland where grazing is light, in the following proportions:
N – 48 kg / ha
P – 20 kg / ha
K – 38 kg / ha
Intensely grazed pastures should receive additional fertiliser as outlined by Teagasc.

22. Fertilizer Requirements
Land set aside for silage or hay should also be fertilised in advance of each harvest.
Hay is only cut once over the grazing season while silage can be cut repeatedly.
The following is recommended by Teagasc:
Crop
Fertilizer Application (kg / ha)
Silage
1st Cut
N P K
2nd Cut
3rd Cut
1 Cut
2 Cuts
3 Cut
Hay

23. Managing Grazing
Good grazing management requires young leafy digestible grass to be available for grazing at all times.
An efficient system of rotational grazing allows the farmers achieve this.
There are various systems available including Paddock Grazing, Strip Grazing, Block Grazing, Set Stocking, Creep Feeding and Mixed Grazing.

24. Grazing Management - 2 Paddock Grazing
Paddock grazing is the most efficient form of rotational grazing, whereby 20 – 25 paddocks are created using electric fencing.
The paddocks are created to suit the herd, using the rule: 120 cows will graze 1 ha of young leafy grass in one day.
The herd graze one paddock per day in a rotational manner.
Nitrogen is applied to the paddocks as soon as they are removed.

25. Grazing Management - 3
By the time they return to the paddock, the grass should be at the height of its digestibility.
This system can be quite expensive but is widely used on dairy farms.
Silage fields are usually kept independent of the paddock system, as the small areas may be difficult to cut.
Calves & replacement heifers graze any replacement grass.
Paddock grazing systems are sometime called rotational grazing systems

27. Grazing Management - 4 Strip Grazing
This system involves the use of a movable electric fence, to give the stock a fresh strip of leafy grass per day.
Grass strips are fertilised in the same way as the paddock system.
A back fence should be used however, as to allow the grass recover sufficiently.
This system is cheap, but requires a lot of labour time and is therefore rarely used by itself.

29. Grazing Management - 5 Set Stocking
This is simplest, cheapest but least effective form of grazing management.
It simply involves allowing the stock free access to all areas throughout the grazing year.
This allows set – stocked areas to become patchy, with areas of highly un-productive grasses evident.

31. Grazing Management - 6
Set stocking has a number of particular advantages.
Fencing and water troughs can be kept to a minimum and the continuous general nature of the grazing encourages a close dense sward that is usually rich in clover.
Set stocking is often practices in a modified way with beef, dairy and sheep systems utilising a few large blocks of pasture on a farm ( Block Grazing).

32. Grazing Management - 7 Block Grazing
This system is the most common system used in Ireland, as it is cheap, effective and low on labour.
It involves the division of the grazing area into blocks that provide grazing for 7-8 days.
Pasture management can be improved by using strip grazing in each block.
Larger blocks can be set aside for silage once or twice a year.
This system is cheap and is suitable for dairy, beef and sheep grazing.

34. Creep Feeding
This system involves allowing young animals access to the best grass by means of a fence with a hole only large enough for a calf or lamb.
The calf or lamb can “creep” through the small opening to the good grass but the adult cannot.
This allows the young animals to get the best grass, avoid worm infection and still allows the animals to suckle their mother.

36. Leader - Follower
This basically involves allow the younger animals onto a paddock, strip or block before the adults.
This again allows the younger animals to get the best grass and avoid picking up intestinal diseases.
It involves less “set up” than creep feeding.
It is common practice on dairy farms, when replacement heifers lead the main herd.