Establishing a Grass Clover Sward

Both fertiliser manufacture and its use release greenhouse gases implicated in climate change.

Using a grass clover sward can  help to reduce nitrogen applications, making full use of nutrients on the farm whilst maintaining farm profitability. Better targeted nitrogen applications can help to improve the farm carbon footprint and reduce diffuse pollution risks.

These top tips could help you  establish grass swards which have the capacity to improve production efficiency whilst minimising the long term cost of purchased inorganic nitrogen.

Benefiting the farm business

The single consistent message from the climate change focus farm programme is that efficient farming systems cut the quantity of  greenhouse gases emitted per unit of food produced.  In grass based systems, the production efficiency is geared to the capacity of the grass to maximise livestock production.

Addition of clover to grass swards can reduce the need for inorganic nitrogen applications, so saving money for the farm business whilst maintaining production levels and reducing the farm carbon footprint.

The single consistent message from the climate change focus farm programme is that efficient farming systems cut the quantity of  greenhouse gases emitted per unit of food produced.  In grass based systems, the production efficiency is geared to the capacity of the grass to maximise livestock production.

Addition of clover to grass swards can reduce the need for inorganic nitrogen applications, so saving money for the farm business whilst maintaining production levels and reducing the farm carbon footprint.

P&K requirements for Grass Clover Establishment

Reseeding is an opportunity to get your soil analysed and correct any P& K imbalances and to make sure you are on target for pH. The table below provides nutrient recommendations for grass clover establishment (kg/ha) based on soil analysis results:

Phosphate should be applied directly but spring application of K should be restricted to a maximum of 80 kg/ha to avoid luxury uptake. Where undersown, use the cereal recommendation plus an extra 40 kg/ha of P&K.

Top tips for establishing a grass clover sward

1. Direct reseed as opposed to under-sowing with a cereal crop.
2. For grass and clover aim for a pH of 6. Where cereals are grown in the rotation lime to an average of 6.2.
3. Allow for 4-6” of regrowth on an old grass sward or the cereal stubble to green up before applying a glyphosate (Roundup spray). Plough 10-14 days after the spray is applied.
4. Apply lime and straight phosphate to the ploughing and cultivate to produce a fine seedbed in good soil and weather conditions.
5. Roll before sowing to firm seedbed and ensure good contact between grass seed and the soil.
6. Based on soil analysis results, broadcast any additional fertilisers. If soil is at the high end of moderate, or has a high phosphate and potash status, there may be no need to apply compound fertiliser at sowing if slurry, manure, compost or digestate has been spread.
7. Sow the grass and clover mix and roll.
8. Once the grass has started to tiller and the clover has one to two trifoliate leaves, assess the weed population. If no problem weeds are visible, leave until grass can be grazed off by stock, preferably sheep. Where problem weeds are present, seek the opinion of a grass/clover specialist before using a herbicide. Examples of problem weeds are seedling docks, thistles and chickweed.
9. Graze grass in its first year and then use an alternative cutting and grazing system in fields which are not too steep to cut.
10. Where under-sowing with a cereal crop is the only option, additional management guidelines should be considered (see box below).

Maximise production post reseeding

• Match stocking rate to production potential.
• Cut at 50% ear emergence for young stock and later for suckler cows. Its easier to manage where grass is conserved as bale silage.
• Cut and graze in alternate years.
• As a rule of thumb, apply half to two thirds as much potash as you apply of nitrogen to cut grass. Remember a grass/clover silage producing 150 kg/ha (120 units/acre) of nitrogen still needs at least 75 kg/ha potash to replace crop offtake. A nutrient budget will help you plan nutrient additions and maximise both production and profit.

Under-sowing with a Cereal Crop