In 2020, Teagasc published mitigation measures to reduce greenhouse gas (GHG) emissions from agriculture and the introduction of clover was one of the measures referenced.
Environmental benefits of clover
According to the report, improved nitrogen-use efficiency, via optimising soil pH and extension of clover in pasture swards, would result in an 8% reduction in fertiliser use between 2021 and 2030. It has been highlighted that farms in derogation will be obliged to include white clover in their swards when reseeding in the future.
In addition to the benefits already mentioned, there are both sward and animal benefits from planting white clover in grass swards.
Research has shown, a grass sward containing 20% white clover will have a positive effect in terms of increasing animal production. White clover is a high quality and very digestible plant and it supports higher animal intake. Combined with the increased quality of the diet, animal performance will also increase.
Teagasc research has also shown that when comparing swards containing 30% white clover and applying 150 kg N to swards receiving 250 kg N with no clover, a similar level of total herbage production is achievable from both awards.
Thus, the nitrogen being fixed by the clover plant is offsetting the reduction in N applied. This supports high grass growth rates while reducing fertiliser bills on the farm which is deemed a win-win for the farmer and the environment.
Managed practices when introducing white clover seed
Clover likes fertile soil with good pH. In order for clover to establish effectively in the soil, a pH of 6.3-6.5 is optimum and therefore lime application in suboptimal pH soils is required prior to sowing clover.
Sowing white clover in a full reseed
- Sow 0.6 kg/ac or 1.5 kg/Ha naked or 1.0 kg/ac or 2.5 kg/Ha Coated
- May to early August
- Clover safe post-emergence spray is critical
Overseeding white clover into an existing grass sward
- Control weeds before you consider over-sowing clover
- Some herbicides have a residue of up to 4 months – so if sowing clover next year, now is the time to adapt a weed management policy in those fields. If you plan on sowing clover this year; check the residual time on the label of the product you are using or seek advice on a suitable weed control product.
- Ideally over-sow clover after silage harvest or a tight grazing
- Moisture is important and therefore its establishment will be less successful if sown when entering a dry period
- Soil must be visible, therefore do not over-sow where you have a thatch of grass
- Coated clover may be of benefit as it is generally a bigger heavier seed and therefore more likely to make soil contact
Fertiliser spreader will work
- Mix 1-2 kg clover with a bag of 0:7:30 per acre
- Only add clover to the spreader when you are in the field. Otherwise, there is a risk of the clover seed “settling” at the base of the spreader and thus you will not have an even spread of clover in the field
- Only do a maximum of 5 acres at a time
- Spread in 2 directions – up and down the field and then across the field
- Clover will not throw as far as fertiliser, so hence why sowing half rate in two separate directions will give a better chance of success
Post-sowing
- Graze the grass again about 10 days after sowing
- Do not apply N and ideally skip bagged N for the remainder of the year, but at least for 2 rounds
- Graze every two weeks or so for about three grazings to ensure light gets down to the base of the sward to aid clover establishment
Coated white clover seed option
Coated white clover seed can improve the establishment and productivity of white clover in both a full reseed and over-sowing situations. The coating used by Germinal on their white clover contains beneficial ingredients to aid faster germination and provide more energy to the seed. These include:
- Phosphorus to promote root growth and allow the clover plant to establish quicker, and better compete with grasses for soil nutrients
- Rhizobium inoculants to ensure rapid nodulation by rhizobium bacteria which will fix N for the clover and grass plants.
Coated white clover seed has been shown to produce seedlings with longer petioles and larger leaves. Additionally, the coating creates a larger seed size which is beneficial in terms of placing of the white clover in the seedbed as well as helping ensure a better chance of soil to seed contact in an over-sowing situation.
Watch: White & red clover webinar