Clover scoring is a useful tool to help farmers determine the clover levels on their farms, this can help to determine whether to reseed paddocks or over-sow clover to cut back on artificial nitrogen (N) use.
On 2 July, the Irish Farmers Journal carried out clover scoring on a range of paddocks on the farms of Barry Powell in Nenagh, Co Tipperary and Martin Crowe in Doon, Co Limerick. With the cold and wet weather we have experienced over the last number of months, clover has been struggling to grow and perform in the sward.
Swards with a 40%–70% clover distribution can be over sown to help reduce nitrogen requirements.
Clover grows only when soil temperatures exceed 8°C, while grass can germinate at 5°C. If the temperature is too low for clover, grass will dominate.
Clover levels
Nitrogen (N) application can be reduced or stopped based on clover levels; if clover covers 70% of a field, artificial N can be eliminated. However, this year’s unusually cold and wet weather could hinder grass growth if N is reduced too early.
Conversely, growth support from nitrogen fertiliser will still be required if the field’s clover distribution is less than 40%. It is best to over-sow swards with a 40%-70% clover spread in the spring or early summer.
Stitching in clover is often the best method of establishment where clover distribution is over 40%, but a full reseed is needed where clover distribution is below 40%.
Sheep grazed swards are denser, drilling or harrowing to stitch in is better.
Barry Powell, Nenagh, Co Tipperary
Barry’s dairy farm had mixed levels of clover distribution across the paddocks. The average clover on the farm was 63%, this ranged from 28% to one field having 100% clover distribution.
The field that showed the lowest clover (28%) has not been reseeded and is an old pasture.
Martin Crowe's farm is on high ground and is struggling with poor growth conditions.
There were some fields where the clover was just starting to grow and if the weather improves this should help with growth.Two of the paddocks that had been reseeded last year showed high levels of clover between 75 and 86%.
Clover scoring has assisted Barry with deciding what paddocks he will try to over-sow with clover this year.
As it is getting late in the season, the opportunity for doing a full reseed could be hindered, so over-sowing could be the best option at this time.
Martin Crowe's farm is on high ground and is struggling with poor growth conditions.
Martin Crowe, Doon, Co Limerick
Martin has been focusing on incorporating clover into his swards over the last number of years. The clover dispersion ranges from 33% to 77% across a selection of the paddocks on Martin’s dairy farm.
A paddock with 50% clover was over -sown two months ago, which will allow for a higher distribution next year once it has emerged.
The average clover distribution is 57%; this has enabled Martin to cut down on the level of nitrogen used; in one field that has not received any N in the past five years there is 57% clover distribution.
Martin highlighted that he struggles to suppress weeds, such as spear thistles, docks and ragwort while protecting the clover in the swards.
Topping is used to control the weeds but after two years Martin begins to spot spray before having to spray the field and start reseeding again.
ProClova is a type of herbicide that kills weeds in new leys and established grasslands while protecting clover. It can be used from March to October.
Clover score your farm
In this method of clover scoring, we assessed clover distribution rather than clover content. The fields are walked in diagonal lines and the whole field is covered and a quadrant is thrown randomly every 20 to 30 metres.
If clover is found within the quadrant, it is marked, and the quantity is noted for reference. Once clover is present in any amount then it is marked on the field map. Once N is taken out this clover should start to fix more nitrogen and increase in amount. When clover is well-established and dispersed throughout the field, it should start to produce yields that are comparable to those of a paddock that gets a lot of artificial N.
For example, if the quadrant is thrown 12 times across the paddock and clover is absent in 3 of those instances, this indicates a clover distribution of 75% for the paddock.
Successful over-sowing
Paddocks that aren’t ready for over-sowing the first year should have their weed problems and soil fertility addressed before being over-sown the next year.For successful over-sowing, choose paddocks that have: optimal soil fertility (P and K index 3 or higher, soil pH 6.3).High perennial ryegrass content.Open or low-density swards.Low weed content.
Clover scoring is a useful tool to help farmers determine the clover levels on their farms, this can help to determine whether to reseed paddocks or over-sow clover to cut back on artificial nitrogen (N) use.
On 2 July, the Irish Farmers Journal carried out clover scoring on a range of paddocks on the farms of Barry Powell in Nenagh, Co Tipperary and Martin Crowe in Doon, Co Limerick. With the cold and wet weather we have experienced over the last number of months, clover has been struggling to grow and perform in the sward.
Swards with a 40%–70% clover distribution can be over sown to help reduce nitrogen requirements.
Clover grows only when soil temperatures exceed 8°C, while grass can germinate at 5°C. If the temperature is too low for clover, grass will dominate.
Clover levels
Nitrogen (N) application can be reduced or stopped based on clover levels; if clover covers 70% of a field, artificial N can be eliminated. However, this year’s unusually cold and wet weather could hinder grass growth if N is reduced too early.
Conversely, growth support from nitrogen fertiliser will still be required if the field’s clover distribution is less than 40%. It is best to over-sow swards with a 40%-70% clover spread in the spring or early summer.
Stitching in clover is often the best method of establishment where clover distribution is over 40%, but a full reseed is needed where clover distribution is below 40%.
Sheep grazed swards are denser, drilling or harrowing to stitch in is better.
Barry Powell, Nenagh, Co Tipperary
Barry’s dairy farm had mixed levels of clover distribution across the paddocks. The average clover on the farm was 63%, this ranged from 28% to one field having 100% clover distribution.
The field that showed the lowest clover (28%) has not been reseeded and is an old pasture.
Martin Crowe's farm is on high ground and is struggling with poor growth conditions.
There were some fields where the clover was just starting to grow and if the weather improves this should help with growth.Two of the paddocks that had been reseeded last year showed high levels of clover between 75 and 86%.
Clover scoring has assisted Barry with deciding what paddocks he will try to over-sow with clover this year.
As it is getting late in the season, the opportunity for doing a full reseed could be hindered, so over-sowing could be the best option at this time.
Martin Crowe's farm is on high ground and is struggling with poor growth conditions.
Martin Crowe, Doon, Co Limerick
Martin has been focusing on incorporating clover into his swards over the last number of years. The clover dispersion ranges from 33% to 77% across a selection of the paddocks on Martin’s dairy farm.
A paddock with 50% clover was over -sown two months ago, which will allow for a higher distribution next year once it has emerged.
The average clover distribution is 57%; this has enabled Martin to cut down on the level of nitrogen used; in one field that has not received any N in the past five years there is 57% clover distribution.
Martin highlighted that he struggles to suppress weeds, such as spear thistles, docks and ragwort while protecting the clover in the swards.
Topping is used to control the weeds but after two years Martin begins to spot spray before having to spray the field and start reseeding again.
ProClova is a type of herbicide that kills weeds in new leys and established grasslands while protecting clover. It can be used from March to October.
Clover score your farm
In this method of clover scoring, we assessed clover distribution rather than clover content. The fields are walked in diagonal lines and the whole field is covered and a quadrant is thrown randomly every 20 to 30 metres.
If clover is found within the quadrant, it is marked, and the quantity is noted for reference. Once clover is present in any amount then it is marked on the field map. Once N is taken out this clover should start to fix more nitrogen and increase in amount. When clover is well-established and dispersed throughout the field, it should start to produce yields that are comparable to those of a paddock that gets a lot of artificial N.
For example, if the quadrant is thrown 12 times across the paddock and clover is absent in 3 of those instances, this indicates a clover distribution of 75% for the paddock.
Successful over-sowing
Paddocks that aren’t ready for over-sowing the first year should have their weed problems and soil fertility addressed before being over-sown the next year.For successful over-sowing, choose paddocks that have: optimal soil fertility (P and K index 3 or higher, soil pH 6.3).High perennial ryegrass content.Open or low-density swards.Low weed content. 
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