The Teagasc clover walks got underway earlier this week and Agriland attended the farm walk on Kevin Moran’s farm near Tuam, Co. Galway.
On the walk, attendees heard Michael Egan from Teagasc and Kevin Moran discuss the establishment of clover in grass swards.
Soil fertility
Speaking at the event, Michael Egan told the farmers in attendance that the objective of the farm walk is to discuss the establishment and management of clover.
“When it comes to establishing white clover on farms soil fertility is key,” Michael said.
“Clover requires soil indexes of three for phosphorus (P) and potassium (K); it also requires a soil pH of 6.5.
“The higher pH, the better it is for white clover. This higher pH is essential for root nodules.
“So identifying paddocks with high levels of soil fertility is important for establishment of clover.”
Methods
Commenting on the methods that can be used for white clover establishment, Michael said: “You have two methods of establishment: Reseeding and oversowing.
“In terms of reseeding we are not changing the general practice, we are not doing anything different to a grass only reseeding the sward – the only difference is you are going to have 1.5kg or 2kg of white clover in the mix/ac.
“The key thing you want to be careful of when doing a full reseed is the sowing depth.
“White clover seed is very, very small; because of that, it has a very low-energy reserve in the seed.
“So if the seed is buried too deep, it won’t have the energy to push the seed up through the soil and it won’t be able to germinate.
“You are looking for a sowing depth of 10-12mm. The majority of sowing methods are not as issue.”
It can be an issue however, with your Atkinson type machine or Unidrill that cuts the slit and buries the seed down, Michael noted.
Continuing he said: “Oversowing is the second method. [With this] you want a sowing rate of 2kg/ac – the higher rate is due to a higher failure-rate from this method.
“If we want to get clover on our farms, coming from a very low or zero-clover content to a high level in a short period of time, there has to be a two-pronged approach.
“Although oversowing is less successful, it does work well if it is done right and done at the correct time of the year.
“April and very early-May is the ideal time to oversow clover. This is because you need sunlight and moisture. If you wait until June or July it is too dry and the seed won’t be able to penetrate down into the hard soil.”
Best paddocks
When oversowing it is important that you select the most suitable paddocks, with Michael saying there are four things to look out for:
- Soil fertility;
- The level of rye grass in the sward;
- A low level of weed burden; and
- Light, for the clover at the bottom of the sward.
“Two of them can be corrected, two of them can’t really. The level of weeds in the sward can be corrected and soil fertility, although that may take longer,” said Michael.
‘It is very hard to reduce the level of weed-grass content or dense butty swards and the level of rye grass in it – generally, they go hand in hand.
“Pick your paddocks for this year and paddocks that can be corrected and oversowed next year.
“If you spray weed now, it will be too late to sow clover this year – so pick the low hanging fruit first and then go forward with a clear plan.”
Clover management
Michael recommended not planting too much clover at one time as it involves a lot of management.
“Doing too much of it at one time makes it very hard to manage,” he said.
“We want to be as aggressive as possible, but not to be stupid either and do too much that we can’t manage.
“So, reseeding somewhere in the region of 10%; it is going to vary year on year. For oversowing the most we are going to say for any one farm is between 15% and 20%.
“This is because if you have 40% or 50% of your farm that needs to be preferentially managed, it is impossible.”
Continuing, Michael said: “Whether it is oversowing or a full reseed, the management of the sward is the same for the remainder of the year.
“The timing of your post-emergence is the most important thing. In an oversowing scenario, we want to reduce our nitrogen (N) by 15kg N/ha for two months.
“‘The reason for this is to slow down the grass growth rate slightly, to give the clover seed a change to germinate and persist in the sward.
“We are not going with zero, because we want to maintain grass quality. We just want to reduce growth rate for two months then increase back to normal rates.”
Grazing management
Kevin then outlined his grazing management of clover swards: “For the first four to five grazings after oversowing we graze them at 1,000kg of dry matter (DM)/ha to 1,100kg of DM/ha.
“Once you get to August you can see the clover is well established, but one thing I have found is you cannot carry a heavy cover in those paddocks over the winter.
“Graze the paddocks you have reseeded or oversown in the final third, so they have a lower cover over the winter,” Michael said.
“When you come into the spring they will have a lower pre-grazing cover, but you should graze them as early as possible.
“It takes the clover plant 12 months for it to fully establish, so you want to give it as much preferential management – and grazing management is key.
“The lower N will reduce grass growth to give your clover a better chance, but hitting it at the correct covers is more important.
“Getting light down to the base of the sward is important; without light the clover seed will struggle to establish itself against an established sward.”