Increasing the content of clover in swards continues to have a focus in 2023, as farmers look to reduce their need for chemical nitrogen (N) on farms.
There are two methods that can be used to increase the clover content in swards: Full reseed or oversowing.
In paddocks that are new swards and have a low weed burden, oversowing is an effective way of increasing the clover content.
Clover seed is in short supply this year, with the lack of seed available due to a number of reasons, a large factor being poor harvests in New Zealand changing it from a net exporter of seed to a importer of seed.
This may mean that it could be difficult for many to get their hands on straight clover seed.
For full reseeds however, there will continue to be clover seed within grass mixes.
Clover
For anyone that does have straight seed and is planning on incorporating it into existing swards this year, it’s to get moving.
For clover seeds to germinate they requires light, moisture, good soil fertility and pH of 6.3 – but 6.5 is ideal.
Oversowing is an effective way of getting clover into these existing swards, but this only works at certain times of the year.
It should also be only done on paddocks that have a low weed burden.
On most farms, oversowing will not work after mid-May as the soil will become too dry and there won’t be enough moisture for the seed.
So paddocks that you have picked for oversowing this year need to be done over the coming weeks when conditions allow.
Management
The management of the clover post-sowing is probably the most challenging part of establishing clover in a paddock.
These paddocks need to be managed differently to all the others over the weeks/months proceeding sowing.
Light is needed by the plant so these paddocks need to be grazed at lower covers to allow light down to the bottom of the sward and stop the clover from being crowded out by the already established grass.
Meaning that for a number of weeks/months after sowing these paddocks need to be grazed at 1,100kg of dry matter (DM)/ha for three rotations after sowing.
You should also avoid the harvesting of silage from these swards, they need to be closed late in the final rotation and grazed early in the following spring.
It will also be eight to 12 months before chemical N levels can be reduced in these swards.