Last week, we reported that clover scoring was being carried out on the Footprint Farms.
This is to help to inform decisions on artificial nitrogen use on-farm.
Depending on the distribution of clover across a field, nitrogen (N) management can change.
If a field has a clover distribution of 70% for example, artificial nitrogen use could be cut once growth picks up and temperatures rise.
If the distribution is below 40%, the farmer either needs to put on high fertiliser N rates or reseed and include clover in the sward.
Over-sowing could be an option at 40-70% distribution. If the distribution is over 70%, artificial nitrogen could be cut from this paddock in mid-April or early May, when growth rates are up.
Assessing the distribution involves walking fields or paddocks and throwing down a quadrat. If there is one stem of clover in the quadrat or the quadrat is full of clover, that area is marked as having clover. The clover content can also be assessed.
Figures 1 and 2 show a walking pattern to follow when throwing the quadrat which covers the field. The quadrat should be thrown randomly every 20-30m.
Figure 3 then shows an example of a map that can be developed to record the clover distribution.
Figure 3 shows that the quadrat was thrown 42 times across the field. Ten times out of 42 there was no clover at all in the quadrat. This equates to a clover distribution of 76%. So, this field could be left without nitrogen in the coming weeks.
James Humphreys of Teagasc has explained that it will take the field time to adjust, but if the clover is distributed evenly across fields, it can recover and begin to yield similarly to a paddock receiving high N rates.
Figure 4 shows an example of the same field, except this time the clover distribution is just 43%.
This field would need to be over-sown or reseeded to improve the clover distribution before any adjustments could be made to nitrogen rates.
Results so far
So far on the Footprint Farms, results are very variable. We will publish these results when we have a better sample, but clover distribution is ranging from 14% to 92%. The good thing is there are paddocks with good distribution on all farms. This means there is an opportunity to try cutting back on nitrogen on all farms so far and to focus attention to the fields with low clover contents.