By Thursday, the closed period for spreading chemical fertiliser will have kicked in and spreading chemical nitrogen and phosphorus will be prohibited.

Slurry can continue to be spread until 8 October this year, while farmyard manure can continue to be spread until the end of October.

In terms of grass growth and grass supply, most farms are well behind target for both, so the economics of spreading fertiliser now to boost grass growth applies.

This is because the extra grass grown by the fertiliser will displace silage and meal from the diet, which costs a multiple of grass grown by fertiliser.

That is not to say that all farms should be spreading fertiliser now to capture some of this extra growth.

Low demand

For many farms that have a low demand for grass or where extended grazing is just not going to be possible, then there is no point in spreading fertiliser in order to grow grass that may not be required.

So it is very much a decision that should be taken on a farm-by-farm basis based on current grass supply and future grass demand.

For farms with an identified need for extra grass, spreading between 15 units and 25 units/acre of nitrogen is close to optimum.

The amount of background nitrogen in the system that will be released after the dry spell is unknown.

So too is the long-term outlook for grass growth, so there is uncertainty over how much of the applied nitrogen will actually be utilised.

There is a risk that some of the nitrogen will be lost, so it makes sense to be prudent with application rates.

It’s important to remember that the main time for nitrate losses is in the late autumn when nitrogen built up in soils over the summer is leached in the autumn rains.