A number of farmers have been asking what is the right thing to do regarding fertiliser this autumn.

Many of these farmers in the dry parts of the country have decided not to spread fertiliser for a number of weeks, while others are concerned about costs.

There are two important things to look at regarding fertiliser. The first, and maybe the most important, is availability next spring.

I know of a lot of dairy farmers who have forward-bought 40% to 60% of their annual requirements for next year already.

Scarce and expensive

The fear is that with rising gas prices and some fertiliser factories shutting down, fertiliser will be more scarce next year than it was this year and it could be even more expensive.

The flip side to that argument is that it is not cheap now, so if fertiliser does end up dropping in price, the farmer will be left carrying the cost.

The question around fertiliser is not necessarily can you afford it, more so can you afford to farm without it

As a farmer said recently, the question around fertiliser is not necessarily can you afford it, more so can you afford to farm without it.

For the majority of dairy farmers, the answer is no.

Secondly, in terms of fertiliser for this autumn, I would look at it in a number of ways.

On farms with a decent stocking rate that need to grow grass for the autumn, fields that have not been that badly affected will probably need between 20 and 30 units of N/acre this autumn.

On fields that have been burnt from the dry spell, they will probably release a good amount of background nitrogen, so half this rate is probably sufficient, such as 10 units to 15 units of N/acre.

Release

This is because after the rain, there will be a release of nitrogen from the soil, which was not used for plant growth up to now.

How much nitrogen that will be released is hard to quantify and probably depends on how severe the dry spell was.

It would be wasteful to apply too much expensive chemical nitrogen now, particularly if there will be a release of sufficient background nitrogen for free.

It is also important not to over-play how much background nitrogen will be released. For farms that continued to grow at a rate of 30kg to 40kg and above, the release of background nitrogen will be small enough.

High clover content

Of course, fields that have a high clover content won’t need any chemical nitrogen because there will be enough nitrogen in the system from the clover.

Because most farmers are well behind target in terms of grass supply on farms, there is a lot of supplement being fed now and over the next few months.

So even though fertiliser is expensive, if you get a good response to it in terms of grass growth, it makes sense to spread nitrogen.

However, there is always the risk of losses and this is greatest in the autumn, so keep this in mind when deciding on rates.