White clover will become more and more attractive to farmers as the fertiliser prices continue to rise to new heights year on year. Stated Dr James Humphreys, Senior Research Officer in Teagasc, Moorpark at an Agricultural Science Association (ASA) recent technical event on the Nitrates Directive.

In a detailed presentation to ASA members in attendance on efficient use of nitrogen on grassland Dr Humphreys said: “There has been an awful lot of interest in white clover particularly in recent years with the rising cost of fertiliser.”

He said: “Research has shown fixation rates of up to 200kg of nitrogen per ha/ year are achievable with white clover. We have been looking at it over 15 years. We looked at all the different systems during that time.”

“We recently published a paper which was an economic comparison between fertiliser nitrogen and white clover. Of course what we found was it varied with the price of milk and price of fertiliser.

“What we have seen is that fertiliser prices have continued to increase since early 90’s. During the mid-90’s through to 2005-2006 it was always more profitable to have a fertiliser based nitrogen system. That is assuming REPS was not part of the story.”

“Then in more recent years white clover systems are becoming more attractive. Because of the rising cost of fertiliser. What we have seen recently is a very high milk price, so that has meant fertiliser is still more profitable.”

Humphreys commented: “But you could see a situation in the future where white clover will become more attractive. It is definitely something that should be on all beef farms.”

Making efficient use of fertilizer N using White Clover

Humphreys remarked: “There is a large potential to cut fertilizer N use of farms. In some cases it can be halved. We can look at fixation levels of 100 to 200 kg N per ha per year. Of course it is variable, which is one of the problems with clover.”

“White clover can be used at stocking rates up to 2.5 LU per ha. Low fertilizer nitrogen input and tight grazing are important. There is a bit of a conflict between using high rates of nitrogen and making use of white clover.”

Humphreys outlined: “It can be introduced into the sward by reseeding, over-sowing or simply by management, with tight grazing being very important. Generally it suits farms where a long grazing season can be achieved. If you are on the type of land were you had to close the ground up in October and that ground won’t be cut for silage again until the end of May the following year. That type of situation doesn't suit clover that well.”

He added: “In generally it is suited better to dryer soils, due to the fact white clover is sensitive to shading over winter and poaching damage.”