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Grass Growth Prediction - more farmers now predicting


The number of farms where grass growth predictions are conducted using the Teagasc MoSt Grass Growth Model has increased to 78 in recent weeks. The increased number ensures a larger diversity of farms and better coverage across the country. Researcher Dr Elodie Ruelle is leading the project.

Figure 1: Map representing the grass growth prediction for the 78 farms. Each dot corresponds to the location of a farm, and the corresponding number the predicted growth (kg DM/ha) for the next 7 days for this farm. Yellow numbers correspond to Teagasc research farms and white dots to commercial farms.

How does the prediction work?

Grass growth is predicted using the Teagasc MoSt (Moorepark St Gilles) Grass Growth Model. The grass growth predictions are specific for each farm and are depend on the management of the farm in terms of:

  • grazing
  • nitrogen fertiliser rate applied and date of application
  • the past and forecasted weather - rainfall, temperature and solar radiation”.

The live grass growth project started in 2018, a difficult year with cold weather in the spring and a summer drought. It highlighted the requirement for farmers to know what grass growth would be in the following week. In 2018, the grass growth prediction started on 5 Teagasc farms, this was extended to 30 farms, mostly commercial, in 2019, and from this month to 78 farms covering almost all of the country.

Where are the predictions accessible?

The grass growth predictions are available weekly in the Grass10 newsletter, the Irish Farmers Journal and on Met Éireann twitter, as well as on the Farming Forecast every Sunday on RTÉ One after the One O’Clock News.

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How useful are the predictions? 

Head of Grassland Science in Teagasc, Dr Michael O’Donovan added; “the feedback from farmers is very positive with the prediction allowing them to make management decisions based on the future instead of on last week’s growth. Nitrogen fertiliser decisions can be made easier based on the predicted farm growth. We see this model as a key strategy of reducing nitrogen surplus on farms through better grazing management decision making”.

The grass growth predictions are currently sent in the form of a precise number, either corresponding to a farm, or the county average. The reality is that each farm is different. This is why the trend of the grass growth prediction (increase or decreasing compare to the previous week) is more important than the actual number. A specific farm could be consistently growing less than the prediction, but the overall trend should be similar.

The grass growth predictions are available on the landing page of PBI, in the Ireland map. They will be available in the future directly from PBI. However to have their farm’s grass growth predicted, farmers will have to enter at least 25 grass covers a year and will have an up to date record of the grazing/silage cutting, as well as nitrogen fertiliser applied, to ensure accurate predictions.

Go to Pasturebase Ireland 
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