During a very wet period last spring, a farmer said to me: “there’s only two places fertiliser won’t grow grass – in the bag and in the river.” Back then, any fertiliser spreading would have pretty much resulted in putting it from one into the other. Right now, the situation is a whole lot different, however.

The go-to fertiliser at this time of the year is urea. Pound-for-pound, urea, at 46% N, is a cheaper source of N compared to CAN at 27% N. However, to make the most of this price differential, conditions must be right. Soil temperature is the first thing. Anything over 5-6°C, ie the temperature at which grass begins to grow, is ideal. Moisture is also important. Approximately 10-15mm of soil moisture will help urea move into the soil and reduce N losses through volatilisation.

All in all, conditions would appear to be ideal for spreading. Damp conditions shouldn’t be an issue with the rain that fell earlier on in the week. Scattered showers are also forecast for the rest of the week and weekend which will only help to break down granules into the soil. In terms of soil temperature, Met Éireann charts show a range of between 7-9°C across the country, surpassing the 5°C requirement for spreading.

Going back to my opening point, with very little risk of leaching into rivers, it would appear that the only place fertiliser won’t grow grass at this point in time, is in the bag.

Moderately stocked farms (2-2.5 LU/ha), should be spreading approximately 23 N units/acre in the first application. As already established, this should be urea, and will thus equate to half a bag per acre.

Growth rate

The average growth rate across the country is beginning to pick up. The national average is just under 8kg DM/ha/day, with southern counties very near the 10kg DM/ha/day mark. Once again, with mild, relatively dry conditions coming this weekend, have a look around the shed and identify groups of stock for turnout. You might not get a better chance.

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Grass+: high temperatures to boost growth