When to spread slurry and where to spread it are two key questions that will be addressed as part of the grassland management part of the Teagasc Beef Open day tomorrow.
Stan Lalor, Research Officer with Teagasc will be looking at these two questions on the day. With slurry worth over €20 per 1,000 gallons, he says it is important that farmers make the most of its value. Speaking recently, he said we put a lot of focus on slurry from a nitrogen application point of view. However most of the value of that slurry is in Potassium (P) and Phosphorus (K).
He says that farmers need to be targeting parts of the farm that are low in P and K or that have high P and K requirements. Usually these will be the fields that have the lowest P and K soil types and are being cut for silage in a grassland situation, he said.
For Lalor, the key point with slurry is that most of the value is P and K. “When to spread is when you have decided where it will go,” he says.
“It is about putting it out when it gets best value for the nitrogen. The key issue here is in relation to ammonia volatilisation, which increases in hot and dry weather. That is why generally we would recommend spring, as opposed to summer, application as a result.”
When spreading a key factor is the weather on the day of application. “A man said to me once:’ the best way to explain the optimum conditions for spreading slurry is to say Spread on a day when the farmer is wearing a t-shirt and the wiper of the tractor is on intermittent.’”
“He is wearing a t-shirt which means it is warm and there is a bit of growth. The wiper of the tractor is on intermittent which means the day is cloudy, overcast and a bit misty. This means there is reduced ammonia volatilisation.”