David Walsh-Kemmis grows malting barley for both brewing and distilling purposes on his Co. Laois tillage farm.
Courtesy of his presentation to the recent Teagasc malting barley webinar, he reviewed his fertiliser management priorities within both cropping scenarios.
“Most of the farm is either Index 2 or 3 for both potash and phosphate,” he explained.
“Cover crops have been grown for the past five years. And we will make a cut in the fertiliser nitrogen rate accordingly.”
Walsh-Kemmis continued:
“This year we have had really good cover crops. They were sown really early. The mild autumn that followed really helped their development.”
Teagasc has analysed the cover crops currently growing on the Walsh-Kemmis farm. It is estimated that they will contain approximately 45kg/ha of nitrogen.
“We will be working on the basis that 20% of this nitrogen will become available to the subsequent barley crop,” said Walsh-Kemmis.
“And, we will reduce the amount of chemical nitrogen applied to the barley on that basis.”
Walsh-Kemmis also plans to reduce the overall amounts of nitrogen applied to his barley crops this year. The figures are: 135kg/ha for brewing and 110kg/ha for distilling.
Where phosphate and potash are concerned, the plan is to take a steady-as-she-goes approach
“Given the price of fertiliser, it doesn’t make sense to try and build the levels of either plant nutrient,” said Walsh-Kemmis.
“It will be a case of adding phosphorous and potassium on the basis of envisaged crop offtakes at harvest.
“But because we have decent soil reserves already in place, I am pretty happy to push ahead with this plan. Hopefully the price of fertilisers will come back down again at some stage n the future.
“We are also doing a lot of straw chopping on the farm. Hopefully, this practice will add to the soil phosphorous and potassium levels over time.”
Meanwhile, Teagasc has carried out a series of trials over recent months to assess the actual nitrogen content of catch crops and the proportion of this nutrient that is made available to subsequent crops.
Significantly, this work has shown that adding 2,000 gallons per acre of slurry prior to drilling catch crops can almost double fresh weight yields and the amounts of nitrogen within these crops.
The crops grown were mustard and a combination of leafy turnip and forage rape.
The Teagasc work also confirms the benefits of an August sowing date versus one in September.
Applying slurry to later-sown catch crops is not recommended.