Tow and Fert: Slurry cuts fert application

Driving down fertiliser use through applying it in a foliar slurry has shown good results for an Irish farm  and was highlighted at a recent field day.

Metalform’s liquid fertiliser mixer and applicator wagons, Tow and Fert machines have been sold into the Irish market for the past five years and sales and marketing manager Tim Henman says the company has supplied more than 70 units, with another batch due to leave the Dannevirke yard before Christmas.

The O’Connor family of Kanturk, County Cork, milk  390 cows  at 3.22 livestock units/ha,  feeding 750kg meal per cow and producing 400kg milksolids (MS)/cow. The family have managed to drive fertiliser usage down from 36.45 tonnes (T) of urea in 2020 to 18.36T in 2022 and 18.28T in 2023 (a total of 100kg N/ha) which Tim says was applied over 7-10 rotations of the grazing platform and supplied enough N for two cuts of silage. Silage  yielded 5.75T DM/ha for the first cut with two separate foliar applications supplying all N,P,K and S requirements. The second cut yielded 4.3t DM/ha with slurry applied followed by one foliar application three weeks later.

The Irish farmers, as with their Kiwi counterparts, are realising the efficiency and flexibility of applying the fertiliser when it suits them and in smaller doses – fitting in around the weather.

Henman says the Irish farmers have also picked up on NZ research from 2011 that highlighted the significantly increased nitrogen response efficiency  (measured in kg DM produced per kg N applied) of urea applied in fine particle form with Agrotain urease inhibitor  over the granular form.

Pastures grew 23kg DM/kg of applied N when applied in fine particle form with the inhibitor, and N leaching was hugely reduced to 0.04% of applied N lost, when compared with 10kg DM grown per kg of applied granular N, of which 2.1% of applied N was leached during the three rainfall events during the 63
day trial.

The research shows up to 47% less N can be applied for the same drymatter response, Henman says.

The machines are very flexible for application of a range of products in one pass, all dissolved in water, and plant available without relying on rainfall, and without risking a big rainfall event potentially flushing the nutrient through the soil profile.

“The mix can include urea, humates, trace elements, herbicide, potash or mono- ammonium phosphate, lime flour among others – and the Tow and Fert Mix Calculator App on the farmers phone can do all the calculations of how much to add to the hopper and how much water and how fast to drive to get the required application rate – so no tricky maths required,” Henman added.

The machine really extends the window of fertiliser application because the nutrient is suspended in water, farmers can still apply their nitrogen without the need for a rain event, which would be valuable if the predicted El Nino  dry event kicks in this summer, Henman said.