Applying late nitrogen to maize by drone raised predicted fresh-weight yields by up to 10 tonnes a hectare in trials by agronomy company Hutchinsons near Broughton Astley in Leicestershire. Maize needs more than 30 percent of its nitrogen after tasselling, crop nutrition specialist Rob Jewers said, but by then crops are often too tall for conventional machinery, and dry soils limit uptake of granular nitrogen.

Foliar nitrogen helps in dry conditions, but high temperatures narrow sprayer windows because of scorch risk; a drone, agronomist Greg Hopkinson said, "offers greater flexibility". Three products were applied on 22 July: N-Durance, a methylated urea, at 20 litres/ha; Peloton, a foliar mix of phosphorus, potassium, magnesium and zinc; and Align-N, an 18 percent foliar urea.

Plot cuts showed about 10 t/ha more fresh weight where N-Durance and Peloton were combined, while Align-N gave no benefit. With drone application at £35/ha and a total cost of £115/ha, and maize valued at £40 a tonne, the team estimates a return of about £400/ha.

The drone, a DJI T50 operated by SAS Agri Drone Services, carries a 40-litre tank; the product volume of 100 litres/ha is the limiting factor, and trials of a 30 litres/ha product are under way. Hutchinsons is also testing drone-sowing cover crops into standing maize so they are established by harvest, worth £129/ha under the Sustainable Farming Incentive against about £75/ha for seed and sowing.

Photo: Marilyn Peddle / Wikimedia Commons (CC BY 2.0)

Source: Farmers Weekly