Explanation:

Aerial topdressing is the aerial application of fertilisers over farmland using agricultural aircraft. It was developed in New Zealand in the 1940s and rapidly adopted elsewhere in the 1950s.The first known aerial application of agricultural materials was by John Chaytor, who spread seed over a swamped valley floor in Wairoa, New Zealand, in 1906 using a hot air balloon with mobile tethers.The first known use of a heavier-than-air machine in aerial application was on 3 August 1921 when, as a result of advocacy by Dr Coad, a USAAC Curtiss JN4 Jenny piloted by John A. Macready was used to spread lead arsenate to kill catalpa sphinx caterpillars near Troy, Ohio, United States. The first commercial operations were attempted in the US in 1924 and use of insecticide and fungicide for crop dusting slowly spread in the Americas and, to a lesser extent, other nations.