Several factors lay behind the development of aerial topdressing in New Zealand. A research flight helped develop Aerial Topdressing. But for topdressing something larger and more robust was needed. The fuselage was an all new design optimized for the topdressing role. The specific spreading of fertilizer is also known as "aerial topdressing "in some countries. The first experimental topdressing in Australia was done by a private Tiger Moth in 1948. Hopper load on topdressing would have varied between 12 and 17 cwt. In 1951 he began aerial topdressing his farm with a war-surplus Tiger Moth. In 1946 the first pure topdressing flight was conducted without seed. Aerial topdressing is the aerial application of fertilisers over farmland using agricultural aircraft. The Fletcher FU-24 aerial topdressing plane was loosely based on the FD-25 Defender. Large-scale topdressing started on 14 March 1949 spreading clover-super mix. To minimise impact, topdressing is now prohibited within certain distances of water.