Aerial topdressing is the aerial application of fertilizers over farmland using agricultural aircraft. It was developed in New Zealand in the 1940s and rapidly adopted elsewhere in the 1950s. Although this is quite common in areas where they do crop dusting and fertilizing, most people never see this.
Aerowork is a company in New Zealand that provides this service and the video below shows how they do this, making many runs per day. I found it amazing that they use the uphill part of the runway to slow down and the opposite to "launch" themselves back into the air. This aircraft was applying "lime" to the crops.
The aircraft is a Pacific Aerospace, Model: Cresco 08-600 The PAC Cresco is a turboprop-powered derivative of the FU-24 PAC Fletcher aerial topdressing aircraft, manufactured by the Pacific Aerospace Corporation in Hamilton, New Zealand.