Consider the Drone Crop Duster

It has a 20 foot flat wing on top, big chord, it is a slow flyer and carries 200 pound payload under the main wing.

But, 150 pounds of fee pellets dropped off to the south forty is now a breeze, just fill the hopper and press the green button. The ten cows out there are fed their supplemental, a 15 minute task.  At ten pounds an acre, i will seed, or fertilize  ten acres, with attachment in one flight. Take it to the field, treat it like a tractor. Total weight under wing less than 600 pounds, including wheels.  It is a tiny airborne tractor. Typical useable payload, 150 pounds. But with easy fill and empty, it can take continuous landings and takeoffs on the field, with smooth dirt.

Fully loaded the plane is 500 pounds,m still almost easy enough for  to push like a wheel barrow. The biggest weight is motor,  attachment, payload, fuel tank, the two major carbon fiber parts, wing and chassis. The drone is designed to break apart on crashing, saving the large components from damage. It is low speed, 80 -120 Mph.