Manure Spreaders must be filled with (Solid) Manure in order to work. The entire device is mounted on wheels, with an attachment point that can be hooked to a towing vehicle.

The floor of the hopper has a conveyer belt that can push the Manure towards the back, where it is pressed into rotating corkscrews that will eject it out to the field. Each is comprised of a large open-topped box (a 'hopper') which can be filled with Manure. There are three Manure Spreaders available in the base game, and they are all functionally similar. Any patch of field covered with this material will yield double the normal amount of fruit, when harvested. The fertilizer material itself is a mix of straw and cow feces which is highly nutritious for plants. Manure Spreaders are machines that can be filled up with Manure, and then taken to a field where they will distribute it onto the soil. Read the individual articles to learn the actual recommended tractors for each Spreader.

The Power Requirements are suggestions only.

I was able to sell the starting Kramer tractors (i kept one for sentimental reasons), the cultivator, and the sower, keeping equipment to a minimum. seems to be pretty efficient while using a bunch of relatively cheap equipment. I basically just use this tractor, plus the starting harvester, and another SAME Argon3 hauling the starting tipper. The HORSCH cultivates as it seeds, and the Amazone ZZ-X fertilizes out the ass end as i'm seeding. I've gone a tiny bit further and hooked up the Amazone ZZ-X 1402 spreader to the back of the starting SAME Argon3 75 tractor, and put the HORSCH Express 3-point seed drill on the front of it.

This is all mentioned above, but it jives with my experimenting as well. at least one of the spreaders (i have Amazone ZA-X 1402) can be front or rear mounted (super handy) sprayers / spreaders take different sources, but refill at the same spot (slurry is elsewhere right?) water / fertilizer both give yield bonus, seems to be the same bonus So just to sum up for everyone who gets to the bottom of the thread:

Farming simulator 14 manure spreader