Abstract: Apparatus carried on a self-propelled vehicle field processes alfalfa to obtain therefrom fiber and protein components and a deproteinized liquid component which is simultaneously applied on the field as the vehicle advances. The apparatus includes a harvesting head assembly which is mounted on the front of the vehicle to cut the alfalfa and means to convey the alfalfa rearwardly to a macerator which shreds the harvested alfalfa. The macerated alfalfa is separated into fibrous and liquid fractions by a dewatering press which is connected to the macerator by a conveyor. The fibrous fraction is blown rearwardly into a trailer pulled behind the vehicle. The liquid fraction is heated to a predetermined temperature and is pumped into a holding tank wherein the protein in the liquid coagulates and floats on the deproteinized liquid. The protein is skimmed from the deproteinized liquid and is collected in a storage container mounted on the vehicle.