A harvesting machine for threshing crop materials includes a platform supported in front of a chassis, an erecting device having a number pairs of guiding bars attached to the platform and having a channel formed between two bar members of each pair of guiding bars, a guiding element disposed between every two adjacent pairs of guiding bars for guiding a stalk of the crop materials into the channel of the guiding bars, a number of pawls extended into the channel for sending the stalk of the crop materials into the channel, and a cutting device having two or more cutting elements for cutting the stalk into a lower base segment that carries no grain and an upper straw segment that carries grains.
