Optimization of Combine Harvesting, Threshing, and Separating Systems for Reducing Corn Loss

Harvesting corn with a combine harvester leads to a certain degree of loss and thus reduces profits; although this loss cannot be fully eliminated, it can be controlled to areasonable degree. Preparing the combine for harvesting corn is a process involving the replacement of the harvest head and the concave and also the placement of cover plates on the threshing drum. A major obstacle in harvesting corn is the prevention of grain loss, which mostly occurs during the harvesting process at the combine head (when separating corn cobs from the stalks) and at the threshing drum and the concave (because of the corncobs’ breaking). The present research was conducted in a 400 acres farm property of the Seed and Plant Improvement Institute, Maize and Forage Crops Research Department, with prerequisites being a threshing drum speed of 750rpm and a crop moisture content of 11.6% on dry basis. The crop yielded and the amount of grain loss measured indicated that, when conventional heads exerting vertical force for separating the stalks are used, the degree of grain loss during harvesting becomes excessive; these heads cause a great amount of crop loss. Results of the present study were manifested on the combine cutter bars; therefore, for reducing harvest loss occurring at the combine header, headers made in Iran should be significantly modified. The first step taken in this respect was to design and implement necessary modifications to the two main parts of the machine, i.e. the “corn head” and the “feeder unit”.

Corn Combine, Reducing Harvest Loss, Combine Header Modification, Threshing Drum and Concave, Feeder Unit