Studies on the Economical Properties of Combines (1)

On the Adequate Utilizing Time of a Combine for Rice

Abstract

A series of field experiments was performed intermittently in October to clarify the change of performance of a Japanese small combine (width of cutterbar 0.69m) in relation to progress of ripeness of rice plant. Results obtained may be summarized as follows:
1. As ripeness of rice plant progresses, the percentage of field loss of grain increases. Especially after the time of full ripeness, increasing tendency of field loss becomes remarkable. (Fig. 1)
2. As to items of field loss, the percentage of threshing loss is more than that of head loss, in the early stage of ripening but the latter becomes superior to the former in proportion to the progress of ripening. (Tab. 4).
3. From a viewpoint to minimumize field loss in the utilization of a combine, the adequate harvesting time of rice plant may be a period from later stage of yellow ripeness to the beginning of dead, which is later and shorter than the conventional harvesting time by a hand sickle.