STUDY ON THE INFLUENCE OF MOISTURE CONTENT AND COMPRESSION RESISTANCE CHARACTERISTICS OF CORN GRAIN ON THRESHED BREAKAGE RATE

Abstract

High breakage rate is the bottleneck that restricts corn grain mechanical harvesting in double-cropping area in China. The moisture content and compression resistance characteristics of corn grain have important effects on the breakage rate at threshing. In this paper, 5 corn varieties planted in double cropping area were selected and the effects of grain moisture content and compression resistance characteristics on threshed breakage rate were studied. Results showed that both the grains moisture content and the compression resistance characteristics had effects on the threshed breakage rate. The lower the moisture content, the greater the force required for breakage, and the more difficult it was to break. Meanwhile the breakage rate was also related to the displacement during pressing. The smaller the displacement, the lower the breakage rate, but if the displacement was too small, the corn was a silty variety and the breakage rate was still high. When the moisture content was 33%±1%, the threshing verification test showed that the average breakage rate of DH605, LY296 and KN21 was 5.39%, 5.02% and 7.13%, respectively, which was not suitable for grain mechanical harvesting under high moisture content (moisture content higher than 30%). However, the average breakage rate of LK868 and LD6018 was 4.76% and 4.25% respectively, which was suitable for grain mechanical harvesting under high moisture content. This research could provide a reference for corn varieties selection suitable for mechanical kernel harvesting in double cropping area.