摘要：Two important rice varieties, Karacadağ Karakilçik (dark) and Karacadağ Beyaz (white) rice varieties are grown in the upper Mesopotamia region in Southeastern Turkey. Although the physical and mechanical characteristics of these rice varieties are different from each other, they are harvested using the same combine-harvester and thresher. Thus, high kernel losses and energy consumption occur during the harvesting stage. The rice stem cutting and kernel cracking properties have to be known for each variety for reducing grain losses and energy consumption. The exact knowledge of rice stem cutting energy and kernel cracking energy are the main parameters for optimizing design of cutting elements in harvesting, threshing, sorting, transporting and milling machines.The purpose of this study was to compare the relationships between rice stem cutting properties and kernel cracking force under load position for two local rice varieties of Karacadağ Karakilçik and Karacadağ Beyaz.The experiments in this study were conducted at stem moisture contents of 70.81 %, 41.60 % and 7.5 w.b, and kernel moisture contents of 24.10 %, 19.30 % and 8.7 % w.b. The cutting energy of stems were examined at three internode positions as lower (IN1), medium (IN2) and higher (IN3) mm down from the panicles for Karacadağ Karakilçik and Karacadağ Beyaz rice varieties. The stem cutting and kernel cracking forces were measured via Llyood Universal Testing Machine.The results indicate that the energy requirement of Karacadağ Karakilçik variety is greater than that of the Karacadağ Beyaz variety. Differences with regard to the cracking force and energy were determined between the horizontal and vertical sides. The cracking force of rice at horizontal orientation was determined to be higher than the cracking force at vertical orientation.
