Influence of Harvester and Weather Conditions on Field Loss and Milling Quality of Rough Rice

Abstract

<abstract> <bold>Abstract.</bold> A better understanding of factors affecting field losses and milling quality during harvest is needed to improve the economic value of rice. The main objective of this study was to evaluate the impact of harvester header, harvester type, and weather conditions on field loss and milling quality of rough rice. Four popular harvesters equipped with different headers: John Deere 9870 with header D60-S, John Deere 9860 with header D972-S, Hardy, and John Deere 9770 with striper header were used in this study. The header and total field losses of rice were evaluated for each harvester under regular, rainy and windy weather conditions. Tests were conducted in a rice field cultivated with medium grain rice, variety M206, at Grimes, CA. Total rice yield (TRY), head rice yield (HRY) and whiteness index (WI) were examined to evaluate the effect of weather conditions on milling quality. The obtained results revealed that the rice field loss was affected by harvester header and type, and weather conditions. The conventional header had rice loss less than that of the stripper header. Additionally, for conventional headers, D60-S significantly reduced the rice loss compared to the D972-S and the Hardy. Harvesting with John Deere (9860) resulted in significant header and field loss compared to other tested harvesters. The average loss increased from 236.2 and 445.2 kg/ha under regular condition to 711.1 and 907.9 kg/ha under windy condition for John Deere (9870) and John Deere (9860), respectively. The highest loss percentage reached to 10.1% under windy condition for John Deere (9860) due to lodging. HRY was significantly affected by weather condition at harvest time. However, the weather condition had no significant effect on TRY and WI. To minimize the rice field loss and obtain good milling quality, commercial rice harvesting during regular weather conditions is important. Also, the use of conventional harvester header could cause less field loss compared to the stripper header. A proper combination between harvester type and header could be vital for reducing the rice loss.