Seed quality and efficiency of mechanical harvest of castor crop at commercial scale

Mechanization of the harvest is the main challenge for increasing the production of castor in the world ( Ricinus communis ). This study evaluated the header JLS Kascavel, which was designed specifically for harvesting castor, with fingers that vibrate and rotate to remove castor fruits, and a threshing unit adapted as the grain elevator. In this harvesting equipment, the castor plant is not cropped, and only the fruits enter in the combine harvester to be cleaned. The device was tested for two years (2023 and 2024) under operation in the harvest of castor field at commercial scale. The highest seed loss occurred in the header (152 – 216 kg/ha), while there was low rate of not-harvested fruits (6 – 26 kg/ha). The cleaning shoe was very effective, the seed loss was negligible in this step of the process, and it did not vary along the day. The harvest efficiency was 88.8 % in 2023 and 83.5 % in 2024. The harvested product had from 91.9 % to 92.2 % (by weight) of normal seeds (excluding broken and empty seeds, fruit husk, and other impurities). Along the day, the rate of broken seeds was the lowest around noon. The resistance to break of castor fruit peduncle was strongly associated with the relative air humidity. • Equipment for castor seed mechanical harvest is described and evaluated. • The header JLS Kascavel picks only fruits without cutting the whole plant. • Most of seed loss occurred in the header. • Seed loss from the cleaning shoe was very low. • Seed quality varied along the day and was the highest at noon.