Castor Bean Mechanical Harvesting: Crop Termination and Comparison Between Cereal and Sunflower Headers' Performance Installed on a Conventional Combine Harvester

Among the species currently cultivated for industrial vegetable oil production, castor bean (Ricinus communis, L.) could be a good candidate for future investments due to the good resistance to pests, tolerance to drought, and suitability for marginal lands cultivation. However, the mechanization is still not properly developed and high seed loss is experienced during the harvesting mainly due to the impact of the header on the plants. In the present study, the suitability of conventional combine harvester equipped with sunflower and cereal header was investigated by testing performance, seed loss from impact (ISL) and cleaning systems (CSL), and related cost. The effective seed quantity harvested by using both sunflower and cereal header was 92% w/w and 86% w/w of potential seed yield, respectively. This significant difference is due to the lower ISL associated with sunflower header which relies on different cutting system. On the other hand, the use of different headers did not affect significantly the cleaning of the seeds which averaged at 20% of the total seeds collected in both cases. In conclusion, the study highlights that a conventional combine harvester equipped with a sunflower performs well and the sunflower header could be the starting point for developing ad-hoc header specifically designed for castor beans harvesting.