Mechanical harvesting and cleaning of Calendula officinalis and Dimorphotheca pluvialis

From 1990 to 1994 the research institutes of the Agricultural Research Department in the Netherlands (DLO-NL) investigated potential new arable oilseed crops for industrial application as part of the National Oilseeds Programme (NOP). The Institute of Agricultural and Environmental Engineering (IMAG-DLO) studied the mechanical harvesting and cleaning of Crambe abyssinica, Dimorphotheca pluvialis, Calendula officinalis and Euphorbia lagascae. This paper describes the research conducted on the crops Calendula officinalis and Dimorphotheca pluvialis, using three harvesting methods: combining (New Holland 8070), combining after chemical desiccation and combining after windrowing. Gross yield, moisture content of harvested seeds and foliage, seed losses and impurities of the seeds were measured. It was found that both crops could best be harvested with a combine harvester after chemical desiccation. Timely harvest seemed to be important to avoid weather damage and excessive seed shedding. Calendula seeds were cleaned using an air-screen cleaner, Dimorphotheca seeds using an air-screen cleaner, a brushing machine and an indented cylinder separator.