Short-term green manure effects on crambe yield and oil content

Crambe (Crambe abyssinica Hochst. ex R.E. Fries) is an oilseed crop that can be cultivated in tropical conditions and used for the production of industrial oil. While crambe is believed to be a suitable crop for no-tillage systems, identification of appropriate crop species to precede it is necessary to improve its grain yield and oil content. In this study, we aimed to assess the short-term effects of crop rotation on the grain yield and oil content of a crambe crop cultivated after spring-summer cover crops. The experiment was conducted on an Rhodic Hapludox soil in Santa Helena-PR, Brazil. The experimental design consisted of randomized blocks with four replications. The plots consisted of pearl millet (Pennisetum glaucum), grass brachiaria (Brachiaria brizantha), sorghum (Sorghum bicolor), sunn hemp (Crotalaria juncea) and a fallow area (spontaneous vegetation). Grain yield, oil content, and oil yield were measured. Crambe oil content was influenced by the cover crops. The use of crotalaria as predecessor species resulted in higher oil content, but the result did not differ from that observed in the fallow area. However, grain yield and oil content were benefited by the crotalaria cover crop in the short-term. Crambe looks promising as an alternative oilseed crop for South Brazil when seeded in autumn with crotalaria cover crop in Rhodic Hapludox.