How much is sole-cropping systems sustainable for camellia and crambe?

Crambe (Crambe abyssinica R.E. Fries) and camelina (Camelina sativa L. Crantz) are two oilseed crops belonging to the Brassicaceae family. Typically crops belonging to this family highly suffer from solecropping system, as extensively reported for oilseed rape (Brassica napus L. var. oleifera). Otherwise crambe and camelina are considered resilient species as demonstrated in the framework of the COSMOS (G.A. 635405) project, while in the MAGIC project (G.A. 727698) they have been identified also as suitable to grow in marginal land. But for a stable introduction of these two new oilseeds into typical European crop rotation schemes a full understanding of the effects of sole-cropping have never been carried out before. At this scope a multi-location and multi-year trial has been established in Italy (Bologna, 44°33’N, 11°23’E) and Greece (Aliartos, 8°22’N, 23°6’E) in 2017 and it is still ongoing, comparing the effect of sole-cropping vs. wheat-oilseed succession on one commercial variety of camelina (Midas, Linnaeus Plant Science, Canada) and on one of crambe (Galactica, Wageningen University and Research, The Netherlands). Since establishment in spring 2017, each year the oilseed is sown either on the past year stand or in a new stand in which winter wheat was grown the season before. The experimental design is a randomized complete block with 4 replicates. From the analysis of the first 2-year data surveyed at Bologna an interesting “species x cropping system” interaction effect emerged for seed yield, with camelina significantly suffering from mono-succession (-17%) while in crambe an increase on yield was surveyed (+10%). For all the other analyzed seed quality parameters (i.e., seed weight, oil and protein contents, fatty acid composition) negligible effects due to cropping system were surveyed in both species. The inclusion of the data obtained in Greece together with a further year of trials (2019) will permit to more clearly quantify the effect of solecropping systems in these two emerging oilseed crops, with outstanding potential for the European biobased industry. From these preliminary results crambe seemed more suitable to sole-cropping system than camelina