Performance and Production of Brassicas Cover Crops in North Dakota.

Brassicas cover crops planted in the fall can recycle nutrients from the previous crop, provide soil protection, or be used as supplementary forage for livestock. This study was conducted to determine the performance and production of different brassica cover crop species in North Dakota. Seventeen brassicas species/cultivars were evaluated including turnip (Brassica rapa L.), forage rape (Brassica napus L.), radish (Raphanus sativus L.), Ethiopian cabbage (Brassica carinata A. Braun.), and hybrids. The experiment was conducted in 2013 in Prosper and Fargo, ND.  The experimental design was a randomized complete block with three replicates.  Seeding dates were 8 and 9 May and harvest dates were 21 and 15 November in Fargo and Prosper, respectively.  At harvest, fresh material (leaves + stem/roots) were collected, separated, weighed, and then dried.  Greatest total yield (leaves + roots) for turnip cultivars was 1.8 and 5.1 Mg ha^-1 for ‘Appin’ and 1.7 and 5.0 Mg ha^-1 for ‘Pointer’ in Fargo and Prosper, respectively. The hybrid Vivant had a leaf yield of 1.8 Mg ha^-1 and the radish ‘Groundhog’ had a root yield of 0.3 Mg ha^-1 in Fargo. In Prosper, ‘Appin’ had a leaf yield of 4.2 Mg ha^-1 and the radish ’Groundhog’ had a root yield of 1.5 Mg ha^-1. Brassicas cover crops had good performance during late summer and fall season, with high total yield (leaves + root) in a short growing season. The leaf biomass production was the most important component of the yield in all different species and locations.