Mr. Gil experimented with three cover crop mixtures and sequences to see how effective they were for weed suppression. These were 1) spring wheat, plowed down after first frost-free date and followed by Japanese millet and alfalfa, 2) rape, buckwheat, Dutch white clover, sorghum/sudangrass, and soya, and 3) oats, field peas, and hairy vetch. Each trial was planted on 1/3 acre.
He found that the alfalfa in trial #1 was smothered by the millet which, having gone to seed, proved a pest in subsequent years. Trial #3 was generally successful, though the vetch came up late, and therefore poorly, as it was crowded by the oats and peas. Trial #2 appeared the most successful.