The high organic matter (muck) soils in the Holland Marsh, Ontario, Canada, are prone to wind erosion, especially in the fall and winter months. Good canopy coverage of ideally 30%, is important for protecting the soil and reducing soil erosion. Carrots are usually harvested in October. Cool temperatures at this time result in slow germination and growth of cover crop species. Field trials were conducted to assess the efficacy of various cover crops and methods for rapid establishment after carrot harvest. One approach to increasing germination and emergence is seed priming. Seeds of barley, oats, and triticale were primed by soaking for 24 hr in water (hydro-priming) or potassium nitrate at 5 mg L-1 (osmo-priming). Seed was dried for 24 hours and then seeded into pots placed in controlled environments at 5, 10 or 21°C. Priming generally resulted in faster germination and higher biomass especially at lower temperatures of 5 and 10°C. Primed and non-primed seed was seeded into high organic matter soil (50% organic matter, pH 6.9) on 17 Oct. and crop growth was assessed on 13 Nov. There were no advantages of priming in the field trials. Non-primed barley had high or higher canopy coverage (13%), plant counts and dry weight, compared to other species and primed seed. Barely was also grown as transplants with 2 seeds/plug and transplanted in the trial on 17 Oct. This treatment had higher canopy coverage (25%) and dry weight than seeded treatments. However, using barley transplants is not a cost effective option at this time. In a separate trial on an adjacent site, barley was over-seeded into standing carrots on 27 Sept. at 200 kg ha-1, and the carrots were harvested on 17 Oct. Barley and fall rye were direct seeded on 17 Oct. Pre-harvest seeding of barley resulted in significantly better establishment, canopy coverage and biomass, although all were low, maximum 12% coverage. There was a strong positive correlation between canopy coverage and biomass production across all trials. More research is needed on cover crops species and establishment methods.
