Establishment and Winter Survival of Carrot Grown for Seed in Central Oregon.

Carrot seed is produced in central Oregon by planting seed in late-summer, 13 months before harvest.  Seedling carrot growth and development is sometimes poor possibly because of nematodes, herbicide carryover, or allelopathy from wheat straw.  Frost-heaving is a risk factor that strongly influences winter survival of seedling carrot in the region.  Frost-heaving occurs when freezing and thawing soil pushes seedling carrots up out of the soil, which results in plant mortality.  Two field trials were conducted to evaluate the influence of wheat straw management on seedling carrot injury and the potential for herbicide carryover from wheat.  Two additional field trials were conducted to evaluate mulch products to prevent frost-heaving.  Wheat straw management practices influenced carrot establishment and seedling carrot survival over the winter.  Seedbed preparation strongly influenced carrot establishment and winter survival.  Biomass mulches were all equally effective in preventing frost-heaving.