Tuesday, November 6, 2007
152-4
Rolling Increases Broadleaf Weed Emergence.
In the northern Great Plains, annual forage and pulse crops typically are land rolled after planting to push rocks back into the soil to prevent damage to harvest equipment. A field trial was conducted to determine if land rolling, analogous to using a large packer wheel to improve soil-seed contact for more uniform crop emergence and subsequent maturity, influenced density or biomass of weeds associated with field pea, forage barley or summer fallow. The experiment included two planting dates each of two years for barley and pea. Preplant tillage was done with a field cultivator for all treatments. Crops were not treated with any herbicide. Across years, crops, and planting dates, land rolling approximately doubled early season emergence and densities at harvest of tumble mustard, Russian thistle, kochia, and redroot pigweed. Rolling resulted in a doubling of total weed biomass at harvest. Wild oat densities were not influenced by rolling. Rolling decreased pea yield by 300 kg ha-1, but did not influence soil water or water use. Land rolling can be used to decrease the broadleaf weed seed bank in an annual forage crop, but may increase problematic broadleaf weeds in pea.
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