Published online by Cambridge University Press: 20 January 2017
Recovery of common agricultural weeds after burial by soil was studied infour greenhouse and three field experiments. Species studied includedvelvetleaf, Powell amaranth, common lambsquarters, barnyardgrass, and giantfoxtail. Seedlings were bent over before burial to simulate the effect ofthe impact of soil thrown by a cultivator. Altogether, more than 35,000seedlings were marked and observed for recovery. No seedlings recovered from4 cm of burial. Recovery from complete burial under 2 cm of soil ranged from0 to 24% depending on the experiment, species, and watering treatment, butrecovery greater than 5% was rare. Large-seeded species tended to recoverfrom complete burial under 2 cm of soil better than small-seeded species.The study did not reveal a difference in recovery of grasses relative tobroadleaf weeds. Overall, seedlings tended to recover best when water wasapplied daily after burial, worst when water was applied once on the day ofburial, and to an intermediate extent when no water was applied. However,difference in recovery between the no-water and watering-once treatmentswere usually small. Also, many experiment by species combinations showed nosignificant differences among watering treatments. When even a small portionof the seedling was left exposed, recovery generally exceeded 50%. Organicweed management systems commonly use burial of weed seedlings with tineweeders and soil thrown by sweeps and hilling disks to control weeds in croprows. Recovery from burial could pose a substantial weed management problemin some circumstances, particularly for large-seeded weed species.Maximizing burial depth is important for limiting recovery. Recovery fromburial can be minimized by withholding irrigation for several days afterhilling-up operations.
Associate Editor for this paper: Martin M. Williams, III, USDA-ARS.