Evaluation of Cultural Weed Control Methods in Soybean (Glycine max) to Improve Crop Competitiveness
Effects of cultural weed control methods in soybean were examined under moderate and high weed populations for their effect on crop canopy closure and canopy closure. The reference treatment was a slender soybean cultivar planted at a standard seeding rate (400,000 seeds/ha) with no pre-plant nitrogen added. Field studies were conducted in Elora, Ontario and Woodstock, Ontario in 2014 and 2015. Treatments included two levels of each: pre-plant nitrogen, seeding rate, competitive cultivar selection, and weed pressure. Weed emergence, above ground weed biomass, canopy light transmittance, and soybean yield were measured. Weeds continued to emerge until canopy closure regardless of treatment; there was also little difference in canopy closure between treatments. Nitrogen treatment alone (P=0.0214) and in combination with the bushy soybean cultivar (P=<0.0001) were found to reduce above ground weed biomass. No one cultural control was consistent in improving soybean yield at either location in 2014 or 2015.