Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 15, 2004
Publication Date: February 1, 2004
Citation: Anderson, R.L. 2004. Response of no-till winter wheat to plant density. Proceedings, Colorado Conservation Tillage Association 2004 High Plains No-Till Conference. February 3-4, 2004. Greeley, CO. pp. 1-9. Interpretive Summary: Producers are changing their production practices because of no-till. A no-till system leads to more water in the soil, thus crop yield potential is greater. Producers are asking if seeding rates for no-till winter wheat should be increased to improve grain yields. We determined in a series of studies that winter wheat yield is highest at seeding rates of 65 to 90 lbs/acre. In addition, producers will gain ancillary benefits with these seeding rates because more crop residues will remain after harvest. For example, corn yields are higher in high residue systems whereas weed densities are lower. But, we also noted that if seeding rates are too high, winter wheat may consume too much water during vegetative growth and have more leaf diseases during years of above-normal precipitation. Consequently, yields will be reduced in these conditions.
Technical Abstract: Because no-till has increased the amount of soil water available, producers are asking if seeding rates for winter wheat should be increased to improve grain yields. The conventional seeding rate has been 45 lbs/ac. With no-till, seeding rate studies indicate that increasing the seeding rate to 65 or 90 lbs/ac will increase yield 3 to 8%. Producers will gain ancillary benefits with higher seeding rates, as more crop residues remain after harvest. The higher residue levels increase yield of corn the following year by reducing soil water evaporation. Also, the higher residue levels reduce the number of weed seedlings that establish in summer annual crops. However, producers may weaken their production systems if seeding rates are too high (greater than 90 lbs/ac). With higher seeding rates, winter wheat may consume too much water during vegetative growth, and also favor leaf diseases during years of above-normal precipitation with the dense canopy. In these situations, grain yield may be reduced.