Competition between Potatoes (Solarium tuberosum) and Weeds

Abstract

Mixtures of annual weeds emerging 1 week after and competing all season with potatoes (Solanum tuberosumL.) reduced tuber yields by an average of 54% compared to 16% in comparable treatments in which weeds emerged 3 weeks after potatoes. Weeds reduced tuber yields 19% 8 weeks after potatoes emerged and 25 to 45% 10 weeks after emergence. After full-season competition, for each additional 10% of the total dry biomass represented by weeds, there was a decrease of 12% in fresh tuber yield. This relationship was not valid if potatoes were harvested early, which reduced the deleterious effect of weeds on potato yields. Weed competition reduced both size and number of tubers, but had little effect on specific gravity of tubers. In some instances, the reduction in tuber size by weeds reduced the percentage of tubers that were marketable.