The objective of this paper was to evaluate the influence of phosphorus fertilization on the interference relationship between maize and purple nutsedge plants. An experiment was set up in 90L pots filled up with a mix of sand, soil and commercial substrate PlantMax®. The experimental treatments were combinations of pot colonization by maize and/or purple nutsedge; initial density of purple nutsedge tubers (25 or 50 tubers/pot) and three doses of phosphorus fertilization (increase of soil phosphorus level in 0, 100 and 300 ppm). The interference relationships between the two species were affected by phosphorus fertilization. The maize plants showed excellent response to phosphorus fertilization and improved its interference in purple nutsedge plants and drastically reduced the weed response to phosphorus soil amendment. Maize interference reduced the number and dry matter accumulation of purple nutsedge shoots and tubers. Under the maize interference, purple nutsedge showed higher resources partitioning to tubers than to shoots. Purple nutsedge interference reduced maize plant height, dry matter accumulation in leaves and stems and leaf area expansion.
competition; Zea mays; Cyperus rotundus; weed density
