Response of Weed parameters, phenology and growth attributes of Maize to Plant Density and Weeding Frequency at Assosa District, Benishangul Gumuz Regional State, Ethiopia

Maize (Zea mays L.) is staple food crop grown in Benishangul Gumuz regional state of Ethiopia. However, its productivity is constrained by a number of problems out of which weed management and plant density is the most important ones. The experiment was conducted to determine effects of plant densities and weeding frequency on weed Control and productivity of maize in 2016 main cropping season at Assosa district, Ethiopia. Four levels of weeding frequency (no, one, two and completely weed free) and four plant densities [31250 plants ha^-1 (80 cm x 40 cm and one seed per hole), 44444 plants ha^-1(75 cm x 30 cm), 53333 plants ha^-1(75cm x 25cm) and 62500 plants ha^-1(80 cm x 40 cm and two seeds per hole)] laid out in a randomized complete block design with factorial arrangement in three replications.Main effects of weeding frequency and plant densities significantly (P<0.05) affected most of the measured phenological and growth parameters of maize. The dominant weed flora infesting maize field during growing season were Cyperusrotundus, Guizotia scabra, Eleusine indica and Hyparrhenia hirta. Higher leaf area (5628 cm²) and leaf area index (2.68), were achieved in twice hand weeded fields. significantly higher plant height (224cm) was obtained from completely weed free plots.   Higher plant height (224 cm) and leaf area index (3.2) were obtained from the highest plant density of 62500 plants ha^-1. There was also significant interaction effect of weeding frequency and plant density on weed density, weed dry matter and weed control efficiency. The higher weed density (221) and weed dry matter (741 g m^-2) were obtained at weedy check and lower populated (31250) plants ha^-1 of maize.  Thus, practicing of twice hand weeding and a plant density of 53333 plants ha^-1 (75cm x 25 cm) was found to be better to variety BH-546 production in Assosa area.