Phenology of Maize ( Zea mays L. ) and Associated Weeds as Influenced by Tillage and Weed Control Methods under Mid-Hill Conditions of North West Himalayas

A field study was conducted on silty clay loam soils to study the effect of tillage and weed control methods on phenology of maize and associated weeds and their influence on the production of crop. The results revealed that irrespective of tillage and weed control methods, Digitaria sanguinalis, Echinochloa colona and Panicum dichotomiflorum and sedge (Cyperus iria) emerged earlier by 4-8 days than maize crop resulting more competition in the initial stages of growth. Commelina benghalensis emerged and senescenced almost along with the crop. While all other weeds flowered at tasseling stage of the maize crop, Echinochloa colona and Panicum dichotomiflorum flowered 7-8 days earlier to this stage. Senescence of almost all the weeds except Commelina benghalensis occurred 15-25 days earlier than the maize crop. Zero tillage resulted in significantly early emergence of the crop by 4-5 days over other tillage methods but the emergence of grass weeds was not affected significantly. Appearance of all the phenophases of the crop and associated weeds was initiated early in zero till plots as compared to raised seed bed and conventional tilled plots resulting in reduction in grain yield of maize by 13.7 and 16.9 per cent over raised seed bed and conventional tillage. Effective control of weeds with atrazine 1.5 kg/ha and acetachlor 1.25 kg/ha delayed the emergence and appearance of different phenophases of weeds than the crop resulting in 75.2 and 71.7 percent average increase in grain yield of maize, respectively over unweeded check.