Population Dynamics of Weed Flora and their Growth in Tall and Dwarf Wheats as Influenced by Sub-optimal Levels of Irrigation and Nitrogen

An experiment was conducted to study the population dynamics of weeds and their competition intall and semi-dwarfwheatunder sub-optimal levels of irrigation and nitrogen. M. indica, C. album and A. ludoviciana were major weeds. Irrigation treatments did not affect weed densities when recorded at 60 DAS. Three irrigations, however, caused 18.9 and 5.1% increase in growth of grass and broad leaf weeds, respectively, at 120 DAS over one irrigation. Though the two genotypes did not alter weed, densities and weed growth, the seed production of dominant weed, A. ludoviciana was significantly reduced when grown in association with tall semi-dwarf C 306 as compared to Kundan. Application of N favoured population build up and growth of A. ludoviciana and suppressed density and growth ofM. indica. Application of 40 and 80 kg N ha⁻¹ led to enhanced growth of wild oats by 184 and 276% over no N treatment. Corresponding increase in seed production of wild oats per m¹ was 263 and 408%.