Nitrogen uptake and productivity of late-sown wheat (Triticum aestivum) as influenced by row spacing and weed management

A field experiment was conducted during winter (rabi) season of 1992-93 and 1993-94 to find out nitrogen uptake and productivity of late-sown wheat (Triticum aestivum L, emend. Fiori & Paol.) as influenced by row spacing and weed management. Higher values for crop biomass, effective tillers/m(2), grain and straw yields and N uptake by the crop were recorded with 18 cm row spacing, whereas 15 cm row spacing reduced the weed counts, weed dry biomass and N depletion by weeds as compared with 20 cm row spacing. Weed-control treatments recorded significantly higher yield attributes, grain and straw yields, protein content and N uptake by crop than weedy check. Among the weed-control treatments, higher values of these parameters were noticed with hand-weeding which were at par with other weed-control treatments expect mixture of lower dose of 2,4-D and isoproturon (0.2 kg/ha of each herbicide). Weed-control treatments significantly reduced the weed count, weed dry biomass and N depletion by weeds than weedy check. Among the treatments, minimum weed count, weed dry biomass, N depletion by weeds and higher weed-control efficiency were recorded under hand-weeded plot. Mixture of 2,4-D and isoproturon each @ 0.4 kg/ha was as effective as application of higher dose of each individual herbicide in controlling weeds and produced almost equal grain yield.