M.A. Thesis:

The effect of weed interfernce with cooton in conventional and ultra row spacing condition

To investigate the effect of weed interference duration on yield and yield components of of cotton (Gossypium hirsutum L.) in conventional and ultra row spacing condition, a field experiment was conducted at Sabzevar in 2014-2015. Experiment was conducted as factorial arrangement in a randomized complete block design with three replications. Experimental factors were conventional and ultra narrow row and duration of weed interference (0, 30, 40, 650 and 60 days after emergence. Row spacing in conventional and ultra narrow row was 20 and 70 cm, respectively. Analysis of variance showed that cultivation system had significant effect on plant height, number of branches, boll weight, seed cotton yield, biological yield and lint yield whereas boll number and Gin out-turn was not affected by cultivation system. Weed interference during statistically influenced all traits except Gin out-turn. cultivation system* weed duration had significant effect on plant height, boll number, seed cotton in boll and biological yield. Means comparison showed that ultra narrow row had 13.24% and 59.47 lower weed density and weed dry matter compared with conventional, respectively. In ultra narrow row system, Cotton had more plant height, seed cotton yield, lint yield, biological yield and seed yield and less number of branches, boll number and boll weight than conventional system. Increasing of interference duration was decreased plant height (18.31%), lateral branches (25.78%), boll number (37.04%), boll weight (44.86%), biological yield (44.25%) seed cotton yield(61.22%), lint yield (61.52%) and seed yield (60.80%). In conclusion, results showed in both conventional and ultra narrow row condition, weed interference reduces seed cotton yield that this reduction was more in conventional than ultra narrow row condition.

Keywords: Cotton; Competition, Ultra narrow row, interference, Weed