Effect of conservational tillage and plant density on two cottons cultivars yield

In order to investigate the effects of different tillage systems, plant density and cultivar on yield of cotton, an experiment was carried out as a split - split plot in a randomized complete block design (RCBD) with 3 replications in Cotton Research Station of Hashemabad. Gorgan, Iran. The three tillage systems namely; 1) shallow tillage system (disk harrow), 2) reduced tillage system (cyclo tiller disk harrow) and 3) conventional tillage system (moldboard disk harrow) were assigned to main plots. The two cotton cultivars namely; Golestan and Khordad were considered as sub plot and three plant densities including 12.5, 6.3 and 4.2 plant per m2 were attributed to sub-sub plots. The results showed that tillage systems were no significant effect on yield of cotton. The lowest and the highest values of cotton yield were attributed to conventional and reduced tillage system, respectively. The two systems of reduced and shallow tillage systems yielded the lowest number of sympodia, length of monopodia and plant height; and the highest number of boll and 10 boll weights that caused an increase yield. With decreasing the plant distance from 30 to 10 cm, the number of boll and 10 boll weights were decreased, but the yield was increased with increasing in number of plant in a hectare. The highest value of yield cotton was attributed to Golestan cultivar at the reduced tillage plots and S1, with plant space of 10 cm.