Survey of the direct and interaction effects of nitrogen and sulphur on two cultivars of canola

Keeping in view which 90% of oil consumption imported from abroad, investigation on canola for increasing yield and quality improvement as well as self-sufficiency in oil production is necessary. Nitrogen and sulfur are the first and the fourth elements respectively which required for canola growth, therefore a three years field experiment conducted in the Zarghan agricultural research station. The present study was a split plot in randomized complete blocks design with three replications. Licord and Talayeh cultivars were the main factor and twelve combination of four levels of nitrogen (0,120,180 and 240 kg/ha) from urea and three levels of sulfur (0, 50,100 kg/ha) from golden bio-sulfur was used. Urea applied in three stages (1/3 in planting time, 1/3 in steaming and 1/3 in flowering initiation). Phosphorous, potassium and other micro nutrients based on soil testing before sowing time were used. Flowering initiation, end of flowering, duration of flowering period, bush height in harvesting time, number of pod in main steam, number of seed per pod, 1000 seeds weight, seed yield, oil percentage and canola oil seed yield were measured. Related data analyzed using F test and Duncan, s multiple range test. Due to some difficulties which happened in the first years, only three parameters (seeds yield, oil percentage and oil yield) were measured. However, in the second and third years besides above mentioned parameters, the others factors were measured. The first year results showed that fertilizers treatments were significant in 1% levels on seed yield while the effect of cultivars and the interaction between cultivars and fertilizers were not significant. However, analysis of variance showed that the effect of cultivars were significant in 5% levels while the fertilizers effect as well as the interaction between fertilizers and cultivars were significant on canola oil percentage in 1% levels. Although there were a significant difference between flowering initiation and end of flowering in two years but the effect of year on flowering duration period were not significant, while the effect of fertilizers effect on 5% levels and interaction between years and fertilizers in 1% levels were significant. Interaction of year and fertilizer treatments on oil yield in the 1386-87 to compare with 1385-86 showed that the former was more sensitive to nitrogen consumption. In different levels of nitrogen application there was no significant difference effect among sulfur consumption levels.