Study of Source and Different Levels of Potassium Fertilizer on Canola (Brassica napus L.) Production

Increasing the area of arable oilseed land, particularly rapeseed, and the important role of potassium in yield and oil content, especially in calcareous and high pH soils, need to more knowledge about plant nutrition requirement. In this study, the effect of sources and different levels of potassium fertilizers on some quality and quantity characteristics on canola yield were assessed by combined analysis factorial experiment based on randomized complete blocks design during 2011-2013. Two potassium fertilizer sources: potassium sulfate and potassium chloride with four levels of potassium fertilizer control, 100, 150, 200 kg.ha-1 in main plot and sub plot, respectively. Results of combined analysis of variance showed effect of potassium sources on capsule in plant and oil yield was significant at 5% probability level. Also effect of potassium rate on capsule in plant, seed yield and oil content was significant at 5% and 1% probability level. Interaction effect of treatments on capsule in plant, seed yield, oil yield and oil content was significant. Potassium chloride fertilizer impact on yield and its components showed better results. Interaction effects of sources and rates of potassium showed the highest seed and oil yield (2128 and 878 kg.ha-1, respectively) from 100 kg.ha-1 potassium chloride treatment. Also the highest capsule in plant and seed in capsule obtained from 150 kg.ha-1 potassium chloride treatment. Finally, for increasing canola yield application of 100 kg.ha-1 potassium chloride recommended.