The Effects of Deficit Irrigation and Different Potassium Levels on Seed and Oil Yield of Canola in Shahrekord Region

Water deficiency is one of the limiting factors in canola (Brassica napus L.) production in arid and semi-arid regions. Past researchers have shown that potassium increases plant resistance to water stress. This study was conducted to assess the simultaneous effects of water stress and application of different levels of potassium fertilizer on canola in the field of Agriculture and Natural Resources Research Center of Shahrekord. For this purpose, a split-plot experiment in randomized complete block design was carriedout with three replicates. The main plots were three levels of drought stress including: I1: irrigated with full level of water requirement during plant growth stages with 5690 m3/ha, I2: irrigated with 85% of water requirement in stemming, flowering and podding stages, and I3: irrigated with 70% of water requirement in flowering and podding stages. The sub plots were five levels of potassium fertilizers including K1=control, K2=0/75R, K3=1R, K4=1/25R and K5=1/5R (R=fertilizer recommendation based on soil testing). Means comparison were conducted with Duncan test at 5 percent level. Results show that irrigation treatments had significant effects on straw yield and total yield. Potassium treatments had significant effects on all characteristic except on pod length, grain oil percentage and potassium percentage in shoot. Potassium fertilizer application did not have any significant differences on some of growth indices but it slightly decreased the negative impacts of water deficiency. Thus, based on the results of this research, in deficit irrigation condition, the best treatment with high yield is I3K3 treatment.