Effect of Drainage Rate in Different Growth Stages of Canola as a Second Crop in Paddy Fields (Case Study: Guilan Province)



¬¬¬One of the most important limitations for selection of second crop in paddy fields in Guilan is waterlogging in the second half of the year. For an evaluation of waterlogging effect (in adequate drainage) on canola yield, a lysimeter study was conducted implementing -10,-5,0 and +5 cm water level for 2,5,7 and 10 day durations at 3 plant growing stages namely: emergence, beginning of flowering and 50% flowering stage in a factorial randomized block design. The variety of canola was Hyola 308.The results showed, increasing waterlogging duration would result in a substantially different lower yield, yield components and other traits except 1000-weight. Increasing waterlogging duration from 2 to 10 days resulted in 19.2% and 8.04% yield reduction and lower oil content, respectively. In addition, for every extra day of waterlogging from 2 to 10 days yield and oil content were lowered by 0.9 g and 0.44%. Yield and 1000-weight were substantially higher as a result of lowering the imposed water level from +5 to -10 cm. Yield and oil content increased by 11.7g and 7.4% when water level was lowered to -10 cm or 0.23 g and 0.15% for every cm of lower water level. Yield, number of sheath, dry matter and harvesting index show no sensitivity to stage of waterlogging. But number of seeds per sheath and oil content were sensitive to waterlogging during the third stage; namely: 50% flowering. One thousand weight was sensitive to waterlogging at the emergence stage.