Comparison of methods and timing of seedbed preparation in early seeding of sugar beet (Beta vulgaris L.)

To investigate the effect of different tillage systems in early seeding of sugar beet, a field experiment was conducted under two climatic conditions: Karaj, Motthari field station, in three years (2012-2013, 2013-2014 and 2014-2015) and Mian-do-Ab, Iran in two years (2012-2013 and 2013-2014). Nine seedbed preparation methods were examined including: two methods for fully preparing the seedbed in the fall (without and along with barley seeding), three methods for dormant seeding (along with barley seeding, without barley seeding and without barley seeding along with creating furrows after thinning in spring), two methods of preparing of seed bed in two season: fall and spring (without and using combined tillage), a minimum plowing method and a method for fully preparing of seed bed in the spring using randomized complete block design. Soil texture and organic matter content were also determined in each treatment in advance. The results showed that regarding to climate change, the dormant seeding in Karaj and Mian-do-ab would be at high risk. In Karaj conditions, one of the treatments of the seedbed preparation in two stages, including: deep Moldboard plowing in fall combined tillage in the spring, due to its desirable quantitative and quality characteristics of root during three years of experiment (in average 66 and 12 t.ha-1 root and sugar yield, respectively), was dtermined as a superior treatment. Where the planting is done on falt seedbed , other deep moldboard plowing, disc, leveler and chisel plow in the autumn disk in the spring (in average 67 and 11 t.ha-1 root and sugar yield, respectively) can be used. In Mian-do-Ab conditions, seedbed preparation in autumn including; deep moldboard plowing, disk, leveler and disk in autumn (in average 9 and 57 t.ha-1 root and sugar yield, respectively) was identified as superior treatment. Using this method, in addition to the possibility of optimal seedbed preparation, it would be possible to practice early seeding.