Response of some sugar beet varieties to methanol and method of nitrogen fertilizer application

Two experiments were conducted in 2003/2004 and 2004/2005 winter seasons to investigate the response of some sugarbeet varieties to nitrogen fertilizer applications alone or combined with methanol and their interactions. Three levels of methanol [zero (tap water), 15 and 30%] as foliar application. Nitrogen fertilizer was soil and foliar application as follows : Control (70 kg/fed. top dressing as solid urea), 70, 90 and 110 kg N/fed. (2/3 of each as soil application and 1/3 as foliar application) with 6% urea. The tested sugarbeet varieties were Del 939, Kawamira and Oscar poly. A split plot design, with three replications was used in both seasons. Where, sugarbeet varieties were arranged in the main plots, nitrogen fertilizer applications combined with methanol as foliar application occupied the sub-plots. The results showed that increasing nitrogen fertilizer applications combined with methanol as foliar application up to 110 kg N/fed. plus 30% methanol increased photosynthetic pigments (chlorophyll a, b and carotenoids in mg/g f.w.), soluble carbohydrates (reducing and non-reducing sugars in g/l00 g d.w.), purity % extractable sugar % yields of roots. Tops and sugars as well as sucrose content. On the other hand, impurities percentage (Na, K and alpha-amino N) were decreased. It is worth to mention that, nitrogen fertilizer applications combined with methanol had a positive effect on all studied traits except for sodium concentration in beetroots. Kawamira variety surpassed the other varieties (Del 939 and Oscar poly) in the content of chlorophyll (a), non-reducing sugars %, purity %, extractable sugar %, yields of roots, tops and sugar (ton/fed.) and sucrose content. In addition Kawamira variety contained lower impurities (Na, K and alpha-amino N). For the interaction between nitrogen fertilizers applications combined with methanol as foliar application and sugarbeet varieties, it was insignifican t for all studied traits, except for sugar lost to molasses, extractable sugar and top.