The effects of rate and timing of N application on sugar beet crop

Sugar beet root in some regions  of  Esfahan province have undesirable quality. Such low qualities are reported to be due to irrigation with nonsaline water. On the other hand, in these regions, the high application rate and timing of N fertilizer is considered to be responsible for the low quality of sugar beet root. The objective of this research was to evaluate the impacts of  nitrogen application rate and timing on the yield and quality of sugar beet root. This study was conducted in Kabotarabad Research Station. The soil had a silty clay loam lexture. The main plots were fertilized with 90,135, 180 and 225 kg  N/ha respectively. The subplots were treated as 1) 100% N applied after thinning, 2)50% N before planting, and 50% after thinning, 30 25% N before planting 50% N after thinning and 25% N one month later and 4)25% N before planting 25% N after thinning and 25% N one month later and 25% N two months later. The amount of N had no significant effect on the root yield, however the sugar content, sodium, potassium, a-amino nitrogen, purity and sugar molasses were affected considerably. An increase in the amount of N increased sugar molasses. The timing of N application had no effect on the not significant. Consequently, in regards to economic production of sugar beet, in regions with no salinity limitations, it is recommended to apply 90 kg/ha net nitrogen entirely after thinning. If 20% of starter N is supplied by fertilizer sources such as ammonium phosphate or urea.