Effects of Plant Density and Nitrogen and Bio fertilizer on Qualitative Characteristics of Sugar beet in Mashhad and Torbat-e-jam Regions of Iran

Plant density and Fertilizers application especially with biological fertilizers that reduces environmental and underground water pollutions, are very important in sugar beet production in the world and Iran. In order to evaluate the effect of plant density and nitrogen and bio fertilizers on qualitative traits of sugar beet (Beta vulgaris L.), two field experiments were carried out in Agriculture and Natural Resources Research Center in Khorasan-E- Razavi province in Mashhad, and agricultural research farm in Torbat-jam sugar factory during 2012. Experimental factors were consisted of three crop densities (60000, 90000 and 120000 plants per hectare), three amounts of N fertilizers (0, 100 and 200 kgN ha-1) and bio-fertilizers consist of Azosperillum and Nitrobacter, (with and without bio fertilizer). Experiments were laid out on the factorial design based on a completely randomized block designs with four replications. Results showed that the impurities of potassium and sodium in sugar beet root decreased with increasing plant density from 60000 to 120000 plants per hectare. Consumption of 200 kgN ha-1decreased gross sugar percent in sugar beet root. Bio-fertilizer and density of 90,000 plants per hectare with consuming 50% of N based on recommendations of soil test (100 kg ha-1), impurities of sugar beet root (sodium, potassium and α-amino nitrogen) decreased and white sugar yield and gross sugar yield increased. Therefore, using bio-fertilizers in sugar beet cultivation enhanced qualitative yield and caused lower application of chemical nitrogen fertilizer.