Impact of crop density and soil fertilization on sugar beet

ABSTRACT:Sugar beet is an important industrial cropand the second highest source of sugar providing after sugar cane. Around 30% of the total annual sugar production in the world is from sugar beets. In order to evaluate the effect of plant density and nitrogen fertilization on sugar beets, two field experimentswere conducted in a randomized complete block design with four replications in two different locations of Iran including Experimental Research fields in Agriculture and Natural Resources center, Mashhad, and agricultural research farm of sugar factory in Torbat-Jam,2011.Studiedfactors consistedthree crop densities (60,000, 90,000, and 120,000 plants per hectare), three nitrogen fertilizer levels (0%, 50%, and 100% requirement to nitrogen) and Twolevels of biological fertilizers (Application ofNitroxinand without applicationbiological fertilizer). Nitroxin is biologicfertilizer with Azosprolium bacteria and Nitrobacteria. Generallythis study showed increment plant density from 60000 to 120000 plants per hectare generally decreased the impurities sodium and potassium in root pulp in both Torbat-jam and Mashhad locations.Also, utilizing bio-fertilizer; 50% reduction of nitrogen (100 kg nitrogen per hectare); and the density of 90,000 per hectare,had the desired quality of sugar beets with the minimum impurities (sodium, potassium, and alpha-amino nitrogen), and the maximum of pure and impure sugar yield and extractable sugar amountwereobtained. By increasing nitrogen application up to 200 kg per hectare,the percentages of extractable sugar and pure sugar in root pulpwereincreased.As a conclusion, biological fertilizer application in sugar beet could increase qualitative characteristics of sugar beets root and reduced consumption of chemical nitrogen fertilizer in both locations.