RESPONSE OF THREE SUGAR BEET VARIETIES TO PLANTING DENSITY AND POTASSIUM FERTILIZER LEVELS UNDER SANDY SOIL CONDITIONS

Two field experiments were carried out at El-Khattara experimental farm, Faculty of Agriculture, Zagazig University, Sharkia Governorate, Egypt during the two successive seasons of 2011/2012 and 2012/2013. This study aimed to investigate the response of yield and quality of three multigerm sugar beet varieties (Rass Poly, Panther and Pleno) to three planting densities (28000, 33600 and 42000 plants/fad.) and three potassium fertilizer levels (0, 24 and 48 Kg K₂O/fad.) in sandy soil under drip irrigation system. The combined analysis results showed that Pleno variety surpassed the other two investigated varieties in root length and diameter, fresh root weight/plant, root and recoverable sugar yields/fad. In addition, its roots contained lower percentages of Na and K. Planting density affected on all traits, where increasing plant density up to 42000 plants/fad., significantly decreased root length and diameter, fresh top and root weights/plant, Na, K, alpha amino-N percentages and sugar loss to molasses (%). On the other side, sucrose (%), purity (%), extractable sugar (%), top, root and recoverable sugar yields were significantly and gradually increased. Moreover, root length, sucrose, Na, K, α-amino-N, extractable sugar percentages, sugar loss to molasses (%) (SLM) top, root and recoverable sugar yields were significantly increased by adding 24 kg K₂O/fad., while root diameter and fresh root weight/plant were significantly responded up to 48 kg K₂O/fad. The interaction between the studied factors revealed that the maximum root and recoverable sugar yields/fad., could be obtained by planting Pleno variety with the dense planting of 42000 plants/ fad., and applying 24 kg K₂O/fad.