PRODUCTIVITY AND QUALITY OF SUGAR BEET AS INFLUENCED BY NITROGEN FERTILIZER AND SOME MICRONUTRIENTS

Abstract

Two field experiments were conducted during 2008/2009 and 2009/2010 seasons at Sakha Research Station, Kafr EL-Shaikh Governorate to study the influence of three nitrogen rates (75, 100 and 125%) of recommended rate (RR=80Kg N/fed), sprayed with Zn, Mn and Fe individually or in mixture, on some chemical composition, juice quality and yield of sugar beet plants. Decreasing N dressing up to 60 Kg N/fed (75% of RR) significantly decreased photosynthetic pigments (chlorophyll a, b and carotenoids) at the age of 120 days from sowing in the two seasons, also a reduction in sucrose% and some technological parameters such as sugar extractable (SEX), sugar losses to molasses (SLM) and sugar coefficient (Sco), yield component (root length, diameter and fresh weight of tops in the two seasons have been recorded. Yields of roots and sugar, uptake of N, Mn and Zn had the same trend. On the other hand, increasing N dressing up to 100 Kg N /fed (125% of RR) significantly increased photosynthetic pigments i.e. chlorophyll a,b and carotenoids at the age 120 days from sowing in the two seasons, Na, K and α- amino N as impurities, sugar loss to molasses (SLM), yields of roots and sugar but juice purity was significantly decreased. Foliar spray with Mn, Zn and Fe individually or in mixture significantly increased chlorophyll a, b and carotenoids in both samples in the two seasons. Sucrose% and impurities as K and αamino N were significantly increased but juice purity was significantly decreased. Root length, diameter, fresh weight of roots and tops, sugar yield were significantly affected. Foliar spray with Zn, Mn and Fe significantly increased their uptake and N uptake. Foliar spray with the mixture of Zn, Mn and Fe exhibited the best treatment, where it gave the highest values of most traits under study. The interaction between N at the high rate and the mixture of Zn, Mn and Fe was the superior treatment where, it gave the highest values for chl a, b and carotenoids, K, α- amino N, juice purity and N uptake.