Effect of Combined Application of Different Micronutrients on Productivity and Quality of Sugar Beet Plants (Beta vulgaris L.)

The experiments were conducted throughout two successive winter seasons 2010/2011 and 2011/2012 at Belquas, Dakahlia Governorate, Egypt. The aim of this work was to investigate the effect of foliar application with different micronutrients with excluding one element each treatment and its addition times on the productivity and quality of sugar beet plants. The treatments were six combinations of micronutrients, T0 (spraying with water),T1 (Fe+Zn+Mn+B), T2 (T1-Fe), T3 (T1-Zn), T4 (T1-Mn), T5 (T1-B) and two application times (once after 60 days from sowing or twice after 60 and 90 days from sowing) at 50ppm for each in the form of (Zinc sulphate, Manganese sulphate and Boric acid) and 100ppm in the form of Iron sulphate. Results indicated that, T1 recorded the highest values for yield characters i.e. root, top and sugar yields as well as root weight and dimensions as compared with other treatments followed by T2. Moreover, the results concluded that T1 treatment produced the maximum sucrose %, purity %, recoverable sugar % and white sugar yield followed by T2 in both seasons, this proving that Fe was the least effective microelement on productivity and quality traits of sugar beet. On the other hand, T3 and T4 recorded the lowest values of all yield and yield components and this may be due to the role of Zn and Mn in plant growth as well as their effect as metal components of some enzymes. Furthermore, Zn and B followed by Mn positively affected the impurities content i.e. K, Na and amino N % as well as sucrose loss to molasses, so the absence of Zn or B have more impact on sugar beet quality. The obtained results showed that foliar application with micronutrients twice (60 and 90 days) after sowing significantly increased root, top and recoverable sugar yield and improved sucrose % and purity % in both seasons. Generally, it could be concluded that spraying micronutrients mixture twice (Fe+Zn+Mn+B) produce the highest productivity and quality of sugar beet under the environmental conditions of Dakahlia Governorate.