Beet sugar industry in the tropics and subtropics is growing as an important component of sugar production. In Egypt, sugar beet has acquired more importance and becoming an important source of refined sugar. Large amounts of beet sugar byproducts are produced resulting in environmental pollution.
The surface application of molasses has significantly increased root yield, and the highest root yields were produced from either the control treatment and the application of 150 L/fed. of molasses to the soil surface. The highest root yield values were produced from the Belino variety under the control treatment and the Kawimera variety under the surface application of 150 L/ fed. of molasses. Surface application of molasses at the rate of 150 L/ fed. resulted in the highest sugar content. The highest values of the quality index, recoverable sugar (RS%) and recoverable sugar yield (RSY) from the Belino and Kawimera varieties were produced from the surface application of 150 L/ fed. of molasses. Meanwhile, the foliar application of vinasses at the rate of 4% (v/v) resulted in the lowest values of quality index, recoverable sugar% and recoverable sugar yield. The lowest values of Na%, K% and α-amino N% from both varieties resulted from the surface application of 150 L molasses. Moreover, the highest values of the quality index (QZ), recoverable sugar (RS%) and recoverable sugar yield were produced from the surface application of 150 L/ fed. of molasses. Compared to the control treatment, applying molasses at the rate of 150 L/ fed. improved the available N, P and K as well as the organic matter, calcium and magnesium contents in the soil after sugar beet harvest. The data indicate that molasses is a promising organic soil amendment that enhances sugar beet yield and yield-related traits through improving the physical and chemical properties of the soil. Besides, the application of beet sugar molasses can improve sugar beet quality through improving juice quality by reducing impurities content that retard sugar extraction.