The impact of nitrogen fertilization, bio-fertilizers and molasses on the growth and morphological characteristics of sugar beet plants (Beta vulgaris L.)

Two field experiments were carried out at the research farm of Nubaryia Sugar and Refining Company (NSRC), located at (30°63' 88.93" N latitude; 30°22′ 46.21′′ E longitude), El-Behaira Governorate during the two successive fall seasons of 2019/2020 and 2020/2021. The main objectives of this study were to determine the impact of four nitrogen fertilizer levels (without, 60, 80 and 100 kg fed -1 ), three bio-fertilizers treatments (without, Cerealine® and T.S®), four Molasses levels (without, 20, 40 and 60 kg.fed -1 ) and their interactions on growth and morphological characteristics of sugar beet plants. A split-split plot design with three replications was used, where the nitrogen fertilizer levels were allocated in the main plots and bio-fertilizer treatments were distributed in the sub-plots, as well as molasses treatments occupied the sub-sub plots. The results indicated that increasing nitrogen fertilizer rates significantly improved growth, and morphological characteristics as well as the biomass of sugar beet plants. The high rates of nitrogen (100 and 80 kg N fed -1 ), bio-fertilizers treatments (T.S®) and molasses (60 and 40 kg N ‎ fed -1 ‎) alone produced the highest morphological characteristics (leaf area index, root length, root diameter), growth character (root fresh weight, leaves fresh weight and total fresh weight) throughout the 1st and 2nd seasons, respectively, without significant differences. The interaction between nitrogen rates, molasses and bio-fertilizers (80 kg N fed -1 + 40 kg Molasses fed -1 + T.S) gave the highest values for most all studied characteristics. So, bio-fertilizer treatments proved a major role in crop production optimization and are expected to reduce the pollution of the agricultural environment.