EFFECT OF LEAF DEFOLIATION, BORON AND NITROGEN FERTILIZATION ON YIELD AND QUALITY OF SUGAR BEET

Abstract

Two field experiments were conducted during 2005/ 2006. and 2006/ 2007 seasons at the Experimental Farm of Faculty of Agriculture, Saba Bacha, Alex. University, to investigate the effect of nitrogen and boron fertilization levels as well as leaf defoliation on yield and quality of sugar beet. The experiment with three replicates in a split -spli,t plot design was applied where the main plots were used for the nitrogen treatments (30, 60, 90 and 120 Kg N /feddan as ammonium nitrate 30.5 %) the subplot for the boron treatments . Data announced in Tables (11),(42)and(43) interpreted the effect of defoliation rates on loss sugar percentage during the two growing seasons of 2005/2006 and 2006/2007. Data declared that loss sugar percentage was no significant difference was found between defoliation rates of O'X, 25% and 50 % in both seasons.

(0,0 0.5, and 1.0 Kg B I feddan ) as borax (Sodium borate Na2 B2 02 10 H2 0) 11 o;;) Band the sub- sub plots for the leaf defoliation were done 30 day, before harvesting with three levels ( 0.0%, 25'Yo and 50% of total leaves ancestrally 0, 6 and 12 leaves ) were removed to represent the last percentage mentioned before in respect to that the average total leaves per plant was 24 leaves . All treatments were distributed randomly

Characters studied in the present investigation were : number of green leaves, fresh weight of leaves /plant (gm), dry weight of leaves /plant (gm), L.A.I., CGR, S.L.A, root weight (Kg) I plant, root diameter (em), root length (em), root yield (t/fed), fresh top yield (t/fed), biological yield (t/fed), sugar yield (t/fed), T.S.S., sucrose %, purity %, extractable white sugar %, soluble non sugar contents, loss sugar % alkalinity coefficient (AC) and a-amino nitrogen%.

The obtained results could be summarized as follows 5-1- Effect of nitrogen levels on growth parameters of sugar beet plants:- 5- 1-1. Leaves characters: 5- 1-1-1. Number of leaves I plant: Nitrogen fertilizer levels significantly affected the number of leaves /plant. The number of leaves I plant increased with increasing nitrogen levels. The number of leaves decreased at 200 days than the previous growth period (170days) with increasing nitrogen fertilizer levels at the first and the second seasons, respectively. 5-1-1-2. Fresh weight of leaves (gm) /plant : The values of fresh weight of leaves per plant significantly increased as nitrogen fertilizer levels increased from 30 kg up to 120 kg N/fed at the 140 days from plantation .The highest values (719 gm/plant) was recorded by applying 120 kg .N/fed rate in the first season and (1156 gm /plant) in the second season.. 5- 1-1-3. dry weight of leaves (gm) /plant Dry weight of leaves significantly increased as nitrogen •fertilizers level increased up to 120 kg N/fed at growth period during the two seasons of this study.