EFFECT OF NITROGEN FERTILIZER RATES AND SOME GROWTH REGULATORS TREATMENTS ON SUGAR BEET

Abstract

Two field experiments were carried out at El – Hamoul, Kafr El – Sheikh Governorate in 2009 / 2010 and 2010 / 2011 seasons to study the effect of four nitrogen fertilizer rates (0, 70, 90 and 110 kg N / fed) and five growth regulators treatments (sprayed plants with tap water (control), Mepiquate Chloride (pix) at the concentration of 1000 and 2000 ppm and Indole acetic acid (IAA) at the concentration of 100 and 200 ppm on yield of sugar beet. The experiments were laid out in split plot design. The obtained results showed clearly that average root / top ratio, sucrose %, potassium %, sodium %, top yield / fed, root yield / fed and sugar yield / fed were significantly affected by nitrogen fertilizer rates in both seasons. Increasing nitrogen fertilizer from 0 to 110 kg N / fed caused 102.14 and 103.53 %, 112.55 and 118.18 % as well as 136.70 and 142.60 % increases in top yield / fed, root yield / fed as well as sugar yield / fed compared to plants grown on the control treatment (no added nitrogen) in 2009 / 2010 and 2010 / 2011 seasons, respectively. Results recorded indicated that all studied traits were significantly affected by growth regulators treatments in both seasons. Sugar beet plants sprayed with IAA at the concentration of 200 ppm gave the highest top yield / fed 5.75 and 5.86 tons, root yield / fed 27.65 and 28.98 tons as well as sugar yield / fed 4.46 and 4.70 tons compared to other treatments in 2009 / 2010 and 2010 / 2011 seasons, respectively. The interaction effect between nitrogen fertilizer rates and growth regulators treatments was significant on all studied traits in both seasons, except sodium % in 2009 / 2010 seasons. Fertilizing sugar beet plants by nitrogen fertilizer at the rate of 110 kg N / fed and sprayed with IAA at the concentration of 200 ppm gave the highest top yield / fed 7.73 and 7.83 tons, root yield / fed 36.90 and 39.84 tons as well as sugar yield / fed 5.65 and 6.13 tons as compared to all other this interaction treatments in 2009 / 2010 and 2010 / 2011 seasons, respectively. Generally, it could be recommended that fertilized sugar beet plants with 110 kg N / fed and sprayed by IAA at the concentration of 200 ppm increased root and sugar yields/ fed at El-Hammoul, Kafer El-Sheikh Governorate conditions.