The effect
of nitrogen and potassium fertilizers on growth parameters and carbohydrate
contents of sweet sorghum cultivars
Abass Almodares*1, Reza Taheri1,
III Min Chung2 and Majid Fathi1
1Department of Biology, Isfahan University,
Isfahan - 81846-73441,Iran
2Department of Crop Science, Konkuk University,
Seoul - 011-470-8310, Korea
(Received:
January 25, 2007; Revised received: August 05, 2007; Re-revised received:
September 01, 2007; Accepted: October, 2007)
Abstract: Sweet sorghum is tolerant to high
temperature and drought and can be considered as an alternative crop to sugar
beet and maize in Iran.
In this study, the effects of nitrogen and potassium fertilizers on growth
parameters including stem height, stem diameter, stem fresh weight, total fresh
weight; carbohydrate contents including total sugar, brix
value, sucrose content and purity; and juice extract of two sweet sorghum
cultivars were determined. Three rates of N-fertilizer (0, 90, 180 kg urea ha-1)
and two rates of K fertilizer (0 and 50 kg potassium sulfate ha-1)
assigned as main plots and two sweet sorghum cultivars (Rio and Keller) as
subplots. Growth parameters at soft dough and physiological maturity stages and
carbohydrate contents at physiological maturity stage were determined. Results
showed that application of 180 kg urea ha-1 as compared to control
at physiological maturity significantly (p<0.01) increased stem height
(12.65%), stem fresh weight (24.57%), total fresh weight (78.22%), total sugar
(39.25%), sucrose content (9%) and juice extract (34.96%). Application of 50 kg
potassium sulfate ha-1 increased (p<0.05) stem fresh weight
(24.33%), total fresh weight (25.44%), total sugar (10.50%), and juice extract
(9%) at physiological maturity. The highest growth parameters, carbohydrate
contents and juice extract were obtained with the application of 180 kg urea ha-1
and 50 kg potassium sulfate ha-1 using cultivar (cv) Keller. The best results were taken with the
application of both fertilizers.
Key
words: N fertilizer, K
fertilizer, Sweet sorghum, Growth parameters, Carbohydrate contents
PDF of full length paper is available with author (*almodares@sci.ui.ac.ir, aalmodares@yahoo.com)
Copyright ? 2008 Triveni Enterprises. All rights reserved. No part of the Journal can be reproduced in any
form without prior permission. Responsibility regarding the authenticity
of the data, and the acceptability of the conclusions enforced or derived, rest
completely with the author(s).