Abstract:
Study was carried out to determine optimum time of withholding irrigation period before
harvesting of sugarcane at Omo Kuraz Sugar Development Project, Ethiopia.
Experiments on two varieties, N Co 334 and B 52 298 planted in adjacent fields
characterized with clay soil during 2014. The experiment was designated with two
sugarcane varieties (N Co 334 and B 52 298) and five withholding irrigation periods
(WIPs) treatments for 20, 30, 40 50 and 60 days and the treatment was laid out in
randomized complete block design (RCBD) with four replications. The data on soil
moisture content, cane height, cane weight, cane diameter, number of internodes, number
of millable canes, moisture percent cane, fiber percent, cane yield, cane yield per month,
top to bottom ratio brix in cane juice, Brix %, Pol %, purity, reducing sugars, estimated
recoverable sugar, estimated sugar yield, and estimated sugar yield per month were
analyzed using SAS package. Error variances for most characters were found to be
homogeneous and the data were subjected for analysis of variance. The soil moisture
percent differed at five different WIPs with lowest at WIP for 60 days. Variation in soil
moisture was caused by occurrence of rain during WIPs for 30, 40 and 50 days. Cane
height, cane weight and number of internodes per stalk increased significantly at the
subsequent WIPs with maximum at 50 to 60 days. Millable canes in plots at the five
WIPs were on par. Moisture and fibre percent in cane decreased and increased
significantly at subsequent WIPs, respectively. Quality characters, top to bottom ratio of
Brix in juice, Brix, pol or sucrose and purity percent in composite juice, and sugar
recovery percent cane differed at five WIPs. Above quality characters increased
significantly at subsequence WIPs being highest at WIPs for 50 and 60 days. Reducing
sugars percent juice declined significantly with increase in days for WIPs with lowest at
WIP for 60 days. Cane yield and cane yield per month were on par at WIPs. Estimated
sugar yield and sugar yield per month tons per hectare increased significantly at
subsequent WIPs with maximum at WIP for 50 and 60 days. The results revealed that
optimum period for withholding irrigation was 50 to 60 days for obtaining maximum Pol
or sucrose in cane. Therefore, it was suggestive that irrigation to sugarcane should be
withheld for at least 50 to 60 days for enhancing sugar accumulation in cane before
harvesting in the month of May under the conditions of South Omo Kuraz Sugar
Development Project.
