Performance Evaluation of Three Sugar Cane Varieties under Different Levels of Nitrogen Fertilization and Two Seeding Rates

Field trials including two plant cane crops and one 1^st ratoon were conducted in El-Mattana Agric. Res. Station, (latitude of 25.17° N and longitude of 32.33° E), Esna, Luxor Governorate, Egypt, during the two successive seasons of 2013/2014 and 2014/2015 to find out the performance of three sugar cane varieties (G.T. 54-9, G. 2003-47 and G.2003-49), which were planted using two planting densities (1.5 drills "37800 buds/fed" and 2 drills "50400 buds/fed") and fertilized with three nitrogen levels (180, 210 and 240 kg N/fed "fed = 0.42 ha-1"). A randomized complete block design (RCBD) using split-plot arrangement with three replications was used. The varieties were allocated in the main plots, mean while planting densities and nitrogen levels were randomly distributed in the sub–plot.
The important results could be summarized as follow:
Variety G.T.54-9 over passed the two promising varieties in length, diameter and fresh weight/plant of stalks. The two promising varieties (G.2003-47 and G.2003-49) over passed the commercial variety (G.T.54-9) in brix, purity and sugar recovery percentages and number of millable in the three crops. Variety G.2003-47 gave the highest sugar yield in the two crops and ratoon.
Planting density 37800 buds/fed attained a significant increase in stalk diametercompared with planting by 50400 buds/fed, meanwhile, the same planting density i.e. 37800 buds/fed produced the higher stalk fresh weight in the two plant cane crops and 1^st ratoon. Planting density 50400 buds/fed attained the highest taller stalks, brix, purity and sugar recovery percentages, number of millable cane/fed and cane and sugar yields/fed, meanwhile, the same density reduced glucose % in the different crops.
Increasing nitrogen levels up to 240 kg N/fed led to significantly increased in stalk length, stalk diameter, stalk fresh weight/plant, number of millable cane/fed, cane yield/fed and sugar yield/fed for the three cane crops. Increased nitrogen levels from 180 to 210 and 240 kg N/fed caused significant increase sugar yield/fed in the three cane crops, this increment amounted by 15.67 and 23.24 % in the 1^st planted cane, 13.83 and 18.81% in the 1^st ratoon and 6.45 and 8.10 % in the 2^nd planted cane, respectively.
The highest number of millable cane/fed was recorded when sugar cane planted with 50400 buds/fed and fertilized by 240 kg N/fed.
Variety G.T.54-9 attained the highest stalk fresh weight values with the different nitrogen levels over the two promising varieties. The best interaction was between variety G.2003-47 and 210 kg N/fed to produce the highest purity % in the three crops. The interaction between the varieties and nitrogen levels attained a significant influence on sugar recovery % in the 1^st ratoon and the 2^nd planted cane.
The 2^nd order interaction between varieties, seeding rates and nitrogen levels recorded the highest cane yield/fed, however, this difference was not enough to reach the level of significant in the three crops.
It could be noted that from the economical view of growers’ benefit planting the promising sugar cane variety G.2003-47 is better, however the actual and the economical view growing the commercial variety with higher costs is better for the national economy where it will save about 2.49 ton/fed which represent a large amount of cane on the large area consequently a large amount of sugar production.