Response of Bread Wheat (Triticum aestivum l.) Varieties to Nitrogen Fertilizer Application Rates at Wolaita Sodo, Southern Ethiopia

Abstract

Wheat is an important cereal crop in Ethiopia which is widely cultivated in different agro-ecologies. It is the main staple food for about 36% of the Ethiopian population. However, its production is constrained by a number of factors including nitrogen fertilizer. Nitrogen recommendations for major wheat producing areas based on soil type is scanty. Hence, in this content field experiment was carried out during 2015 main cropping season at Wolaita Sodo Agricultural Technical Vocational Education and Training College (ATVET) with objective of determining optimum N rate for wheat varieties. Treatments consisted in three wheat varieties (Hidase, Danada’a and Kakaba) and seven nitrogen fertilizer rates (0, 23, 46, 69, 92,115, and 138 N kg/ha) were combined in factorial and laid out in a randomized complete block design (RCBD) with three replications. Phenolgical, growth, yield components and yield responded differently to varieties, N fertilizer rates and their interactions.  Variety Danda a’ took the longest days to heading and physiological maturity whereas Kakaba took the shortest days to heading and physiological maturity. Increasing N fertilizer rates prolonged both days to heading and physiological maturity where the longest days to heading and physiological maturity were recorded at N rate of 138 kg/ha while both parameters were shortened at N rate of 0 kg/ha. Variety Kakaba had the highest plant height whereas Hidase showed the shortest plant height. On the other hand, the greatest spike length was recorded for Danda’a and least was seen for Hidase. The highest N rate resulted in the tallest plant heights and longest spike length. Regarding yield, the highest biomass was recorded for variety ‘Danda’a’ and lowest for variety Hidase. Biomass yield was increased with increasing N fertilizer rates where the highest biomass yield was recorded from N rate of 138 kg/ha and lowest from non N application plots. Significant differences were detected due to effect of variety by N fertilizer interaction on grain yield with highest grain yield  was recorded for Danada a’ at N rate of 138 kg/ha and lowest the lowest grain yield for Hidase at N rate of 0 kg/ha. Based on this finding it could be concluded that variety Danada’a  at N rate of  138 kg/ha is the optimum to be adopted for wheat production around experimental area and similar agro-ecologies.

Keywords: Nitrogen, Varieties, Economic feasibility, N use efficiency