PERFORMANCE EVALUATION OF FORMS OF UREA AND TIME OF APPLICATION ON YIELD AND YIELD TRAITS OF BREAD WHEAT ON VERTISOLS AND CAMBISOLS OF TIGRAY, ETHIOPIA

Abstract

A field experiment was carried out to evaluate four forms of urea and the time of application on yields of wheat in the 2017 cropping season on Vertisols and Cambisols of Ofla, Tigray. The treatments were arranged in a split-plot design. The main plot was time of application (at planting and split application), and the subplot was forms of urea (prilled urea, super granular urea, urea stabil and granular urea) at the recommended rate of 64 kg N ha^-1. Before planting, soil samples were collected and analyzed following the standard procedure. The soil analysis results revealed that organic carbon and total nitrogen content were low at both sites. Application of different urea forms and time of application were statistically significant on yields of wheat at both sites. In Vertisols, the highest grain (3576.3 kg/ha) and straw yield (4483 kg/ha) were harvested from plots receiving urea stabil. But in Cambisols, the highest grain (5103.1 kg/ha) and straw yield (5895.5 kg/ha) was obtained on plots treated with prilled urea (conventional urea). The lowest grain and straw yields were recorded on plots treated with super granular urea at both sites. Split application of urea was the better method than planting application at both sites. Urea stabil, prilled urea, and granular urea can be used as a nitrogen source of fertilizer for wheat production, but super granular urea is less efficient for cereals. Further study should be done on the solubility of urea forms and in improving nitrogen use efficiency on different crops.