Response of rain-fed lowland rice varieties to different sources of N fertilizer in Fogera Plain, Northwest Ethiopia.

A field experiment was conducted for 2 years during the main cropping seasons of 2017 and 2018 in Fogera Plain to study the productivity response of lowland rice varieties to different sources of nitrogen fertilizer. The experiment was conducted using a factorial arrangement of three sources of N fertilizer (conventional urea, slow-release urea and urea supergranule) and three varieties of rain-fed lowland rice (Hiber, Ediget and X-jigna) laid out in a randomized complete block design (RCBD) with three replications. The recommended rate of 69 kg N ha^–1 was used for all three sources of nitrogen fertilizer. Results showed that highest soil-plant analysis development value, leaf area index (LAI), thousand-grain weight, biomass and grain yields of rice were recorded with the interaction of urea supergranule N fertilizer application and Hiber rice variety, while the lowest values of the parameters were recorded with the interaction of conventional urea application and X-jigna rice variety. Rain-fed lowland rice grain yield of 4.6 ton ha^–1 was obtained from the interaction of urea supergranule and Hiber rice variety. Economic evaluation results showed also that the highest net return of 58,947.50 Ethiopian Birr ha^–1 was estimated from the combination of urea supergranule and Hiber rice variety. According to the present results, the interactions of urea supergranule N fertilizer with Hiber and Ediget rice varieties were found as the first and the second outsmarted combinations that would be used further for exploiting more grain yield and net benefits of rain-fed lowland rice without yield penalty in Fogera Plain, northwest Ethiopia. [ABSTRACT FROM AUTHOR]