Ethiopian Journal of Science and Technology

Yield and yield component responses of sorghum (Sorghum bicolor (L.) Moench) varieties to nitrogen application in West Armachiho and West Belesa, North Western Ethiopia

Getachew Asmare, Alemayehu Assefa, Zenebe Gebremedhin — Tue, 08 Sep 2026 00:00:00 +0000

Sorghum is the most important cereal crop grown in Ethiopia. However, the average productivity in the study areas is very low. A field experiment was conducted in West Armachiho and West Belesa, during the 2023 main cropping season to evaluate the effect of nitrogen rates and sorghum varieties on crop productivity. Treatments consisted of a factorial arrangement of four levels of nitrogen fertilizer rates (0, 46, 92, and 138 kg N ha-1) and three sorghum varieties (Melkam, Girana-1, and local). The experiment was laid out in a randomized complete block design with three replications. The collected data were analyzed using R Software (R Package, Version 4.5), and significant treatment means were compared using the LSD test. Significant effects of nitrogen rates and varieties were observed on sorghum yield and related parameters. Most yield-related parameters showed the highest value at combination of Melkam variety and 138 kg N ha⁻¹ application. The interaction effect of N-rates and varieties was significant (p=6.22×10⁻⁴) on grain yield. The highest grain yield (5.3 t ha⁻¹) was recorded from 138 kg N ha⁻¹ applied to the Melkam variety. The maximum net benefit (USD 2,901.8) with a 365.3% Marginal Rate of Return (MRR) was obtained from 138 kg N ha⁻¹ applied to the Melkam variety. Therefore, based on the agronomic performance and partial budget analysis results, 138 kg N ha⁻¹ with the Melkam variety increased sorghum yield, while integrated soil fertility management, including crop residue retention, is recommended for fertility-depleted soils in West Belesa, West Armachiho, and similar agroecologies.

Determination of optimum rate and application time of nitrogen for yield and quality of malt barley (Hordeum vulgare L.) in Dabat district, Western Amhara, Ethiopia

Yeshambel Adugna, Zenebe Gebremedhin, Alemayehu Assefa — Tue, 08 Sep 2026 00:00:00 +0000

Malt barley is an important crop for Ethiopia’s agro-industrial development and smallholder livelihoods. However, its productivity and grain quality remain low due to suboptimal agronomic practices. To address this limitation, a field experiment was conducted to investigate the effects of nitrogen (N) application rates and split-application strategies on agronomic traits, yield, and grain quality. The experiment was arranged in a randomized complete block design with three replications, and data were analyzed using R statistical software (version 4.3.2). The treatments comprised 12 combinations: four N rates (46, 92,138, and 184 kg N ha⁻¹) and three application schedules (½ at planting + ½ at tillering; ¼ at planting + ¼ at tillering + ½ at booting; and ⅓ at planting + ⅓ at tillering + ⅓ at booting). The results showed that both N rate and application timing significantly affected spike length, kernels per spike, thousand-kernel weight, grain yield, and protein content. The highest grain yield (2.65 t ha⁻¹), thousand-kernel weight (43.04 g), spike length (7.97 cm), kernels per spike (42), and protein content (13.6%) were achieved at 184 kg N ha⁻¹. However, partial budget analysis indicated that the treatment with 92 kg N ha⁻¹ provided the highest net benefit (1324.84 USD ha⁻¹) and a marginal rate of return of 292.64%. Therefore, applying 92 kg N ha⁻¹ split as 1/2 at planting, and ½ at tillering stage is the most effective and economically feasible practice for malt barley production in the study area and similar agro-ecological zones.

Feeding habits and relative condition factor of Nile tilapia Oreochromis niloticus (Linnaeus, 1758) (Pisces: Cichlidae) in Damte Reservoir, Southern Ethiopia

Ermias Shirko, Elias Dadebo, Teshome Belay — Tue, 08 Sep 2026 00:00:00 +0000

The aim of the present study was to assess the feeding habits and relative condition factor of the Nile tilapia (Oreochromis niloticus (Linnaeus, 1758) in Damte Reservoir. A total of 584 O. niloticus samples were collected from two locations of the Reservoir based on their ecological differences. To diversify the sampling size, O. niloticus samples were additionally randomly selected from the fishermen's landings during four months of the dry season (February to May) and four months of the wet season (June to September). The collected data were summarized using descriptive statistics and analyzed with Microsoft Excel 2010 and SPSS v27 software. The diet compositions were expressed based on frequency of occurrences and volumetric contributions. From the total fish samples, 371 (63.53%) contained food in their stomachs, while 213 (36.47%) stomachs were empty. Detritus, macrophytes, and phytoplankton were the most frequently occurred food categories with relatively high volumetric contributions in the stomachs of fish. Notable changes were observed in the contributions of detritus, macrophytes, and phytoplankton, where their volumetric contributions increased with fish size. The major food categories remained consistent between seasons, though their volumetric contributions varied. The mean combined relative condition factor (Kn) value was 1.14 ± 0.014 for mixed sexes of O. niloticus. From the results of the present study, O. niloticus is an omnivore feeding on a wide range of food categories in Damte Reservoir. Female O. niloticus had higher mean Kn values than males, but the difference was not statistically significant (p > 0.05). Based on this finding, it is recommended to conduct further detailed studies to keep the overall conditioning of O. niloticus from the Reservoir.

Enhancing sesame seed yield through participatory identification and promotion of high-performing irrigated varieties for Northwestern Ethiopia

Tue, 08 Sep 2026 00:00:00 +0000

In Ethiopia, irrigation-based sesame production is constrained by multiple factors, with the limited availability of improved varieties being a major bottleneck. This study aimed to evaluate the seed yield performance of improved sesame varieties through farmers’ participation. Participatory variety selection followed by demonstration and pre-scaling up of selected varieties was conducted in Metema district during 2019 and 2022-2024 under irrigation, respectively. Seventeen varieties, including a local check, were evaluated to select the best-performing varieties. A mother-baby trial approach with an RCBD design with three replications was used. Agronomic data were collected from the mother trial, while farmers’ varietal and trait preferences were gathered from the baby trial. The demonstration and pre-scaling-up were conducted on farmers’ fields to assess further and identify varieties, and to create demand through promotion. Analysis of variance (ANOVA) was performed in R software and revealed significant differences (p<0.05) among the tested sesame varieties for all traits except branch number. The results revealed significant variation among the evaluated sesame varieties, with the highest seed yield recorded for Ado (2,084 kg ha⁻¹), followed by Adi (1,891.5 kg ha⁻¹). These two varieties also produced the highest number of capsules per plant, while thousand-seed weight ranged from 2.2 g in the local check to 3.7 g in Adi. Based on farmers’ preference assessment, which considered traits such as number of capsules per plant, uniform maturity, plant height, seed color, and overall field performance, Adi was highly preferred due to its superior yield performance, attractive whitish seed color, and market desirability. Consequently, Adi was demonstrated and promoted under farmers’ conditions, which generated considerable interest and demand for its seed. During the pre-scaling phase, Adi produced a mean seed yield of 1,330 kg ha⁻¹ under farmers’ management conditions. Considering its stable performance, preferred seed color, and strong farmer acceptance, Adi was recommended for wider promotion and commercial production under irrigated conditions, while Ado, despite its higher yield potential, requires further evaluation and scaling-up efforts to enhance its adoption.

Agronomic, yield and yield component responses of lowland rice (Oryza sativa L.) variety (Shaga) to nitrogen and phosphorus fertilizer rates in Dembia District, northwestern Ethiopia

Tue, 08 Sep 2026 00:00:00 +0000

Rice (Oryza sativa L.) is an important food security crop in Ethiopia, particularly in the Dembia Plain; where productivity remains below its potential because of the lack of site-specific fertilizer recommendations. This study aimed to determine the agronomic and economic optimum rates of nitrogen (N) and phosphorus (P₂O₅) fertilizers for lowland rice production in the Dembia District of northwestern Ethiopia. Field experiments were conducted during the 2021 and 2022 main cropping seasons at two sites using a factorial combination of four N rates (0, 92,184, and 276 kg N ha^-1) and four P₂O₅ rates (0, 23, 46, and 69 kg P₂O₅ ha^-1) arranged in a Randomized Complete Block Design (RCBD) with three replications. Growth, yield, and yield-related parameters were subjected to analysis of variance using R software (version 4.4.2). Grain yield response was evaluated using regression analysis, while economic feasibility was assessed through partial budget analysis. Nitrogen significantly (p < 0.01) influenced all recorded parameters, whereas phosphorus significantly affected effective tiller number, thousand-seed weight, aboveground biomass yield, and grain yield. Grain yield exhibited a significant quadratic response to the interaction of N and P₂O_5, indicating increasing returns up to the optimum level followed by diminishing returns. The highest observed grain yield (4576 kg ha⁻¹) and predicted (4239 kg ha⁻¹) were obtained at the application of 276 kg N ha^-1 combined with 46 kg P₂O₅ ha^-1. However, the partial budget analysis identified the application of 92 kg N ha^-1 combined with 23 kg P₂O₅ ha^-1 as the most economically profitable treatment, providing the highest net benefit (69,760 Birr ha^-1) with an acceptable marginal rate of return (118%). Therefore, the combined application of 92 kg N ha^-1 and 23 kg P₂O₅ ha^-1 is recommended for lowland rice production in the Dembia District and other similar agro-ecologies. Further validation across locations, soil types, and growing seasons is recommended to improve wider applicability.