African Journal of Agriculture

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 106–113

DOI: 10.46882/2026/AJA/000747

Article Type: Original Research Article

Title: Socio-Economic Barriers to Precision Fertilizer Adoption among Smallholder Wheat Growers in the Highlands of Ethiopia

Names of Authors: Berhanu T. Assefa¹, Workneh G. Negatu¹

Authors’ Affiliations: ¹Department of Agricultural Economics, College of Development Studies, Addis Ababa University, Addis Ababa, Ethiopia

Abstract: Blanket fertilizer recommendations across heterogeneous agricultural landscapes lead to nutrient inefficiencies and low wheat yields in the Ethiopian highlands. Precision nutrient management tools, such as the electronic 'Nutrient Expert' decision platform, offer micro-tailored fertilizer recommendations, yet smallholder adoption rates remain low. This study used a multivariate probit model to investigate the socio-economic factors restricting the adoption of precision fertilizer protocols among 450 small-scale wheat growers across the Oromia and Amhara regions. Primary data were gathered via multi-stage random sampling interviews during the 2025/2026 production year. The empirical results revealed that only 18.4% of the sampled farmers systematically applied precision nutrient recommendations. The model demonstrated that formal education, farm size, access to extension agents, and ownership of a smartphone positively and significantly influenced adoption probabilities (p < 0.01). Conversely, the high cost of custom blended fertilizers (± 25.0% higher than standard DAP/Urea) and limited access to local credit lines stood as critical barriers. Farmers utilizing precision models registered a 32.4% yield increase, averaging 4.2 t/ha compared to 3.1 t/ha for blanket application users. The study highlights that bridging the adoption gap requires expanding rural digital access and introducing targeted credit programs to make precision inputs financially accessible.

Keywords: Precision agriculture, Multivariate probit, Nutrient management, Wheat cultivation, Technology adoption, Financial barriers

Manuscript Timeline: Received: May 25, 2026; Revised: June 29, 2026; Accepted: July 24, 2026; Published: August 31, 2026

Citation: Assefa, B. T., & Negatu, W. G. (2026). Socio-Economic Barriers to Precision Fertilizer Adoption among Smallholder Wheat Growers in the Highlands of Ethiopia. African Journal of Agriculture, 13(8), 106–113. DOI: 10.46882/2026/AJA/000747

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 098–105

DOI: 10.46882/2026/AJA/000746

Article Type: Original Research Article

Title: Epidemiology and Molecular Identification of Bacterial Blight (Xanthomonas oryzae pv. oryzae) Strains in Lowland Rice Ecosystems of Uganda

Names of Authors: Godfrey M. Kasenge¹, Proscovia R. Namugga¹, Moses W. Kibwika²

Authors’ Affiliations: ¹National Agricultural Research Organisation (NARO), National Crops Resources Research Institute, Namulonge, Uganda; ²School of Agricultural Sciences, Makerere University, Kampala, Uganda

Abstract: Bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is an escalating biotic threat to lowland rice (Oryza sativa L.) schemes in East Africa. Effective breeding initiatives require a systematic mapping of disease distribution and the molecular diversity of circulating bacterial strains. A diagnostic field survey was executed across 80 irrigated and rainfed lowland rice blocks in eastern and northern Uganda. Disease incidence and severity scores were gathered alongside 120 symptomatic leaf samples. Pathogens were isolated using nutrient agar media, verified via polymerase chain reaction (PCR) using Xoo-specific primers (TXT9A and TXT9B), and genotyped using repetitive sequence-based PCR (rep-PCR). The field survey revealed an average BLB incidence of 54.6%, with the highest severity recorded in the Doho Irrigation Scheme (score of 4.2 on a 1-to-9 scale). PCR amplification confirmed the presence of Xoo in 84.0% of the symptomatic samples. The rep-PCR cluster analysis grouped the isolated strains into three distinct genomic lineages (Lineage I, II, and III). Lineage I was dominant in eastern Uganda and displayed high virulence when inoculated back onto the susceptible local cultivar 'Komboka' under greenhouse conditions. The widespread distribution of highly virulent Xoo strains underscores the urgency of screening regional germplasm pools for durable resistance genes like Xa21.

Keywords: Xanthomonas oryzae, Polymerase chain reaction, Disease severity, Genetic lineage, Lowland rice, Virulence mapping

Manuscript Timeline: Received: May 20, 2026; Revised: June 26, 2026; Accepted: July 20, 2026; Published: August 30, 2026

Citation: Kasenge, G. M., Namugga, P. R., & Kibwika, M. W. (2026). Epidemiology and Molecular Identification of Bacterial Blight (Xanthomonas oryzae pv. oryzae) Strains in Lowland Rice Ecosystems of Uganda. African Journal of Agriculture, 13(8), 098–105. DOI: 10.46882/2026/AJA/000746

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 090–097

DOI: 10.46882/2026/AJA/000745

Article Type: Original Research Article

Title: Effect of Biochar Amendments on Soil Hydraulic Properties and Yield of Maize (Zea mays L.) in an Alfisol of Southwest Nigeria

Names of Authors: Olufemi B. Adeyemi¹, Kazeem A. Shittu¹

Authors’ Affiliations: ¹Department of Soil Science and Land Management, Federal University of Agriculture, Abeokuta, Nigeria

Abstract: Sandy loam Alfisols in southwestern Nigeria suffer from low water retention and rapid nutrient leaching, which undermines rainfed maize production. Biochar application offers a steady pathway to alter soil physical architecture and improve moisture storage. This 2-year field experiment investigated the impact of cocoa pod husk biochar (CPHB) applied at four distinct rates (0, 2.5, 5.0, and 10.0 t/ha) on soil bulk density, saturated hydraulic conductivity (Ksat), moisture retention, and grain yield of maize (Zea mays L.). Soil samples were collected from the 0–15 cm layer post-harvest to determine structural changes. The results indicated that adding 10.0 t/ha of CPHB significantly reduced soil bulk density from 1.48 to 1.26 g/cm³ and lowered Ksat by 42.1% compared to the control, signaling an improvement in micro-pore distribution. Soil water content at field capacity increased significantly from 14.2% to 22.8% w/w in the 10.0 t/ha treated plots. This enhanced moisture buffer protected the crop during mid-season dry spells, leading to a significant increase in mean grain yield (4.12 ± 0.18 t/ha under 10.0 t/ha CPHB vs. 2.34 t/ha in the control; p < 0.01). Maize yield didn't show significant variance between 5.0 and 10.0 t/ha applications, suggesting 5.0 t/ha as an economically optimal rate. Soil organic carbon also expanded by 58.0%, proving that CPHB amendments enhance the climate resilience of tropical Alfisols.

Keywords: Biochar, Bulk density, Soil moisture retention, Alfisol, Maize yield, Crop resilience

Manuscript Timeline: Received: May 15, 2026; Revised: June 22, 2026; Accepted: July 18, 2026; Published: August 30, 2026

Citation: Adeyemi, O. B., & Shittu, K. A. (2026). Effect of Biochar Amendments on Soil Hydraulic Properties and Yield of Maize (Zea mays L.) in an Alfisol of Southwest Nigeria. African Journal of Agriculture, 13(8), 090–097. DOI: 10.46882/2026/AJA/000745

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 082–089

DOI: 10.46882/2026/AJA/000744

Article Type: Original Research Article

Title: Post-Harvest Loss Assessment and Mitigation Strategies for Smallholder Mango (Mangifera indica L.) Value Chains in Eastern Kenya

Names of Authors: Josphat K. Mutua¹, Agnes W. Mwang'ombe¹, Solomon I. Shibairo²

Authors’ Affiliations: ¹Department of Plant Science and Crop Protection, University of Nairobi, Nairobi, Kenya; ²Faculty of Agriculture, Kibabii University, Bungoma, Kenya

Abstract: Post-harvest losses severely depress the economic returns of smallholder mango (Mangifera indica L.) growers across East Africa, with waste often driven by poor handling and inadequate cold storage. This study quantified physical and quality losses along the mango value chain in Machakos County, Kenya, and evaluated the efficacy of low-cost evaporative cooling chambers (ECC) combined with hexanal vapor treatments to extend shelf life. Quantitative loss assessments were tracked across three primary hubs: harvesting, transit, and rural wholesale markets. Freshly harvested 'Apple' mango fruits were treated with 0.02% v/v hexanal vapor for 4 hours and stored either inside a charcoal-walled ECC (mean temperature 21.4 ± 1.2 °C, relative humidity 84.5%) or under ambient room conditions (mean temperature 29.2 ± 1.8 °C, relative humidity 54.2%). Value chain tracking revealed a cumulative post-harvest loss of 38.4%, with the highest single-point loss occurring during rural marketing (18.2%). Combining hexanal vapor with ECC storage significantly delayed fruit softening, weight loss, and chlorophyll degradation (p < 0.05). Mangoes subjected to the combined treatment maintained standard market firmness and total soluble solids (14.2 °Brix) for up to 24 days, compared to only 8 days for control fruits stored under ambient conditions. Implementing this integrated low-cost post-harvest protocol can dramatically cut economic losses, stabilize market supply, and lift smallholder net revenues by an estimated 26.0%.

Keywords: Mangifera indica, Evaporative cooling, Hexanal vapor, Shelf life, Value chain, Quality retention

Manuscript Timeline: Received: May 12, 2026; Revised: June 20, 2026; Accepted: July 15, 2026; Published: August 30, 2026

Citation: Mutua, J. K., Mwang'ombe, A. W., & Shibairo, S. I. (2026). Post-Harvest Loss Assessment and Mitigation Strategies for Smallholder Mango (Mangifera indica L.) Value Chains in Eastern Kenya. African Journal of Agriculture, 13(8), 082–089. DOI: 10.46882/2026/AJA/000744

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 074–081

DOI: 10.46882/2026/AJA/000743

Article Type: Original Research Article

Title: Phenotypic Diversity and Agronomic Characterization of Local Bambara Groundnut (Vigna subterranea L. Verdc) Landraces in Southern Zambia

Names of Authors: Chileshe M. Mwaba¹, Sitali S. Mubita¹

Authors’ Affiliations: ¹Department of Plant Science, School of Agricultural Sciences, University of Zambia, Lusaka, Zambia

Abstract: Bambara groundnut (Vigna subterranea L. Verdc) is an underutilized, highly drought-tolerant indigenous African legume capable of yielding well in nutrient-poor soils. Despite its food security value, it lacks structured breeding programs, leaving farmers reliant on uncharacterized local landraces. This study evaluated the phenotypic diversity and agronomic traits of 32 Bambara groundnut landraces collected from smallholders across southern Zambia. The field evaluation used a randomized complete block design with three replications. Quantitative and qualitative traits were documented following standard Bioversity International descriptors. High phenotypic variability was observed across all quantitative parameters (p < 0.01). Days to 50% flowering ranged from 42 to 58 days, while 100-seed weight varied between 38.4 and 72.5 g. Principal Component Analysis (PCA) demonstrated that the first three principal components accounted for 74.8% of the total morphological variance, driven primarily by seed weight, shell thickness, pod count per plant, and canopy spread. Cluster analysis divided the 32 landraces into four distinct morphological groups. Cluster II comprised early-maturing, high-yielding landraces that averaged 1.84 t/ha under rainfed conditions, making them ideal candidates for immediate breeding initiatives. These results highlight a rich genetic reservoir within local Zambara Bambara groundnut stocks that can be leveraged to develop resilient legume varieties for semi-arid zones.

Keywords: Vigna subterranea, Underutilized legumes, Phenotypic diversity, Principal component analysis, Landraces, Agronomic yield

Manuscript Timeline: Received: May 10, 2026; Revised: June 18, 2026; Accepted: July 12, 2026; Published: August 28, 2026

Citation: Mwaba, C. M., & Mubita, S. S. (2026). Phenotypic Diversity and Agronomic Characterization of Local Bambara Groundnut (Vigna subterranea L. Verdc) Landraces in Southern Zambia. African Journal of Agriculture, 13(8), 074–081. DOI: 10.46882/2026/AJA/000743

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 066–073

DOI: 10.46882/2026/AJA/000742

Article Type: Original Research Article

Title: Impact of Climate Smart Agriculture Practices on Household Food Security among Smallholder Yam Farmers in Central Nigeria

Names of Authors: Olorunfemi J. Ayeni¹, Emeka C. Nwosu¹, Blessing O. Ibrahim²

Authors’ Affiliations: ¹Department of Agricultural Economics, University of Abuja, Abuja, Nigeria; ²Federal Ministry of Agriculture and Food Security, Abuja, Nigeria

Abstract: Vulnerability to climate shocks routinely threatens smallholder yam (Dioscorea rotundata) production, a major staple food and income source across Nigeria's middle belt. Adopting Climate-Smart Agriculture (CSA) practices is widely promoted to reduce these risks, but empirical evidence linking adoption to measurable food security gains remains limited. This study investigated the factors driving CSA adoption and measured its impact on household food security among 420 yam farmers in central Nigeria. The surveyed practices included minimum tillage, intercropping with legumes, mulching, and using early-maturing varieties. An Endogenous Switching Regression (ESR) framework was employed to account for unobserved self-selection bias among adopters. The empirical models revealed that access to agricultural extension services, ownership of a mobile phone, and secure land tenure significantly increased the probability of adopting multiple CSA practices (p < 0.05). The ESR model showed that adopting CSA practices generated an average 28.4% increase in yam yields per hectare. Furthermore, household indicators revealed that adoption increased daily per capita calorie intake by 412 kcal and lowered the Household Food Insecurity Access Scale (HFIAS) score from 8.4 down to 3.2. These results confirm that climate-smart yam cultivation significantly strengthens household food security and climate resilience, emphasizing the need for targeted extension campaigns.

Keywords: Climate-smart agriculture, Endogenous switching, Dioscorea rotundata, Food security, Household assets, Impact assessment

Manuscript Timeline: Received: May 02, 2026; Revised: June 10, 2026; Accepted: July 04, 2026; Published: August 22, 2026

Citation: Ayeni, O. J., Nwosu, E. C., & Ibrahim, B. O. (2026). Impact of Climate Smart Agriculture Practices on Household Food Security among Smallholder Yam Farmers in Central Nigeria. African Journal of Agriculture, 13(8), 066–073. DOI: 10.46882/2026/AJA/000742