Research Article
Influence of Manure Management Practices on Methane Emissions in Smallholder Dairy System, Northern Tanzania
Issue:
Volume 11, Issue 4, August 2026
Pages:
65-75
Received:
9 June 2026
Accepted:
29 June 2026
Published:
22 July 2026
Abstract: The expansion of smallholder dairy farming in the developing countries is associated with an increase in manure production. However, the poor management of manure leads to an increase in methane gas emissions. This study was designed to evaluate methane gas emission from manure under different manure management practices in the smallholder dairy farms in Arusha City (urban) and Arusha District Council (peri-urban), Northern Tanzania. Data were collected through a semi- structured questionnaire, and the Intergovernmental Panel on Climate Change (IPCC) tier two methodology was used to estimate methane gas emissions from different manure management systems, including solid storage, daily spread, anaerobic digester, composting and slurry. Data on the dairy herds’ structure and the manure management system were analysed using Chi-square. The general linear model (GLM) of the statistical package of social sciences (SPSS) was used to estimate the effect of feed types and manure management systems on manure composition and methane gas emission from different management practices. The result revealed that there were significant differences in nutritional composition across feed types. There was a significant difference in dairy herd structure where urban farmers had more lactating cows, heifers and calves than those farmers in peri-urban areas. Furthermore, feed type significantly influenced manure composition, particularly volatile solids (VS) and total carbon (TC). Additionally, there were significant differences in manure composition across the manure management system in terms of volatile solids, pH, moisture, total organic matter, and total carbon. Methane gas emissions differed significantly across the manure management practices (P <0.05). The daily spread had less emission of 0.14 kg CH4 head-1year-1 which was attributed to aerobic conditions that limit methane emission, while higher emission from other management systems was due to anaerobic conditions that facilitate emissions. In conclusion, a significant variation in methane emissions was found among the manure management systems, with the highest emissions occurring in the slurry management system and the lowest in the daily spread system. The study recommends the anaerobic digestion system than over daily spread system because previous studies showed that anaerobic digester system not only mitigates methane gas emissions among smallholder dairy farmers but also optimizes the value of manure, while daily spread leads to water pollution due to runoff to surface water resources, hence causing waterborne diseases to both humans and animal.
Abstract: The expansion of smallholder dairy farming in the developing countries is associated with an increase in manure production. However, the poor management of manure leads to an increase in methane gas emissions. This study was designed to evaluate methane gas emission from manure under different manure management practices in the smallholder dairy fa...
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Research Article
Soil Resource Characterization, WRB Classification and Mapping of Guto Gida District, Western Oromia, Ethiopia
Issue:
Volume 11, Issue 4, August 2026
Pages:
76-94
Received:
8 July 2026
Accepted:
21 July 2026
Published:
10 August 2026
Abstract: Accurate and spatially explicit information on soil properties is essential for sustainable land-use planning and the development of site-specific soil management strategies. This study aimed to characterize, classify, and map the soil resources of the Guto Gida district in Western Oromia, Ethiopia. A semi-detailed soil survey was conducted, delineating 28 Soil Mapping Units (SMUs). Twenty representative pedons were described in the field for morphological attributes and analyzed in the laboratory for key physicochemical properties. The soils were predominantly deep to very deep (>150 cm), except for Leptosols occurring on steep dissected landscapes. Morphologically, most pedons exhibited reddish to reddish-brown hues (2.5YR–5YR), reflecting well-drained conditions and the presence of iron oxides. Soil texture was largely dominated by clay, and low silt: clay ratios (<0.35) indicated advanced weathering and clay translocation. Soil reaction (pH-H₂O) ranged from strongly acidic (4.66 in SMU 26) to slightly acidic (6.36 in SMU 23), with substantial portions of the landscape affected by acidity, as evidenced by high exchangeable acidity values reaching up to 10.49 cmolc kg⁻¹in SMU 27. Organic carbon and total nitrogen contents were generally low to moderate, while available phosphorus was critically low (<10 ppm) in most pedons due to the strong P-fixing capacity of the clay-rich, acidic soils. Based on the World Reference Base for Soil Resources (WRB, 2022), the soils were classified into eight Reference Soil Groups: Nitisols (41.59%), Alisols (14.73%), Cambisols (15.37%), Lixisols (13.95%), Leptosols (4.54%), Luvisols (3.53%), Acrisols (2.89%), and Regosols (0.88%). Overall, soil acidity and nutrient depletion constitute the major limitations to agricultural productivity in the district. Integrated Soil Fertility Management (ISFM), encompassing liming, organic matter enhancement, and site-specific fertilization, is recommended for the strongly acidic Alisols and Acrisols, whereas targeted soil and water conservation strategies are critical for the sloping landscapes dominated by Nitisols and Lixisols.
Abstract: Accurate and spatially explicit information on soil properties is essential for sustainable land-use planning and the development of site-specific soil management strategies. This study aimed to characterize, classify, and map the soil resources of the Guto Gida district in Western Oromia, Ethiopia. A semi-detailed soil survey was conducted, deline...
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,
David Dawson Maleko
