Browsing by Author "Okeyo, Jeremiah"

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    Farming systems’ typologies analysis to inform agricultural greenhouse gas emissions potential from smallholder rain-fed farms in Kenya
    (Elsevier B.V, 2020) Musafiri, Collins M.; Macharia, , Joseph M.; Ng’etich, Onesmus K.; Kiboi, Milka N.; Okeyo, Jeremiah; Shisanya, Chris A.; Okwuosa, , Elizabeth A.; Mugendi, Daniel N.; Ngetich, Felix K.
    Most sub-Saharan Africa smallholder farming systems are highly heterogeneous. Direct quantification of greenhouse gas emissions from these farming systems is hampered by di- versity at farm-level. Each farm contributes differently to greenhouse gas (GHG) emissions and consequently GHG inventories. Typologies can be used as a mechanism of addressing farming systems’ heterogeneity by grouping them into specific farm types. With the GHG quantification simplification initiatives in mind, we developed smallholder farm typologies based on soil fertility inputs. We assessed nitrogen application rate, soil fertility manage- ment technologies and the socio-economic factors diversity among the farm typologies in the central highlands of Kenya. We used data from a cross-sectional household survey with a sample size of 300 smallholder farmers. We characterized the farm types using princi- pal component analysis (PCA). To develop farm typologies, we subjected the PCA-derived typologies related factors to cluster analysis (CA). The results showed six farm types: Type 1, comprising cash crop and hybrid cattle farmers; Type 2, comprising food crop farmers; Type 3, composed of coffee-maize farmers; Type 4, comprising millet-livestock farmers; Type 5, comprising highly diversified farmers, and Type 6, comprising tobacco farmers. Land size owned, total tropical livestock unit, the proportion of land and nitrogen applied to different cropping systems were significant in the construction of farm typologies. Uni- variate analysis showed the household head’s level of education, hired labour, group mem- bership, access to extension services, and proportion of income from cropping activities as critical factors influencing farm typologies in the study area. This study demonstrates the importance of smallholder farm typologies in identifying greenhouse gas emissions hotspots, designing quantification experiment and policy framing. We concluded that poli- cies and intervention measures targeting climate-smart agriculture at smallholder farms
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    Impact of reduced tillage and crop residue management on soil properties and crop yields in a long-term trial in western Kenya
    (2015-11) Okeyo, Jeremiah; Norton, Jay; Koala, Saidou; Waswa, Boaz; Kihara, Job; Bationo, Andre
    Sustainable farming practices are required to address the persistent problems of land degradation and declining crop productivity in sub-Saharan Africa (SSA). Approaches such as reducing tillage and retaining crop residues as mulch are potential entry points for smallholder farmers to move towards sustainability. In this study, we assessed the impact of reduced tillage (RT) versus conventional tillage (CT), each combined with crop residue reapplication, on soil quality indicators and crop yields under an eight-year trial in western Kenya. Our results indicate that RT combined with crop residue reapplication enhanced physical soil quality through increased macro-aggregate (>2000 µm) proportions and mean weight diameter (MWD). Similarly, lower respiratory quotient (qCO2) values indicate that soil microbes under RT have better substrate use efficiency compared with those under CT. Nevertheless, soil organic carbon (SOC), potentially mineralizable C (PMC), microbial biomass C (MBC) and mineral nitrogen contents were all higher under CT with crop residue incorporated into the soil. Maize grain yield and above-ground biomass were also higher under CT. Thus, despite RT showing potential to improve soil physical properties, CT performed better. A step-wise approach is proposed towards the practice of conservation agriculture under resource constrained smallholder farming conditions, starting with increased biomass production to provide crop residue for soil cover, then followed by reduced tillage approaches.