Browsing by Author "Kiboi, M.N."
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Item Economic Evaluation and Socioeconomic Drivers Influencing Farmers’ Perceptions on Benefits of Using Organic Inputs Technologies in Upper Eastern Kenya(Elsevier B.V., 2021-09-06) Mwaura, G.G.; Kiboi, M.N.; Mugwe, J.N.; Nicolay, G.; Bett, E.K.; Muriuki, A.; Musafiri, C.M.; Ngetich, F.K.; Kenyatta University ; University of Embu ; Cortile Scientific Company Ltd ; Research Institute of Organic Agriculture (FiBL) ; Kenya Agricultural and Livestock Research Organization ; Jaramogi Oginga Odinga University of Science and Technology (JOOUST)Declining soil fertility in Sub-Saharan Africa (SSA) is a significant constraint towards increasing agricultural productivity. Soil fertility decline coupled with rapid population growth and low use of organic soil fertility technologies has threatened the population’s economic status that lives in the rural area and relies on rain-fed agriculture. We conducted a cross-sectional household survey in the Central Highlands of Kenya (Gatanga and Meru South sub-counties) to determine farmers’ perception of the benefits of using organic resources technologies, socioeconomic drivers influencing their perceptions, and financial returns from the technologies. The selected technologies were; sole animal manure and a combination of animal manure with inorganic fertilizer. We based the benefits of using the selected soil fertility management technologies on four variables; potential to improve soil fertility, crop yields, profitability, and labor requirement. The majority of the farmers strongly agreed that using the selected technologies improved soil fertility, crop yields and were profitable. On the contrary, they agreed it was labor-intensive. Gender of the household head, household size, Tropical Livestock Unit (TLU), access to external labor, access to credit, total land cultivated, age, and years of farming experience were the socioeconomic drivers that significantly influenced farmers’ perception of the use of sole animal manure and animal manure combined with inorganic fertilizer. Results showed that animal manure had the highest financial returns of US$ 440.74 in Gatanga, while in Meru South, animal manure combined with inorganic fertilizer had the highest returns of US$ 456.25. The study highlights that the use of sole animal manure and animal manure combined with inorganic fertilizer is perceived positively by the smallholder farmers and has better financial returns than sole inorganic fertilizer. Thus, the use of selected organic resource technologies should be encouraged by creating more awareness through farmers’ training programs.Item Greenhouse Gas Fluxes from Selected Soil Fertility Management Practices in Humic Nitisols of Upper Eastern Kenya(MDPI, 2022-02-08) Githongo, M.W.; Musafiri, C.M.; Macharia, J.M.; Kiboi, M.N.; Fliessbach, A.; Muriuki, A.; Ngetich, F.K.; University of Embu ; Cortile Scientific Limited ; Kenyatta University ; Research Institute of Organic Agriculture (FIBL) ; Kenya Agricultural and Livestock Research Organization - National Agriculture Research Laboratories ; Jaramogi Oginga Odinga University of Science and Technology (JOOUST)We quantified the soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes of five soil fertility management practices (inorganic fertilizer (Mf), maize residue + inorganic fertilizer (RMf), maize residue + inorganic fertilizer + goat manure (RMfM), maize residue + tithonia diversifolia + goat manure (RTiM), and a control (CtC)) in Kenya’s central highlands using a static chamber method from March 2019 to March 2020. The cumulative annual soil CH4 uptake ranged from −1.07 to −0.64 kg CH4-C ha−1 yr−1, CO2 emissions from 4.59 to 9.01 Mg CO2-C ha−1 yr−1, and N2O fluxes from 104 to 279 g N2O-N ha−1 yr−1. The RTiM produced the highest CO2 emissions (9.01 Mg CO2-C ha−1 yr−1), carbon sequestration (3.99 Mg CO2-eq ha−1), yield-scaled N2O emissions (YSE) (0.043 g N2O-N kg−1 grain yield), the lowest net global warming potential (net GWP) (−14.7 Mg CO2-eq ha−1) and greenhouse gas intensities (GHGI) (−2.81 Kg CO2-eq kg−1 grain yield). We observed average maize grain yields of 7.98 Mg ha−1 yr−1 under RMfM treatment. Integrating inorganic fertilizer and maize residue retention resulted in low emissions, increased soil organic carbon sequestration, and high maize yieldsItem Soil Management Strategies Enhanced Crop Yield, Soil Moisture, and Water Productivity in Nitisols of Upper Eastern Kenya(Elsevier B.V., 2021-12) Oduor, N.; Kiboi, M.N.; Muriuki, A.; Adamtey, N.; Musafiri, C.M.; Ngetich, F.K.; University of Embu ; Cortile Scientific ; Kenya Agricultural and Livestock Research Organization ; Research Institute of Organic Agriculture (FiBL) ; Jaramogi Oginga Odinga University of Science and Technology (JOOUST)Low soil moisture and declining crop yield caused by erratic rainfall, and poor soil management practises con- tribute to the continuous decrease in water productivity. We sought to assess the effects of the selected soil man-agement strategies on crop yield, soil moisture, and water productivity in the Nitisols. We carried out the study in Chuka, Tharaka-Nithi County, and Kandara, Murang’a County. The experiment was laid in a split-plot design. Minimum and conventional tillage were the main treatments, while soil fertility inputs were the sub-treatments. The soil fertility inputs included sole mineral fertilizer, mineral fertilizer plus animal manure, mineral fertilizer plus crop residue, Tithonia diversifolia plus phosphate rock (Minjingu), sole animal manure intercropped with Dolichos Lablab L.. Maize grain, stover yield, soil moisture, and water productivity significantly increased by 6– 22, 10, and 31–33% under conventional tillage than minimum tillage. Mineral fertilizer with or without organic inputs and with or without crop residue mulch significantly (p>0.0002) enhanced maize grain yield by 96 –729% and stover yield by 79 -276% compared to the control in the two sites during the experimental period. Soil fertility inputs significantly increased soil moisture at 0–20 cm depth at the Chuka site by 10 - 40%. Water productivity was significantly (p > 0.0001) improved under mineral fertilizer with or without organic inputs and with or without crop residue mulch by 46 - 279% in both sites. Generally, the combination of organic and inor-ganic resources plus crop residue mulch enhanced soil water productivity irrespective of the tillage method. Their use should be encouraged for improved water productivity. However, tillage effects on crop yield, soil moisture, and water productivity should be investigated under long-term conditions.Item Soil Organic Carbon Stocks under Different Land Utilization Types in Western Kenya(MDPI, 2022-07-06) Kibet, E.; Musafiri, C.M.; Kiboi, M.N.; Macharia, J.; Ng’etich, O.K.; Kosgei, D.K.; Mulianga, B.; Okoti, M.; Zeila, A.; Ngetich, F.K.; University of Embu ; Cortile Scientific ; KCA University ; Kenyatta University ; Moi University ; Kenya Agricultural and Livestock Research Organization (KALRO) ; The World Bank ; Jaramogi Oginga Odinga University of Science and Technology (JOOUST)The up-surging population in sub-Saharan Africa (SSA) has led to the conversion of more land for agricultural purposes. Resilient land utilization types that input carbon to the soil are key in enhancing climate change mitigation. However, there are limited data on different land utilization types’ contribution to climate mitigation through carbon input to soils. The study aims to quantify carbon stock across different land utilization types (LUT) practiced in Western Kenya. The following land utilization types were studied: agroforestry M (agroforestry with Markhamia lutea), sole sorghum, agroforestry L (agroforestry with Leucaena leucocephalaI), sole maize, and grazing land replicated thrice. To determine soil bulk density, SOC concentration, and soil carbon stock, soil samples were collected at depths of 0–5, 5–10, 10–20, and 20–30 cm from different LUTs. A PROC ANOVA was used to determine the difference in soil bulk density, SOC, and SOC stock between different LUTs and depths. The four variables differed across the LUTs and depths. A high soil bulk density was observed at 0–5 cm under grazing land (1.6 g cm−3) and the lowest under agroforestry M (1.30 g cm−3). Conversely, the soil bulk density was low at 20–30 cm under grazing land. The 0–5 cm depth accounted for a high share of SOC and SOC stock under Agroforestry M, while the 10–20 and 20–30 cm depth accounted for the high share of SOC stock under agroforestry L. The study showed differences in SOC across the different depths and LUTs. The findings highlight that agroforestry L and agroforestry M are promising interventions toward climate mitigation through carbon induction to soils.Item The Effect of Minimum Tillage and Animal Manure on Maize Yields and Soil Organic Carbon in Sub-Saharan Africa: A Meta-Analysis(Elsevier B.V., 2021-12) Githongo, M.W.; Kiboi, M.N.; Ngetich, F.K.; Musafiri, C.M.; Muriuki, A.; Fliessbach, A.; University of Embu ; Cortile Scientific Limited ; Jaramogi Oginga Odinga University of Science and Technology (JOOUST) ; Kenya Agricultural and Livestock Research Organization ; Research Institute of Organic Agriculture FIBLIn sub-Saharan Africa (SSA), diminishing soil fertility has been experienced from continuous cropping and low nutrient replacement. Organic inputs and minimum tillage are proposed to increase the declining fertility of the soil to increase crop growth and yields. We reviewed animal manure and minimum tillage use on maize yields and soil organic carbon (SOC) in SSA. This involved a meta-analysis on the influence of minimum tillage and animal manure on maize grain yields and SOC. Reported data on maize yields and soil organic carbon were extracted from figures, tables, and text, of the selected studies. These studies were analyzed using R, and results were presented in a forest plot. Minimum tillage had no significant influence on maize yields and soil organic carbon. Animal manure significantly improved maize yields and soil organic carbon. The study underscored the importance of animal manure in improving maize yields and soil organic carbon in SSA. Animal manure application in maize cropping systems is plausible to increase maize yields and soil organic carbon in SSA.Item Tillage System and Integrated Soil Fertility Inputs Improve Smallholder Farmers’ Soil Fertility and Maize Productivity in the Central Highlands of Kenya(Journal of Agriculture and Rural Development in the Tropics and Subtropics, 2021-09-20) Otieno, E.O.; Ngetich, F.K.; Kiboi, M.N.; Muriuki, A.; Adamtey, N.N.; University of Embu ; Kenyatta University ; Jaramogi Oginga Odinga University of Science and Technology (JOOUST) ; Kenya Agricultural and Livestock Research Organization (KALRO-NARL) ; Research Institute of Organic Agriculture (FiBL)We designed and implemented an on-farm trial in Meru South and Gatanga sub-counties to understand the effects of integrated soil fertility management (ISFM) technologies on soil nitrogen (N), phosphorus (P), potassium (K), and maize productivity. The technologies included combinations of mineral fertiliser and maize stover (CrMf); crop residue, Tithonia diversifolia and rock phosphate (CrTiP); crop residue, Tithonia diversifolia and goat manure (CrTiMan); crop residue, inorganic fertiliser and goat manure (CrMfMan); crop residue, goat manure and Dolichos lablab (CrManLeg), and sole inorganic fertiliser (Mf) executed under conventional (ConC) and minimum (MinTill) tillage methods. We interviewed the farmers who participated in implementing the trials at the end of the study to understand the likelihood to uptake the technologies. We observed that the technologies increased soil N, P, K, and maize productivity compared to ConC (the control). There was a high likelihood of uptake of high-performing ISFM technologies. We recommend CrTiP for the two sub-counties for the short-term. However, a long-term experiment is needed to evaluate performances of CrTiMan, CrTiP, CrMfMan, and CrManLeg under the two tillage methods for site-specific recommendations taking into consideration rainfall variations.Item Uptake of Integrated Soil Fertility Management Technologies in Heterogeneous Smallholder Farms in Sub-Humid Tropics(Elsevier B.V., 2021-12) Otieno, E.O.; Kiboi, M.N.; Gian, N.; Muriuki, A.; Musafiri, C.M.; Ngetich, F.K.; University of Embu ; Kenyatta University ; Cortile Scientific Limited ; Research Institute of Organic Agriculture (FiBL) ; Kenya Agricultural and Livestock Research Organization ; Jaramogi Oginga Odinga University of Science and Technology (JOOUST)Low soil fertility strongly affects environmental sustainability and Sustainable Development Goals (SDGs) worldwide. Integrated soil fertility management (ISFM) is a potential remedy for declining soil fertility. We addressed determinants of ISFM technologies and identified the sources of soil fertility information using cluster and ordered probit analyses in two counties of the Central Highlands of Kenya. In Tharaka-Nithi county, the uptake of ISFMclass1 (Animal manure +anti-erosion + inorganic fertilizer +crop rotation + legume intercrop), positively correlated with membership to cooperatives, religious groups, SACCOs, and ownership of wheelbarrow but negatively associated with gender, level of education, low farming experience and increased off-farm income. The uptake of ISFMclass2 (Compost +Tithonia diversifolia +minimum tillage +agroforestry + crop residue retention) significantly correlated with religious group membership and ownership of radio. The uptake of ISFMclass3 (sole green manure) positively correlated with a household with an adult offering outside labor but negatively associated with distance to agro-dealers. In Murang'a, ISFMclass2 (Animal manure +inorganic fertilizer +anti-erosion + legume intercrop) is positively associated with farmers' age, membership to cooperatives, television ownership, and access to handhoe and distance to tarmacked roads. Access to drought power, distance to tarmacked road, and buyers positively correlated with ISFMclass1 (Agroforestry +green manure +minimum tillage +crop residue retention + crop rotation). There was a positive correlation between access to drought power and uptake of ISFMclass3 that combined compost and Tithonia diversifolia. We conclude that the region's uptake of unique ISFM combinations is influenced by socioeconomic, bio-physical determinants, and farmers' perception of soil fertility status. We thus recommend that increased upscaling of uptake of unique combinations of ISFM technologies require robust collaboration among various local development stakeholders to address the prohibitive factors while strengthening enabling ones.
