Fertility Management Technologies Research Articles

THE EFFECTS OF INTEGRATED SOIL FERTILITY MANAGEMENT AND CROPPING SYSTEMS ON SOIL WATER CONTENT ON SORGHUM AND COWPEA PRODUCTION IN CENTRAL HIGHLANDS OF KENYA

<p><strong>Background:</strong> Soil fertility degradation remains the major biophysical cause of declining <em>per capita</em> crop production on smallholder farmers in Central Kenya highlands. The study was carried out for 3 consecutive seasons in Embu County classified as semi-arid lands in Kenya. <strong>Objectives:</strong> To determine the effect of Soil Water Harvesting (SWH), cropping systems and Integrated Soil Fertility Management technologies on sorghum and cowpea production in Mbeere South Sub-County, Kenya. <strong>Methodology:</strong> The treatments were arranged in a factorial structure with 3 levels of SWH, 2 cropping systems and 6 soil fertility management options laid out in a partially balanced incomplete block design. The SWC was measured after 2 weeks after planting interval stages in the whole season. Data were analyzed by ANOVA and significant means separated using Least Significant Difference (LSD) at 95% Confidence Interval. <strong>Results:</strong> There was a two way interactions effect between SWH*Fertility management options on sorghum grain yields was significant (<em>p</em>=0.0027, <em>p</em>=0.0008 and<em> p</em>=0.0057) during long rains (LR) of 2011 and 2012, and short rains (SR) of 2011, respectively. Additionally, SWH methods significantly affected sorghum grain yields in a similar trend (<em>p</em>=0.002, <em>p</em>=0.0005 and<em> p</em>=0.0003) in their respective seasons. In SR 2011 and LR 2012, soil fertility options also produced significant effects (<em>p</em>=0.0047 and <em>p</em>=0.0024) on cowpea grain yields, respectively. The results further indicated that there were significant higher SWC measurements at initial stages of 2 WAP, 4 WAP and 6 WAP intervals as compared to the late stages of the season. However, sole cropping systems had significantly more SWC measurement than those in intercropping systems in both seasons. <strong>Implications:</strong> Manure added treatments positively affected SWC conservation and this could be as a result of increased soil organic carbon which improved soil fertility. The available SWC played a great role in drought effect mitigation by availing moisture to sorghum and cowpea productivity especially when prolonged dry spells coincide with crop’s sensitive phenological growing stages. <strong>Conclusions:</strong> Water harvesting methods cropping systems and soil fertility management options had positive influence on soil moisture conservation and crop yields production in Central Kenya Highland. </p>

Cultivating sustainability: Adoption and intensity of soil fertility management technologies among rural farms in Zambia

Despite the numerous advantages of soil fertility management (SFM) practices and substantial investments to promote adoption, uptake of these technologies remains low across sub-Saharan Africa. We study the adoption and intensity of key SFM practices - improved fallow, animal manure, compost, crop residue retention, minimum tillage, inorganic fertilizer, and intercropping among rural farmers in Zambia. Data from 1234 rural farms and the multivariate probit (MVP) and generalized Poisson regression models are used. The MVP model highlights interconnections among practices, emphasizing the need for integrated interventions. Socio-demographics like gender, age, education, and household labor availability significantly influence adoption of SFM practices. Farm characteristics including experience, land ownership, livestock, and off-farm income also play pivotal roles. Accessibility of information via phones, radio, and farmer groups emerged as a crucial enabler, while extension services, credit, and proximity to markets and roads shape adoption decisions. Results indicate education, household labor, off-farm income, and group membership drive intensity of adoption. Extension contacts, training, and agro-ecological region location also affect intensity with regional variations. Key policy implications emerge. First, the complementarities among practices underscore the need for holistic strategies recognizing these synergies. Second, enhancing education specifically for younger farmers can promote adoption of SFM technologies by increasing knowledge. Third, spurring farmer groups facilitates knowledge exchange, input access, and collaborative adoption. Fourth, strategic extension services and training programs are vital to address knowledge gaps for sustained adoption. Overall, this study provides insights to guide policies for promoting SFM practices among rural farms.

Influence of soil fertility management technologies on phosphorus fractions, sorption characteristics, and use efficiency in humic Nitisols of Upper Eastern Kenya

Fractions of phosphorus (P) and its sorption characteristics are affected by different soil fertility (FM) technologies which ultimately affect crop growth and productivity. However, the response of P fractions and sorption characteristics to soil fertility technologies that integrate diverse amendments is still poorly understood in acidic Nitisols. A randomized complete block design was layout in an acidic Nitisol to determine fractions of P, its sorption characteristics and use efficiencies in acidic Nitisols under various FM technologies in field conditions. The use of minimum tillage + maize residue + inorganic fertilizer + goat manure (MTCrGF) had the highest impact on and significantly increased resin-Pi, NaHCO3-Pi, and maximum P sorption (Smax) by 182, 76, and 52 mg P kg−1. Moreover, NaOH-Pi and Smax concentrations were higher under conventional tillage + maize residue + inorganic fertilizer + goat manure (CTCrGF) by 216 mg P kg−1 and 49 mg P kg−1 than the control. MTCrGF and CTCrGF also had the lowest P bonding energy (0.04 L mg−1). CTCrGF had the highest P partial productivity factor (0.093 and 0.140 kg biomass kg−1 P) and P agronomic efficiency (0.080 and 0.073 kg biomass kg−1 P) during the two cropping seasons. The results demonstrate the positive influence of combining multiple P sources on soil P fractions, sorption characteristics, and use efficiencies. Notably, combining either conventional or minimum tillage with maize straw and applying integrated manure and inorganic fertilizer (MTCrGF or CTCrGF) can increase the labile P concentrations and reduce the potential depletion of the non-renewable rock phosphate and the use of inorganic phosphatic fertilizers for agricultural production.

The effect of organic and inorganic soil fertility management technologies on smallholder farmers’ net revenue and nutrition security: Evidence from southwest region of Ethiopia

Technologies are better evaluated as packages, i.e., bundles of adoption decisions, rather than a segregate adoption, given the preeminent effect of the combinations on food and nutrition security, productivity, and other welfare outcomes. This study therefore assessed the effect of organic and inorganic soil fertility management technologies on net revenue and Nutrition security of smallholder farmers in Southwest Ethiopia. A multinomial endogenous switching regression (MESR) model, which captures both self-selection bias and the interactions between choices of alternative packages, was applied for this study since farmers’ adoption decisions are likely influenced by unobservable characteristics that may be correlated with the outcomes of interest. The investigation result revealed that, from the three adoption combinations of organic and inorganic soil fertility management technologies, joint adoption of the two technology groups was found to have a significant effect on both net revenue and Nutrition security simultaneously. Unlikely, the isolated adoption of the two soil fertility management technologies may not result in an intended nutrition security outcome. Thus, for the simultaneous improvement in net revenue and nutrition security, the study recommends concentrating on the joint practice of the two organic and inorganic soil fertility management technologies.

Determinants of adoption and adoption intensity of integrated soil fertility management technologies among sorghum farmers in Upper Eastern Kenya

AbstractClimate change manifestations and population pressure are some of the most critical challenges that affect agricultural productivity. Integrated soil fertility management (ISFM) technologies are among the agricultural innovations that have been developed to address declining crop productivity. These technologies have been promoted across diverse areas including marginal agro‐ecological zones. Despite the nobility and versatility of ISFM technologies, their adoption is still low particularly across Kenya landscapes. Consequently, there is limited knowledge explaining the adoption of these technologies especially in the dry areas. This study therefore, applied Cragg's Double Hurdle model to determine the factors affecting adoption and adoption intensity of ISFM technologies among farmers in Upper Eastern Kenya, who mainly grow sorghum both as a food and a cash crop. The results revealed that gender, dependants, farming goal for subsistence purpose (p < .01), decision on information use, farm size, extension services, research awareness, ISFM awareness and ISFM access, significantly affected household decision on adoption of ISFM technologies. On the other hand, gender of household head, farm size, main source of agricultural information and formal agricultural training had significant influence on adoption intensity of ISFM technologies. There is a thus a crucial need for integration of determinants surrounding adoption and adoption intensity of ISFM technologies in policy making and planning processes to enhance sorghum crop productivity in marginal Upper Eastern areas of the country.

Influence of farmers’ socio-economic characteristics on nutrient flow and implications for system sustainability in smallholdings: a review

The rise in global human population, coupled with the effects of climate change, has increased the demand for arable land. Soil fertility has been the most affected, among other things. Many approaches to soil fertility management have been proposed by studies in Sub-Saharan Africa (SSA); however, the question of sustainability remains. Nutrient monitoring (NUTMON), which combines biophysical and socio-economic features for soil fertility management, gives an in-situ soil fertility status of a given land use system, which ultimately provides guidance in proposing appropriate soil management techniques in a given land use system. In this review, the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) approach was deployed for a systematic search of the literature materials. The review evaluated various studies on nutrient monitoring in SSA soils in order to understand the socioeconomic attributes and their influence on farming systems, as well as nutrient flow and balances. The review identified two dominant smallholder farming systems in SSA: mixed crop-livestock and mixed crop farming systems. Also, this review revealed that most nutrient balance studies in SSA have been done in mixed crop and livestock farming systems. However, regardless of the farming systems, the overall mean nutrient balances in all studies, particularly those of nitrogen (N) and potassium (K), were negative, indicating significant nutrient mining. The review further revealed a vast range of biophysical soil fertility management technologies; however, their adoption has been limited by socio-economic aspects including land ownership, gender, financial position, literacy level, and access to inputs. Therefore, in view of this situation, integrating biophysical and socioeconomic disciplines could address the problem of soil nutrient depletion holistically, thus decreasing the existing negative nutrient balances in the SSA region.

A Review on Challenges and Opportunities in Management of Soils of Arid and Semi-Arid Regions of Kenya

Arid and semi-arid lands occupy currently 88% of arable land mass in Kenya, a region with significant diversity of production systems and economic opportunities. However, these areas are characterised by low and erratic rainfall, hence challenges to agriculture and socioeconomic development in the wake of an increasing population and the impacts of climate change. This review seeks to identify key challenges and opportunities associated with the management of agricultural soils in these arid and semi-arid communities. Arid and semi-arid regions in Kenya are dominated by 10 soil types; Solanchaks, Solonetz, Cambisols, Arenosols, Leptosols, Vertisols, Fluvisols, Phoezems, Calcisols, and Gypsisols. Among the main soil fertility challenges in these soils are moisture stress, high erodibility, and low organic matter content, salinity, and sodium toxicity, the deficiencies of mainly N, P, Zn, and Fe, hence the vulnerability of over 14 million inhabitants to the shocks of low crop and pasture production. Moreover, the adoption of soil conservation practices remains low as existing soil fertility management technologies have been criticized for being too abstract and not providing context and site-specific solutions. Improving soil fertility and moisture levels enhances soil ecosystem functions and food and pasture production in these regions. Encouraging farmers to join soil and water conservation groups, while providing economic incentives, could potentially accelerate the adoption of soil and water practices at the farm level through pulling resources together. Future research to validate a site and context-specific integrated soil fertility improvement technologies for these soils is evitable to enhance soil functions, agricultural production and livelihood at house hold level.

Exploring adoption effects of subsidies and soil fertility management in Malawi

AbstractFarm input subsidies and integrated soil fertility management (ISFM) technologies are popular policy interventions in sub‐Saharan Africa, often with the stated goals of increasing crop yields and incomes while reducing hunger and poverty. However, little is known about the combined adoption effects of input subsidies and ISFM technologies on farm productivity and household nutrition in developing countries. Using a decade of nationally representative panel data from Malawi, we analyse joint adoption effects of input subsidies and ISFM technologies on smallholder household welfare. We use multivariate probit, dynamic random effects probit, and multinomial endogenous treatment effects models to account for selection bias and endogeneity originating from both observed and unobserved heterogeneity. We find that participation in a farm input subsidy programme is strongly associated with a 15–29 percentage point increase in the probabilities of adoption of three ISFM technologies: conservation agriculture, soil and water conservation, and organic fertiliser. Furthermore, we find that the joint use of input subsidies and ISFM technologies increased crop income and micronutrient consumption by at least 12%. Our findings suggest that the joint use of input subsidies and ISFM technologies are among potential strategies to address low productivity and nutritional insecurity through improvements in soil health.

Profitability of Gliricidia-Maize System in Selected Dryland Areas of Dodoma Region, Tanzania

Declining soil fertility and climatic extremes are among major problems for agricultural production in most dryland agro-ecologies of sub-Saharan Africa. In response, the agroforestry technology intercropping of Gliricidia (Gliricidia sepium (Jacq.)) and Maize (Zea mays L.) was developed to complement conventional soil fertility management technologies. However, diversified information on the profitability of Gliricidia-Maize intercropping system in dryland areas is scanty. Using data from the Gliricidia and maize models of the Next Generation version of the Agriculture Production Systems sIMulator (APSIM), this study estimates the profitability of the Gliricidia-Maize system relative to an unfertilized sole maize system. Results show significant heterogeneity in profitability indicators both in absolute and relative economic terms. Aggregated over a 20-year cycle, Gliricidia-Maize intercropping exhibited a higher Net Present Value (NPV = Tsh 19,238,798.43) and Benefit Cost Ratio (BCR = 4.27) than the unfertilized sole maize system. The NPV and BCR of the latter were Tsh 10,934,669.90 and 3.59, respectively. Moreover, the returns to labour per person day in the Gliricidia-Maize system was 1.5 times those of the unfertilized sole maize system. Sensitivity analysis revealed that the profitability of the Gliricidia-Maize system is more negatively affected by the decrease in output prices than the increase in input prices. A 30% decrease in the former leads to a decrease in NPV and BCR by 38% and 30%, respectively. Despite the higher initial costs of the agroforestry establishment, the 30% increase in input prices affects more disproportionally unfertilized sole maize than the Gliricidia-Maize system in absolute economic terms, i.e., 11.1% versus 8.8% decrease in NPV. In relative economic terms, an equal magnitude of change in input prices exerts the same effect on the unfertilized sole maize and the Gliricidia-maize systems. This result implies that the monetary benefits accrued after the first year of agroforestry establishment offset the initial investment costs. The Gliricidia-Maize intercropping technology therefore is profitable with time, and it can contribute to increased household income and food security. Helping farmers to overcome initial investment costs and manage agroforestry technologies well to generate additional benefits is critical for the successful scaling of the Gliricidia-Maize intercropping technology in dryland areas of Dodoma, Tanzania.

Farm factors influencing soil fertility management patterns in Upper Eastern Kenya

Farmer adoption of soil technologies has been commonly explored in the literature using binary models, which significantly simplifies the multi-dimensional nature of soil technology adoption. Therefore, it is necessary to fill this gap to improve technology adoption models to enhance small-scale farmers' soil fertility management practices. We investigated patterns of multiple soil technology adoption using multivariate analysis and regression modeling in Central Kenya. We used a cross-sectional survey design to sample 300 small-scale farmers in Tharaka-Nithi County and employed a multi-stage sampling design. We found that soil nutrient applications and soil fertility management patterns were linked to crop enterprises, driven by socioeconomic farm characteristics. Our findings showed that farmers applied higher N inputs and soil fertility management technologies on crops with high economic and staple use-values. Farmers in high potential agro-ecozones and those with higher incomes and TLU (Tropical Livestock Units) intensity applied higher fertilizer N intensities than farmers in low-potential zones, with lower incomes and lesser TLU intensities. Farm size was inversely related to nitrogen application intensity, while farmers had a lower propensity to restore fields undergoing degradation. We obtained five significant sets of soil fertility management technologies that farmers practiced due to the complementary nature of their benefits. We found that farmer perceptions of soil fertility, income distribution, site, education qualifications, credit access, labor availability, and access to extension services influenced their technology adoption patterns. We recommend that farmer sensitization about the fertility of their soils is needed to enhance soil fertility management strategies in small-scale farming systems.

Uptake of integrated soil fertility management technologies in heterogeneous smallholder farms in sub-humid tropics

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.

Tillage system and integrated soil fertility inputs improve smallholder farmers’ soil fertility and maize productivity in the Central Highlands of Kenya

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.

Economic evaluation and socioeconomic drivers influencing farmers’ perceptions on benefits of using organic inputs technologies in Upper Eastern Kenya

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.

The influence of organic and inorganic nutrient inputs on soil organic carbon functional groups content and maize yields

Locally available organic inputs to soil, solely or in combination with inorganic fertilizers, are used to reverse declining soil fertility and improve soil organic matter content (SOM) in smallholder farms of most Sub-Saharan Africa (SSA) countries. Soil organic matter characterization can indicate soil organic input, carbon (C) sequestration potential, or even an authentication tool for soil C dynamics in C stocks accounting. This study determined the effects of the long-term application of selected integrated soil fertility management (ISFM) technologies on SOM functional group composition and maize yields. The study was carried out on an ongoing long-term soil fertility field experiment established in 2004 in Mbeere South sub-county, the drier part of upper Eastern Kenya. The experimental design was a randomized complete block design. The ISFM treatments were 60 kg ha−1 nitrogen (N) from goat manure (GM60); 30 kg ha−1 inorganic N fertilizer (IF30); 60 kg ha−1 inorganic N fertilizer (IF60); GM30+IF30; 90 kg ha−1 inorganic N fertilizer (IF90); 60 kg ha−1 N from lantana (Lantana camara) (LC60); LC30+IF30; 60 kg ha−1 N from mucuna beans (Mucuna pruriens) (MP60); MP30+IF30; 60 kg ha−1 N from Mexican sunflower (Tithonia diversifolia) (TD60); TD30+IF30, and a control with no inputs. The C compositions of ground soil samples and organic amendments were analyzed using 13C solid-state NMR. The GM60, GM30+IF30, LC60, and TD60 treatments had much higher Alkyl and O-Alkyl C SOM functional groups than the control and other treatments. The average soil C for the control was 7.47 mg kg−1 and ranged from 5.03 to 7.37, 9.57 to 18.77, and 7.03–14.50 mg kg−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The mean grain yield for the control was 0.56 Mg ha−1 and ranged from 1.51 to 1.99, 1.94 to 4.16, and 2.98–4.60 Mg ha−1 for inorganic fertilizers, organic fertilizers, and organic + inorganic fertilizers, respectively. The results showed that a long-term application of sole organic fertilizers or combined with inorganic fertilizers increases maize yield and soil C sequestration potential. The increase was attributed to high Alkyl and O-Alkyl C SOM functional groups. Hence, knowing the C fraction content of organic inputs is vital in determining the best-fit management technologies for ameliorating soil fertility and sustaining and/or improving crop yields.

Factors influencing adoption of integrated soil fertility management technologies by smallholder farmers in Ghana

This study examines smallholder farmers’ adoption of both a full set of and multiple bundles of integrated soil fertility management technologies, and estimates the determinants of and assesses the relationship among adoption practices using the logistic model and multivariate probit model respectively. A cross-sectional survey was used to collect data from 300 smallholder farmers who benefitted from a sustainable food security and environmental health project in three districts in Ghana. Four ISFM technologies (zero or minimal tillage, inorganic fertilizer, leguminous crop, and crop rotation) serve as outcome variables. The result revealed that only 26.7% of the respondents adopted the full set of the ISFM technologies. Agroecological zone, a spatial variable has been found to significantly influence smallholder farmers adoption of the full ISFM technologies. One or more of the predictor variables, purpose of farming, land ownership, distance from house to the nearest input shop, access credit and agroecological zone, have been found to significantly influence the adoption of the multiple ISFM technologies. However, the computed correlation coefficients of the independent determinants show inconsistent significant values. The implication of this finding is that the adoption of multiple ISFM technologies cannot be estimated utilizing common determinants. Therefore, extension service in the region should focus on crucial factors that influence adoption of specific multiple ISFM technologies to maximize adoption options.

Modelling smallholder farmers' preferences for soil fertility management technologies in Benin: A stated preference approach.

The decline of soil fertility is a major constraint which results in lower levels of crop productivity, agricultural development and food security in Sub-Saharan Africa. This study is the first to perform a focalized investigation on the most interesting technological profiles to offer to each category of producers in Benin agricultural development hubs (ADHs) using the stated preference method, more precisely, the improved choice experiment method. The investigation focused on 1047 sampled plots from 962 randomly selected producers in villages of the Smallholder Agricultural Productivity Enhancement Program in Sub-Saharan Africa of the ADHs. An analysis of the experimental choice data with the endogenous attribute attendance and the latent class models was carried out to account for the attribute non-attendance phenomenon and the heterogeneity of the producers' preferences. However, three classes of producer with different socio-economic, demographic, and soil physicochemical characteristics were identified. Thus, the heterogeneity of preferences was correlated with the attributes linked to the cost, sustainability, and frequency of plot maintenance. All producers, regardless of the ADHs, had a strong attachment to accessibility of technologies with short time restoration of soil fertility, and the ability to obtain additional benefits. These latest attributes, added to that relating to cost, tended to have a low probability of rejection in the decision-making process. These results have implications for local decision-makers facing the complex problem of resolving land degradation and local economic development challenges. The generalizability of these findings provides useful insight and direction for future studies in Sub-Saharan Africa.

Comparison between observed and DeNitrification-DeComposition model-based nitrous oxide fluxes and maize yields under selected soil fertility management technologies in Kenya

Process-based biogeochemical models can be used to simulate soil nitrous oxide (N2O) fluxes and maize yields and draw insights on yields improvement and climate change mitigation options. We compared both observed and DeNitrification-DeComposition (DNDC) simulated soil N2O fluxes and maize yields. We used DNDC model to simulate soil N2O fluxes and maize yields under four soil fertility treatments (inorganic fertiliser, animal manure, animal manure + inorganic fertiliser and control,) replicated thrice for 1 year in Central Highlands of Kenya. We sampled soil N2O fluxes using static chambers installed in each plot. We analysed soil N2O using gas chromatography and calculated cumulative fluxes using trapezoidal rule linear interpolation between sampling dates. DNDC showed poor results in simulating daily N2O fluxes (157.16% ≤ normalised root mean square error (nRMSE) ≤ 324.01% and 0.90 ≤ modelling efficiency (NSE) ≤ 0.96), good to excellent performance in simulating cumulative annual soil N2O fluxes (6.16 ≤ nRMSE ≤12.86 and 0.63 ≤ NSE ≤ 0.86) and good to excellent performance in simulating maize yields (1.15% ≤ nRMSE ≤13.86% and 0.51 ≤ NSE ≤ 0.88) across all soil fertility treatments. The DNDC model had good to excellent performance in simulating cumulative soil N2O fluxes and crop yields across treatments. Though the model captured yield-scaled N2O fluxes and N2O emission factors across treatments, they were underestimated under manure treatment. There is a need to continue calibrating the DNDC model for improved capture of daily N2O fluxes and uptakes on Kenyan soils.

Adoption Intensity of Selected Organic-Based Soil Fertility Management Technologies in the Central Highlands of Kenya

Soil fertility decline continues to be a major challenge limiting agricultural productivity globally. Despite the novelty of organic-based technologies in enhancing agricultural production in Kenya's central highlands, adoption is low. Therefore, we carried out a cross-sectional household survey of 300 randomly selected smallholder farmers to determine the specific organic-based practices by farmers; and the socioeconomic factors that influence the adoption intensity of selected organic-based technologies. We used descriptive statistics to summarize the data and the Tobit regression model to evaluate the socioeconomic determinants of adoption intensity of selected organic-based technologies. We identified nine organic-based technologies that had different adoption rates among the farmers. The majority of the farmers had adopted manure (97%) and manure combined with fertilizer (92%) in Murang'a and Tharaka-Nithi, respectively. Manure was applied to the largest land in Murang'a with 31% of the cultivated land. In comparison, manure combined with fertilizer had the highest adoption intensity in Tharaka-Nithi applied to about 25% of the cultivated land. Gender, age of the household head, level of education, household size, access to external labor, training, Tropical Livestock Unit, agriculture group membership, access to credit, land cultivated, and farming experience influenced the adoption intensity of organic-based technologies among smallholder farmers. Based on the smallholder farmers' adoption behavior, this study can be used to disaggregate the farming households better in order to tailor specific organic-based soil fertility technologies solutions that meet their unique needs. One group would be those households that face specific constraints, as reflected in their low adoption rates, women-headed households and older farmers, and thus require more targeted / intensive efforts to overcome these barriers. The other group would be those households that require less focus because, when confronted with the technologies, they are more likely to adopt them easily, for example, the male-headed households. Hence, the smallholder farmers' adoption behavior, can enable policymakers to form a base for designing appropriate policies that encourage the adoption of organic-based soil fertility technology by smallholder farmers.

Using the Ordered Probit Model to Predict Drivers for Adoption of Multiple Soil Fertility Management and Conservation Technologies in Potato Production Systems in Uganda

Using the Ordered Probit Model to Predict Drivers for Adoption of Multiple Soil Fertility Management and Conservation Technologies in Potato Production Systems in Uganda

Accessibility and Reliability of Information Sources in Dissemination of Soil Fertility Management in Eastern Kenya

Increased recognition of soil fertility depletion as the main factor limiting crop production in many small holder farms in sub-Saharan African has renewed interest in the dissemination of soil fertility management technologies. Despite soil technology development and research outputs, few of the recommendations from various soil fertility management research activities have been adopted by the small-scale farmers on a large-scale level. Only a small proportion of allocated research resources is invested in dissemination among research institutions. The objective of the study was to investigate communication channels used in dissemination of soil fertility management practices in Mbeere and Meru South Districts. Two hundred and forty randomly selected farmers were interviewed. Data collected was analyzed using SPSS. The study revealed that 32.5% of the farmers who used combined organic and inorganic fertilizers received information from government extension officers while 41.3% of the farmers who use animal manure utilized their own farming experience. In disseminating soil erosion control measures, 51.2% of the farmers indicated that, farmer to farmer extension was the most commonly used. Also, 33.8% mentioned demonstration as the main method used in training soil fertility management practices. In general, the most common source of information was other farmers while there was least participation of researchers and agro input dealers in dissemination of soil fertility technologies. Thus, the study recommended more participation of stakeholders other than government extension officers as well as use of combined extension methods with farmer involvement in dissemination of soil fertility management practices. Keywords: manure, extension agents, farmer to farmer extension method, demonstration DOI: 10.7176/DCS/10-11-03 Publication date: November 30 th 2020