Farmers In sub-Saharan Africa Research Articles

Tripartite interaction between Striga spp., cereals, and plant root-associated microorganisms: a review

Abstract Striga spp. is a major threat to cereal and legume production, putting the food security and economy of smallholder farmers in sub-Saharan Africa at severe risk. This is manifested in the fact that Striga spp. infestation can result in up to 90% loss of both cereal and legume production. A consensus exists that there is yet no single measure to efficiently control Striga spp. This is mainly because of the limited fundamental knowledge of the genetics and ecology of Striga spp. and its interaction with its hosts and host root-associated microorganisms, including plant growth-promoting rhizobacteria (PGPR). Since Striga spp. is a root parasite, it is speculated that PGPR play a key role in controlling the emergence and development of Striga spp. At the same time, PGPR may exhibit beneficial effects on growth promotion of the host to strengthen its tolerance against Striga spp. attacks, while on the other hand, it may also induce, similar to biocontrol agents, direct suicidal effects on Striga spp. Such hypothesized associations between Striga spp., crops (e.g., cereals such as sorghum and maize), and PGPR remain largely unknown, and the central question remains if PGPR play an important role in the Striga -crop pathosystem. This knowledge gap is the central impetus of this review. It will elaborate the complex and fascinating tripartite ecological system of cereals, Striga spp. and root-associated microorgamisms. In a first step, the review will provide a comprehensive summary of the pairwise interactions between Striga spp. and cereals, cereals and PGPR, as well as Striga spp. and PGPR. This summary will then merge into the discussion about the yet limited knowledge of the tripartite interaction between cereals, Striga spp., and PGPR. This specifically includes the exploration of recent discoveries related to population genetics and the life cycle of Striga spp, host (cereal) defense responses to and mechanisms of Striga spp. infestation, as well as the inhibitory and stimulatory role of PGPR on Striga spp. seed germination. In a concluding section, remaining research gaps are identified and necessary research perspectives are provided to direct prospective research toward further understanding the relationship between the three biological components paving the avenue to develop biological and environmentally friendly measures to fight off the everlasting threat of Striga spp.

Agronomic and morphological diversity of Bambara groundnut (Vigna subterranea (L.) Verdc.) accessions in North-Central Namibia

Bambara groundnut (Vigna subterranea (L) Verdc.) is an orphan, underutilised and less exploited crop in Africa and beyond, yet it is an essential traditional crop for subsistence farmers in sub-Saharan Africa. Currently, in Namibia, neither a pre-breeding nor a breeding programme exists for Bambara groundnut. Twenty-five Bambara groundnut accessions acquired locally and outside Namibia were characterised for descriptor state, including possible character diversity on the quantitative descriptors. Square lattice design with three replications was used. Data were analysed using analysis of variance (ANOVA), Pearson correlation moment, Principal Component Analysis (PCA), and cluster analysis. ANOVA indicated significant differences (P < 0.05) among accessions for most of the characters measured, and highly significant differences (P < 0.01) for the number of pods per plant, pod yield, seed yield, plant height, and dry biomass. The dendrogram sub-criterion indicated three clusters, confirming the results of the PCA, which grouped accessions with common descriptors in the same quadrants. PCA biplot showed that the first two components explained 59.55% of the variation. Overall results suggest that the Bambara groundnut accessions evaluated in this study showed high variability, thus can be used as a source of pre-breeding materials to initiate a national breeding programme.

Selecting for Coupling Phase Recombination between Potyvirus Resitance and White Endosperm Colour in Maize Preferred by Farmers in Sub-Saharan Africa (SSA)


 
 
 Maize lethal necrosis (MLN) disease caused by a combined infection of Maize chlorotic mottle virus (MCMV) and any cereal infecting potyvirus is a threat to food security in Sub-Saharan Africa (SSA). Resistance to potyvirus has been extensively studied and Mdm1 gene for potyvirus resistance on chromosome 6 of maize is linked to Y1 gene for maize endosperm colour. This study is aimed at se- lecting for coupling-phase recombination of potyvirus resistance and white endosperm colour. White susceptible maize lines CML333 and CML277 were crossed with a yellow resistant line, Pa405, to produce F1 and F2 progenies. Progenies were screened using molecular markers to recover 22 white endosperm recombinants. 22 selections were advanced to F3 recombinant families, and 10 were as- sayed for their responses to Maize dwarf mosaic virus (MDMV) and Sugarcane mosaic virus (SCMV). Four families segregated for SCMV resistance, selection of homozygous recombinants within these families will provide lines appropriate for improving lines with resistance to SCMV and MLN resistance in SSA.
 KEY WORDS: MAIZE LETHAL NECROSIS (MLN), WHITE MAIZE, POTYVIRUS RESISTANCE, GENETIC RECOMBINATION, SUB-SAHARAN AFRICA.
 
 

Mulching is the most important of the three conservation agriculture principles in increasing crop yield in the short term, under sub humid tropical conditions in Zimbabwe

Some smallholder farmers in Sub Saharan Africa (SSA) have failed to adopt all the three principles of conservation agriculture (CA) because of various reasons including lack of alternative weed management methods (soil tillage), crop-livestock interactions (crop residue mulch used as livestock feed) and poorly developed markets for other crops (diversified cropping system). Studies have shown that smallholder farmers incorporate one or two CA principles, not all three, at a time in their cropping systems. Our study sought to disaggregate the effects of the three CA principles on crop growth with or without mineral fertilizer in order to determine which principle or combination of principles resulted in highest yield increase in the short to medium term. The research was conducted over four cropping seasons at Hunyani Farm located in Zvimba district in north western Zimbabwe characterized by sub humid tropical conditions and fine sandy loam soils. A split-split-plot design, with tillage as the main plot, mulch as the sub plot, rotation as the sub-sub plot and fertility regime as the treatments was used. Fertility treatments were control (no fertilizer added) and 120 kg N ha−1+ 30 kg P ha-1 +15 kg K ha−1 mineral fertilizer and the experiment was replicated three times. Reduced tillage increased maize grain yield from the third season when compared with mouldboard ploughing. The positive effects of mulching were higher when fertilizer was applied (>90 %) compared with no fertilizer application. Crop rotation (maize-soybean) had no significant effects on grain and aboveground dry matter yield. The benefits of the three CA principles on crop yield followed the order mulch > reduced tillage > crop rotation. The combined effects of the three CA principles on maize grain yield were higher than conventional tillage and any other one or two principles together indicating the importance of integrating the three principles for best results.

Contract Farming in Sub-Saharan Africa: An Empirical Review

Contract farming may be defined as agricultural production carried out according to a prior agreement in which the farmer commits to producing a given product in a given manner and the buyer commits to purchasing it. Proponents of contract farming argue that it links small-scale farmers to lucrative markets and solves a number of problems small-scale farmers face in diversifying into high-value commodities. Opponents argue that the imbalance in power between the buyer and the farmer leads to an agreement unfavorable to the farmer. A large majority of empirical studies suggest that contract farming schemes raise the income of farmers participating in the schemes. Contract farming schemes typically face a number of challenges that limit their ability to deliver inputs, credit, and technical assistance to small-scale farmers like side-selling, unwillingness of the company to pay the negotiated price and use quality standard to evade their commitments and high cost of working with large numbers of small-scale farmers. So, government policy should be to facilitate the development of contract farming schemes and developing countries can also promote pro-poor contract farming by creating a conducive policy environment. Keywords : Contract Farming, Small- Scale, Farmers, Sub - Saharan Africa DOI : 10.7176/DCS/9-12-01 Publication date: December 31 st 2019

Improving sorghum productivity under changing climatic conditions: A modelling approach

Climate variability and change will have far reaching consequences for smallholder farmers in sub-Saharan Africa, the majority of whom depend on agriculture for their livelihoods. Crop modelling can help inform the improvement of agricultural productivity under future climate. This study applies the Agricultural Production Systems sIMulator (APSIM) to assessing the impacts of projected climate change on two (early and medium maturing) sorghum varieties under different management practices. Results show high model accuracy with excellent agreement between simulated and observed values for crop phenology and leaf number per plant. The prediction of grain yield and total biomass of an early maturing variety was fair RMSEn (22.9 and 23.1%), while that of the medium maturing was highly accurate RMSEn (14.9 and 11.9%). Sensitivity analysis performed by changing the calibrated variables of key plant traits in the model, showed higher significant yield change by + or - 10 % changed in radiation use efficiency, (RUE), coefficient extinction (Coeff_ext) and Phyllocron (Phyllo) for early maturing variety while + or - 10 % changed in phyllochron and RUE showed a significant yield change for the medium maturing variety. Under climate change scenerios using RCP 8.5, the simulated yield for the early–maturing variety revealed high inter-annual variability and potential yield loss of 3.3% at Bamako and 1% at Kano in the near-future (2010–2039) compared to baseline (1980–2009). The mid-century (2040–2069) projected yield decline by 4.8% at Bamako and 6.2% at Kano compared to baseline (1980–2009). On the contrary, the medium maturing variety indicated significantly yield gain with high yielding potential in both climate regimes compared to the baseline period (1980–2009). The simulated grain yield increased by 7.2% at Bamako and 4.6% at Kano, in the near-future (2010–2039) while in the mid-century (2040–2069) projected yield increase of 12.3% and 2% at Bamako and Kano compared to baseline (1980–2009). Adaptation strategies under climate change for varying sowing dates in the near-future (2010–2039, indicated that June sowing had a higher positive yield gained over July and August sowing for early maturing variety; July sowing simulated positive gained by 5 -11% over June and August sowing for medium maturing variety in both locations. Similarly, under the mid-century (2040–2069), among the sowing dates and in both locations, June sowing indicates lowest negative yield change over July and August sowing for early maturing variety. However, for medium maturing variety, July sowing had the highest yield gain of 16% over June and August sowing at Bamako and June highest positive yield gained of 11.4% over July and August at Kano. Our study has, therefore, demonstrated the capacity of APSIM model as a tool for testing management, plant traits practices and adoption of improved variety for enhancing the adaptive capacity of smallholder farmers under climate change in the Sudanian zone of West Africa. This approach offers a promising option to design more resilient and productive farming systems for West Africa using the diverse sorghum germplasm available in the region.

Micro-livestock in smallholder farming systems: the role, challenges and opportunities for cavies in South Kivu, eastern DR Congo

Livestock play multiple roles for smallholder farmers in sub-Saharan Africa. Mixed crop-livestock systems are common in South Kivu, eastern DR Congo, but herd sizes are small and numbers of large livestock (i.e. cattle) have declined, due to high population density, recent conflicts and extreme poverty. Over half of the farmers keep cavies, a type of micro-livestock fitting the circumstances of smallholders and a valuable asset especially for the poorest households. To characterize cavy husbandry practices, detailed monthly on-farm data on cavy numbers, weights, herd dynamics and feeding practices were collected over 15 months and from households in two contrasting sites in South Kivu. Cavy herds contained on average 10 animals and strongly varied in size over time and between households. The main reasons for keeping cavies were meat consumption, especially for children, and the opportunity to generate petty cash. A large difference was observed in adult cavy live weights between the sites (an average of 0.6 and 1.0 kg per animal in Kabamba and Lurhala, respectively) and attributed to differences in cavy husbandry and genetics. In both sites, quantities of fresh fodder on offer were larger than fodder demand by 50–100%, but no correlation was found between amount of fodder on offer and cavy weight. Farmers faced several constraints to cavy production, including substantial declines in cavy herd size due to predation or theft and a lack of knowledge regarding breeding and feeding. Hence, the introduction of cages to limit mortality and fodder cultivation to improve feed quality were opportunities for improving cavy production. Overall, micro-livestock present a promising entry-point for development initiatives, also outside DR Congo, because of their potential to decrease poverty and improve human nutrition.

Machine learning models for predicting the use of different animal breeding services in smallholder dairy farms in Sub-Saharan Africa

This study is concerned with developing predictive models using machine learning techniques to be used in identifying factors that influence farmers' decisions, predict farmers' decisions, and forecast farmers' demands relating to breeding service. The data used to develop the models comes from a survey of small-scale dairy farmers from Tanzania (n = 3500 farmers), Kenya (n = 6190 farmers), Ethiopia (n = 4920 farmers), and Uganda (n = 5390 farmers) and more than 120 variables were identified to influence breeding decisions. Feature engineering process was used to reduce the number of variables to a practical level and to identify the most influential ones. Three algorithms were used for feature selection, namely: logistic regression, random forest, and Boruta. Subsequently, six predictive models, using features selected by feature selection method, were tested for each country-neural network, logistic regression, K-nearest neighbor, decision tree, random forest, and Gaussian mixture model. A combination of decision tree and random forest algorithms was used to develop the final models. Each country model showed high predictive power (up to 93%) and are ready for practical use. The use of ML techniques assisted in identifying the key factors that influence the adoption of breeding method that can be taken and prioritized to improve the dairy sector among countries. Moreover, it provided various alternatives for policymakers to compare the consequences of different courses of action which can assist in determining which alternative at any particular choice point had a high probability to succeed, given the information and alternatives pertinent to the breeding decision. Also, through the use of ML, results to the identification of different clusters of farmers, who were classified based on their farm, and farmers' characteristics, i.e., farm location, feeding system, animal husbandry practices, etc. This information had significant value to decision-makers in finding the appropriate intervention for a particular cluster of farmers. In the future, such predictive models will assist decision-makers in planning and managing resources by allocating breeding services and capabilities where they would be most in demand.

Multi-influencing-factors’ evaluation for organic-based soil fertility technologies out-scaling in Upper Tana Catchment in Kenya

Low adoption of soil fertility technologies, partially attributed to low technology out-scaling initiatives, is a critical hindrance to agricultural productivity enhancement of most smallholder farms in sub-Saharan Africa. Application of geospatial tools for spatial suitability evaluation of soil fertility management technologies can be a breakthrough in their promotion and out-scaling existing novel technological initiatives. The study objective was to develop a data-driven multi-influencing-factor (MIF) geospatial approach for out-scaling organic-resource based soil fertility management technologies. Using the developed geospatial approach, we delineated suitable zones for targeted out-scaling of organic resource technologies in the Upper Tana River (UTC) catchment in Kenya. We acquired multiple datasets from different sources and used them to prepare thematic layers. The factors used included rainfall, elevation, cattle density, bulk density, slope, soil pH, soil organic carbon, cation exchange capacity, drainage, and soil texture. The input layers were georeferenced, converted to raster formats, standardized to a range of 1 to 5, after which we generated the suitability map through a weighted overlay technique. The delineated suitability map showed that about 0.002% of UTR was least suitable, 4.7% marginally suitable, 38.5% moderately suitable, 34.7% medium-high suitable while 0.03% was highly suitable for organic resources out-scaling The results obtained indicate the potential of the geospatial approach as a scaling out methodology for organic-based soil fertility technologies. The suitability delineation established that Nyeri, Murang'a and Meru are the most suitable areas for the use of most organic resources in the Upper Tana catchment of the Central Highlands of Kenya. The suitability maps can inform policymakers, planners, and decision-makers in identifying the suitable sites for the use of organic-based soil fertility resources. Based on this study, we recommend the use of the developed a data-driven multi-influencing-factor (MIF) geospatial approach in the scaling out of the organic-based soil fertility technologies, not only in the study area but also other regions in sub-Saharan Africa.

Productivity of intercropping with maize and common bean over five cropping seasons on smallholder farms of Tanzania

Abstract Intercropping with maize (Zea mays L.) and common bean (Phaseolus vulgaris L.) is one of the widely used practices of producing food crops on smallholder farms in Sub-Saharan Africa (SSA). However, the knowledge on the options toward intensification of available practices in order to optimize systems productivity using intercrops is generally lacking. Therefore, this study evaluated the effects of intercropping, cropping seasons, and different varieties of common bean on productivity of the maize-common bean based intercrop through 5 cropping seasons from 2015 to 2017. Experimental site is located at 03°18 ′03.74′' S and 37°12′13.94′ E and an altitude of 956 m above sea level in the northern highlands of Tanzania. Hybrid maize Dekalb brand (DK 8031) and two varieties of common bean (improved Lyamungu 90 and local Mkanamna) were used. The treatments within a replicate were: (1) sole crops: (i) maize, (ii) local bean, (iii) improved bean, and (2) intercrops: (i) maize + local bean, (ii) maize + improved bean. Interaction and individual effects of cropping seasons (S) (periods of years – short and long rains), varieties of common bean (V), and cropping systems (C) (sole and intercrop) were studied. Results indicated that S × V interaction was significant on bean grain yield and 100-seed weight. Improved bean outweighed the local bean with grain yields ranging from 2.2–3.5 t ha-1 and 0.2–2.5 t ha-1, respectively. The effect of S was significant on all measured variables in beans and the effect of M was only significant on total biomass. Further, S significantly affected all measured variables in maize and grain yields ranged from 2.3–2.6 t ha-1. In maize, correlations were strong (r = 0.48*; P = 0.0325) between maize grain yield and ground coverage of leaf canopy measured 42–56 days after sowing. The land equivalent ratios (LERs) for maize intercropped with improved and local beans were 1.48 and 1.55, respectively but LER values did not differ significantly between bean varieties. In this study, both common bean varieties were sown simultaneously with the maize, which might have resulted in their differential performance. It is recommended that studies are conducted to evaluate time of introducing this legume crop to a maize system such as early sowing, sowing mid in the season after a maize crop is well established, and sowing late in the season when the leaves in maize plant have started to senesce.

The Dynamics of Climate Change Adaptation in Sub-Saharan Africa: A Review of Climate-Smart Agriculture among Small-Scale Farmers

Climate-smart agriculture (CSA) as a credible alternative to tackle food insecurity under the changing climate is gaining wide acceptance. However, many developing countries have realized that concepts that have been recommended as solutions to existing problems are not suitable in their contexts. This paper synthesizes a subset of literature on CSA in the context of small-scale agriculture in sub-Saharan Africa as it relates to the need for CSA, factors influencing CSA adoption, and the challenges involved in understanding and scaling up CSA. Findings from the literature reveal that age, farm size, the nature of farming, and access to extension services influence CSA adoption. Many investments in climate adaptation projects have found little success because of the sole focus on the technology-oriented approach whereby innovations are transferred to farmers whose understanding of the local farming circumstances are limited. Climate-smart agriculture faces the additional challenge of a questionable conceptual understanding among policymakers as well as financing bottlenecks. This paper argues that the prospects of CSA in small-scale agriculture rest on a thorough socio-economic analysis that recognizes the heterogeneity of the small farmer environment and the identification and harnessing of the capacities of farming households for its adoption and implementation.

Role of Local Policies in Facilitating Adaptation of Smallholder Farming to Climate Change in Uganda

The research was funded by a USAID project entitled ‘Enhancing Climate Resilience of Agricultural Livelihoods’ that was implemented by the International Institute of Tropical Agriculture (IITA in partnership with Makerere University Centre for Climate Research and Innovation (MUCCRI) and the National Agriculture Research Organization (NARO). The CGIAR program on Climate Change, Agriculture and Food Security (CCAFS) provided additional support. Abstract Smallholder farming in Sub-Saharan Africa is highly vulnerable to the impacts of climate change and supportive local policies and plans are needed guide climate resilient farming systems. This study explores how local policies are enabling adaptation of smallholder farming to the impacts of climate change in Uganda. A mixed methods approach was used including review of policies and other literature, field assessments conducted Eastern and Central regions of Uganda. Data was collected from smallholder farmers, government officials and non-state actors at district, sub-county and village levels. Findings reveal that whereas Uganda has an elaborate national climate change policy framework that prioritizes the mainstreaming of climate change in policies and practices at all levels of government, development policies and plans at the local levels have not yet adequately incorporated climate change, and the adaptation practices adopted by smallholder farmers to address the negative impacts of climate change are more reactionary, and are not guided or influenced by local adaptation policies. Effective local adaptation policy and practice is constrained by non-inclusive policy formulation processes, institutional and human resource gaps, climate finance and unreliable climate information and advisory services. We suggest the strengthening local adaptive capacity through inclusive local adaptation policy formulation and implementation, improved climate information services and strong local institutional framework to support smallholder farmers build resilience to climate change. Keywords: climate risks, vulnerability, local adaption policies, resilient agriculture, Uganda DOI : 10.7176/JEES/9-11-09 Publication date: November 30 th 2019

Can shallow groundwater sustain small-scale irrigated agriculture in sub-Saharan Africa? Evidence from N-W Ethiopia

We present an evidence-based approach to identify how best to support development of groundwater for small-scale irrigation in sub-Saharan Africa (SSA). We argue that it is important to focus this effort on shallow groundwater resources. We demonstrate and test this proposal at a case study site: Dangila woreda in the north-western highlands of Ethiopia. This site was selected to allow exploration of a shallow weathered volcanic regolith type aquifer formation which is found to the South of Lake Tana and also exists more extensively across Ethiopia. We believe lessons from this case study are transferable and there is a case for arguing that shallow groundwater represents a neglected opportunity for promoting sustainable small-scale irrigated agriculture in SSA.In comparison with other global regions, the groundwater resources of SSA are among the least understood; borehole records and hydrogeological studies are lacking. Assessments of groundwater resources do exist, but they rely on remotely sensed data combined with modelling at national or regional scale, and they focus on deeper aquifers. There is a need for these broad evaluations to be supplemented by localised and detailed assessments. The case study here presents such an assessment in order to support analysis of strengths, weaknesses, opportunities and threats associated with developing small-scale irrigation utilising shallow groundwater.A multimethod groundwater recharge assessment was conducted utilising formal and community-based monitoring, field investigation and existing published data. Water table recovery tests at existing hand dug wells confirm that well yields of 1 l/s are achievable at the end of the wet season when water would be available to support an additional irrigated crop. Hydraulic conductivity estimates ranged from 0.2 to 6.4 m/d in the dry season and from 2.8 to 22.3 m/day in the wet season. Specific yield estimations have a wider range though the mean value of 0.09 is as would be expected.Records of groundwater levels and rainfall monitored by the local community for the period April 2014 to April 2018 show that all the wells maintained useable water levels beyond the end of the rainy season. An assessment of the hydrology of the Kilti catchment provided insights into groundwater availability within the wider area. The catchment receives about 1600 mm/year of rainfall, of which about 350 mm/year enters the groundwater as recharge, discharging to the river as baseflow with a similar amount of rapid runoff contributing to a total river flow of about 400 mm/year. The lowest value of baseflow is 82% of the mean baseflow, which suggests a degree of buffering and indicates that groundwater is available even in a very dry year.We conclude that arguments previously put forward against the promotion of shallow groundwater use for agriculture in SSA appear exaggerated. Our analysis challenges the view that shallow aquifers are unproductive and that irrigation will have unacceptable impacts on wetlands and other groundwater-dependent ecosystems. We believe lessons from this case study are transferable, and there is a case for arguing that shallow groundwater represents a neglected opportunity for promoting sustainable small-scale irrigated agriculture in sub-Saharan Africa. It appears that factors other than the physical availability of groundwater control the ‘triggering’ of development. Interventions to promote development of groundwater resources should recognise the importance of shallow aquifers.

A national atlas of tsetse and African animal trypanosomosis in Mali

BackgroundTsetse-transmitted trypanosomosis is a deadly, neglected tropical disease and a major challenge for mixed crop-livestock agriculture in sub-Saharan Africa. It is caused by several species of the genus Trypanosoma. Information on the occurrence of tsetse flies and African animal trypanosomosis (AAT) is available for different areas of Mali. However, these data have never been harmonized and centralized, which prevents the development of comprehensive epidemiological maps and constrains an evidence-based planning of control actions. To address this challenge, we created a dynamic geo-spatial database of tsetse and AAT distribution in Mali.MethodsA digital repository containing epidemiological data collected between 2000 and 2018 was assembled. In addition to scientific publications, the repository includes field datasheets, technical reports and other grey literature. The data were verified, harmonized, georeferenced and integrated into a single spatially-explicit database.ResultsFor the tsetse component, approximately 19,000 trapping records, corresponding to 6000 distinct trapping locations and 38,000 flies were included in the database. Glossina palpalis gambiensis was the most widespread and abundant species, and it was found in the southern, southern-central and western parts of the country. Glossina tachinoides was only found in the South. Only a few specimens of Glossina morsitans submorsitans were detected. For the AAT component, approximately 1000 survey records were included, corresponding to 450 distinct survey sites and 37,000 tested bovines. AAT was found in all surveyed regions, although data for the tsetse-free North and North-East are lacking. Trypanosoma vivax and Trypanosoma congolense were the dominant species, while Trypanosoma brucei infections were much less numerous.ConclusionsThe atlas of tsetse and AAT in Mali provides a synoptic view of the vector and disease situation at the national level. Still, major geographical gaps affect the North, the North-East and the West, and there is also a severe lack of data over the past five years. Trypanosomosis remains a major animal health problem in Mali. However, despite its prevalence and distribution, monitoring and control activities are presently very limited. Efforts should be made to strengthen the progressive control of AAT in Mali, and the atlas provides a new tool to identify priority areas for intervention.

An Empirically Derived Conceptual Framework to Assess Dis-Adoption of Conservation Agriculture: Multiple Drivers and Institutional Deficiencies

Efforts of national governments and international agencies aimed at alleviating hunger and poverty are often undermined by lack of long-term adoption of agricultural innovations. Studies commonly explain farmers’ adoption decisions using household general determinants, yet decision-making, particularly for under-resourced smallholder farmers in sub-Saharan Africa, is a complex process. Using the case of conservation agriculture [CA], this article analyses dis-adoption of agricultural technologies by examining multiple domains of Malawi’s CA innovation system and how these influence farmer decision-making. It analyses institutional arrangements of CA promoters, national policies and farmers’ experiences. From this, we empirically derive a multifaceted dis-adoption drivers’ framework to explain CA dis-adoption in smallholder farming systems. Our findings reveal that adverse features in national policies, institutional arrangements, technological attributes and social cultural dimensions all lead to unfavourable experiences of CA for smallholder farmers, which can culminate in dis-adoption. The CA dis-adoption drivers’ framework we develop in this study provides a useful troubleshooting tool. It can be used to guide improvements in the design and implementation of project-based interventions seeking long-term adoption of agricultural innovations across sub-Saharan Africa.

Pyrolysis of Wood Residues in a Cylindrical Batch Reactor: Effect of Operating Parameters on the Quality and Yield of Products

Appropriate technology for conversion of waste biomass into valuable products has often been overlooked in Sub-Saharan Africa. The influence of operating parameters such as; type of technology, and biomass type, on the conversion process, is a barely known. This contribution aimed at studying the pyrolysis of wood residues and the specific objectives included; (1) characterization of the organic products (wood vinegar and tar) of pyrolysis of wood residues, (2) investigation of the effect of temperature and feedstock type on the yield of products and (3) to carry out an energy balance of the pyrolysis reactor system. Wood residues were pyrolysed in a cylindrical batch reactor at temperatures 300-350, 400-450 and 500-5500C and the organic were characterised using a gas chromatograph (GC) fitted with a flame ionisation detector (FID). The most notable compounds in the wood vinegar and tar were; alcohols, acids, furans, phenols, aldehydes, and ketones. The yield of vinegar, tar and char reduced significantly with increase in temperature and the maximums were produced at 300-3500C whereas the yield of non-condensable gases increased with increase in temperature. The type of feedstock used had no significant effect on the yield and distribution of products. The energy balance of the system revealed that the process was 78% efficient. The presence of the oxygenated aliphatic and aromatic hydrocarbons makes the wood vinegar and tar potential sources of chemicals and engine fuels. Preliminary trials with wood vinegar were lethal to black ants that are predominantly a menace to farmers in Sub-Saharan Africa.

Water resource assessment, gaps, and constraints of vegetable production in Robit and Dangishta watersheds, Upper Blue Nile Basin, Ethiopia

The vast majority of farmers in sub-Saharan Africa depend on rainfed agriculture for food production and livelihood. Various factors including but not limited to rainfall variability, land degradation, and low soil fertility constrain agricultural productivity in the region. The objectives of this study were to 1) estimate the water resources potential to sustain small-scale irrigation (SSI) in Ethiopia during the dry season so as to expand food supply by growing vegetables, and 2) understand the gaps and constraints of vegetable production. The case studies were conducted in the Robit and Dangishta watersheds of the Upper Blue Nile Basin, Ethiopia. To document farmers’ cropping practices, field-level data were collected from 36 households who had been cultivating tomato (Solanum lycopersicum L.) and onion (Allium cepa L.) during the dry season (November – April). Two components of the Integrated Decision Support System (IDSS) - the Soil and Water Assessment Tool (SWAT) and Agricultural Policy Environmental eXtender (APEX) – were respectively used to assess impacts of SSI at the watershed and field-scale levels. Results suggest that there is a substantial amount of surface runoff and shallow groundwater recharge at the watershed scale. The field-scale analysis in the Robit watershed indicated that optimal tomato yield could be obtained with 500 mm of water and 200 to 250 kg/ha of urea applied with 50 kg/ha of diammonium phosphate (DAP). In Dangishta, optimum onion yield can be obtained with 400 mm of water and 120 to 180 kg/ha of urea applied with 50 kg/ha of DAP. The field-scale simulation indicated that the average shallow groundwater recharge (after accounting for other groundwater users such as household and livestock use) was not sufficient to meet tomato and onion water demand in the dry season (October to April). The field-scale analysis also indicated that soil evaporation attributed a significant proportion of evapotranspiration (60% for onion and 40% for tomato). Use of mulching or other soil and water conservation interventions could optimize irrigation water for vegetable production by reducing soil evaporation and thereby increasing water availability in the crop root zone.

Take a walk on the wild side

Climate change is expected to severely impact farming in sub-Saharan Africa. Now research shows that crop wild relatives might be able to secure Africa’s existing cropping practices by providing the genetic diversity needed to adapt crops to climates that they have never seen before.

Electronic wallet technology and the enabling environment of smallholder farmers in Nigeria

PurposeThe purpose of this paper is to critically examine the impact of a growth enhancement support scheme (GESS) on the enabling environment of smallholder farmers in sub-Saharan Africa. The main aim is to investigate the impact of the GESS on access to rural farm credit and the transport cost of smallholder farmers in the agricultural transformation agenda (ATA) in Nigeria.Design/methodology/approachThis paper adopts a survey research technique, aimed at gathering information from a representative sample of the population, as it is essentially cross-sectional, describing and interpreting the current situation. A total of 1,200 were sampled across the six geopolitical zones of Nigeria.FindingsThe results from the use of a double-hurdle model indicate that the GESS has a significant impact on farmers’ access to credit, but does not significantly impact on rural farm transport cost, which subsequently influences the price of food in the country.Practical implicationsThis implies that if the Federal Government of Nigeria is to work toward an ideal agricultural transformation agenda, transport networks should be closely aligned with the GESS priorities to provide connectivity to rural areas that provide most of the country’s agricultural output.Originality/valueThis research adds to the literature on the agricultural and rural development debate in developing countries. It concludes that embracing a rural finance and transportation infrastructure should form the foundation of the ATA in Nigeria, which, in turn, would provide a conducive environment for a more widespread rural economy in sub-Saharan Africa.

Farmyard manure improves phosphorus use efficiency in weathered P deficient soil

Crop production is limited by low soil fertility in sub-Saharan Africa (SSA), particularly by P deficiency due to strong fixation by Fe and Al oxyhydroxides. Organic amendments are known to increase P availability in fertilizer and in such soils by different mechanisms. This study investigated the effect of adding farmyard manure (FYM) versus mineral triple super phosphate (TSP) fertilizer on P availability in different cropping systems. Field experiments were conducted in three succeeding summer seasons to compare two different upland cropping systems: a Bambara (Vigna subterranea)–rice rotation and a rice–rice system on a highly P deficient Ferralsol. Nine treatments including sole TSP at 0, 10, 20, 30 kg P ha−1 year−1, and sole FYM at 0, 10, 20, 30 kg P ha−1 year−1 (i.e. 100% FYM substitution), and combined FYM and TSP (FYM + TSP) at 20, 30 kg P ha−1 year−1 (i.e. 50% and 67% FYM substitution, respectively) were applied. Results showed that FYM treatments increased Bambara and rice grain yields compared to TSP treatment alone particularly in year three. Phosphorus uptake efficiency was higher in FYM treatments combined or not with TSP in year three of the experiment. The notable response to FYM was associated with increased agronomic efficiency resulting from additional C originating from the FYM with a low initial soil C content, (around 2%), and the effect of liming that reduced soil P sorption thereby improving P availability from FYM. Partial (67%) substitution of TSP by FYM increased grain yields of Bambara by 1.67 Mg ha−1 and of rice by 1.01 Mg ha−1 compared to TSP alone in year three at the highest P rate (30 kg P ha−1). The effect of FYM could be linked to inputs of C and nutrients from added FYM and to the indirect effect on soil physico–chemical properties including soil pH, soil moisture, soil biological activity, low P capacity sorption. This study confirms that application of FYM can help minimize rates of TSP applied in smallholder farms in SSA.