Farmers In sub-Saharan Africa Research Articles

Assessing Suitability of Irrigation Scheduling Decision Support Systems for Lowland Rice Farmers in Sub-Saharan Africa—A Review

Assessing Suitability of Irrigation Scheduling Decision Support Systems for Lowland Rice Farmers in Sub-Saharan Africa—A Review

Use of inorganic fertilizer on climate-smart crops improves smallholder farmers' livelihoods: Evidence from Western Kenya

The main challenges facing smallholder farmers in sub-Saharan Africa (SSA) are soil fertility decline and climate change, culminating in increased food insecurity. The double effect of climate change and soil fertility decline could be devastating among the poor rural smallholder farmers, who solely depend on rain-fed agriculture with little investment in adaptive mechanisms. Using inorganic fertilizers and careful selection of climate-resilient crops such as sorghum could improve the livelihoods of smallholder farmers through improved soil health and crop yields. However, information on the effects of inorganic fertilizer on sorghum production remains uncertain, especially in SSA. We evaluated the effects of inorganic fertilizers on sorghum yields among smallholder farmers in Western Kenya. We conducted a cross-sectional survey and collected data from 300 smallholder sorghum farmers. We employed a multi-stage sampling procedure to collect data from the specific smallholder farmers from the target population. We employed endogenous switching regression (ESR) modeling to control observed and unobserved bias in predicting the effects of inorganic fertilizer use on productivity. Smallholder farmers applied a limited amount of inorganic fertilizer. We established that hired labor, agricultural training, and farmers' perception of soil erosion were significant positive determinants of inorganic fertilizer use. Location and access to weather forecast information were key negative determinants of inorganic fertilizer use. The use of inorganic fertilizer increased crop yields by 14%. The findings suggested that inorganic amendments could promote food security and improve purchasing power, thus enhancing smallholder farmers' capacity to cope with declining soil fertility and climate change-related challenges. Therefore, agricultural policies targeting improved productivity of smallholder sorghum farmers could enhance inorganic fertilizer use while considering the determinants.

How did conservation agriculture go to scale?

Background
 The Foodgrains Bank has an established record working in agriculture and food security with resource constrained, marginalized farmers in sub-Saharan Africa. The three outcome areas of the Scaling-Up Conservation Agriculture in East Africa (SUCA) Program were: the adoption of conservation agriculture systems, an enabling institutional environment, and the promotion of enabling policies. These program areas were expected to yield intermediate outcomes that, together, would lead to the ultimate outcome of improved food security and sustainable livelihoods for smallholder farming households in East Africa. This case study reports on the end-line evaluation of the five-year program.
 Purpose
 To illustrate the overlap between utilization-focused evaluation (UFE) and collaborative approaches to evaluation (CAE). The case study profiles an agricultural intervention, and explores how the evaluation design accommodated the systemic nature of the program.
 Setting
 Scaling-Up Conservation Agriculture in East Africa (SUCA) was a five-year program of the Canadian Foodgrains Bank implemented from 2015-2020 to expand the size and scope of Foodgrains Bank’s work in conservation agriculture in East Africa. The program supported local partners with a target of 50,000 male and female farmers practicing a minimum of 2 of 3 conservation agriculture principles, and to improve food security and sustainable livelihoods for 18,000 of these farmers’ households across three countries. 
 Research design
 The Foodgrains Bank was directly involved in the evaluation design through the definition of evaluation uses and key evaluation questions. Eleven implementing partners in East Africa were involved in primary data collection and some initial analysis.
 Data collection and analysis
 A mixed method approach was used combining quantitative, qualitative, and participatory / visual data collection tools. A robust, intersectional gender lens was applied to the data collection instruments in the form of gender disaggregated data collection and gender-focused questions across most data collection instruments. 
 Findings
 The collaborative process confirmed a sense of ownership by the primary evaluation users over the evaluation design. The evaluation design combined outcome and learning uses that took advantages of the implementing organizations’ commitment to learning. The findings demonstrated the value of the program and produced a framework illustrating the multi-disciplinary approach underlying its success.

Assessment of Existing Gaps among Genders in Maize Value-Chain in Northern Nigeria

Equitable access to production resources, inputs, and technologies by men, women, and youth is a critical success factor for improved livelihoods of maize farmers in sub-Saharan Africa (SSA). This study was conducted to assess the existing gaps among different genders in the maize production value chain in selected northern States of Nigeria. A field survey was conducted in five major maize-producing States of Kaduna, Nasarawa, Niger, Taraba, and Adamawa. Structured questionnaires were administered to 450 maize farming households across the five selected States using a simple random sampling technique. Focus group discussions (FGDs) and Key Informant Interviews (KII) were in the study area. The Integrating Gender into Agricultural Value Chains (INGIA-VC) Analytical Framework was employed to develop the tools for the study. Data were analyzed using descriptive statistics. Results showed that over 82% of the sampled farm households in each State were male-headed households, whilst only 18% were female-headed households. Male farmers cultivated an average 4.2 ha of farmland compared to 1.8 ha cultivated by female farmers for maize production. Male farmers have more access to other production inputs like fertilizers than female farmers. More female farmers (22%) than male farmers (7.6%) purchase improved seeds directly from seed companies. Maize productivity by male farmers was consistently higher (2–2.5 t ha-1) than female farmers that recorded an average of 0.24 t ha-1 across the States. The lower participation of female farmers in maize production compared to male farmers was attributed to the socio-cultural and religious restrictions placed on females that exclude them from public engagements in northern Nigeria. Awareness creation through the traditional rulers and mechanization of some practices will engender more women and youth participation in maize cultivation.

Agronomic and economic performance of legume-legume and cereal-legume intercropping systems in Northern Tanzania

CONTEXTCereal-legume intercropping, a common practice among farmers in sub-Saharan Africa (SSA), is important for crop diversification, soil fertility improvement, household nutrition and climate adaptation. However, cereals often outcompete the intercropped legumes for growth resources resulting in low legume yields. OBJECTIVEThe objectives of this study were: i) assessing the effects of different intercropping options (crop spatial configurations) and maize crop (Zea mays L.) management innovations on productivity and economic benefits to farmers and ii) examining how farmers adapt new intercropping technologies to meet their household food security needs. METHODSThe study was undertaken in six on-farm researcher-designed and managed trials in high and low rainfall agro-ecological zones of Babati District in Tanzania, during four cropping seasons (2018–2021). The cropping systems tested included a sole maize system rotated with a legume-legume intercrop (Doubled-up legume), an innovation involving two maize rows intercropped with two legume species (Mbili-Mbili), maize-legume intercrop both with and without de-topping, maize-legume intercrop (2 maize plants at 50 cm intra-space, de-topped), maize-legume system (maize with vertical leaf architecture) and a farmer practice. The Mbili-Mbili technology adaptation assessment was conducted on 225 farmers during the 2021 cropping season. RESULTS AND CONCLUSIONSOverall, maize grain yields increased by up to 56% in improved compared to farmer intercropping practices (P ≤ 0.05). There were no significant differences in maize grain yield among the improved practices. Significantly higher pigeonpea (Cajanus cajan) yields of between 71% and 113% in 2020 and between 65% and 140% in 2021 were observed under Doubled-up legume and between 63% and 124% under local farmer practices in 2020 than in the improved cereal-legume practices. Across the study period, net revenues of sole maize and Doubled-up legume rotations were both the highest and lowest relative to other intercropping options, depending on the starting phase (US$ 653 sole maize and US$ 326 legume phase starting). These were also associated with the highest variances indicating instability. Mbili-Mbili intercropping system had not only high net revenue i.e., a mean of US$623 per hectare, but also more stable. Farmers perceived that Mbili-Mbili increased food security and 96% were willing to implement the system without project support. SIGNIFICANCEMbili-Mbili is recommended for adoption by farmers because of its potential economic benefits, food security and resilience in the current unpredictable weather and climate patterns.

Limited yield penalties in an early transition to conservation agriculture in cotton-based cropping systems of Benin

Transitioning toward minimum or no tillage is challenging for smallholder farmers in sub-Saharan Africa (SSA), due to the possible yield penalties during the initial years of a transition. Understanding the early impacts of such transitions is crucial in a cash crop such as cotton, on which farmers rely for their income, and is necessary to inform agroecological strategies to cope with both these challenges. This study explores the combined impact of minimum or no tillage and fertilizer regimes on agronomic parameters of cotton–cereal rotations, as practiced by smallholder farmers in Benin. A multilocation experiment was set up in three different agroclimatic zones, namely, Savalou (7°55′41″, 1°58′32″), Okpara (2°48′15″, 7°72′07″), and Soaodou (10°28′33″, 1°98′33″). In each area, the experiment was laid out as a split-plot design with four replications (main plot = soil preparation; subplot = fertilizers regimes). The treatments consisted of three different forms of soil preparation, namely, tillage, strip tillage, and no tillage or direct seeding, and four fertilization regimes, namely, basal mineral fertilizers (BMF, 200 kg ha1 of N14P18K18S6B1 + 50 kg ha1 of urea), BMF + A (200 kg ha1 of calcium phosphate amendment, 22P2O5-43CaO−4S), BMF + C (400 kg ha1 of compost), and BMF + A + C. At all sites, direct seeding led to lower below-ground biomass growth and seed cotton yields compared with conventional tillage in an early transition to conservation agriculture starting from degraded soils (2% to 25%). Weak rooting under direct seeding resulted in lower cotton yields compared with that under tillage (−12%) and strip tillage (−15%). At 45 and 90 days after emergence, cotton plants were shorter under direct seeding compared with tillage (−9% and −13%, respectively) and strip tillage (−23% and −6%, respectively). Fertilizer regimes affected seed cotton yields differently across sites and treatments, with marginal responses within soil preparation methods, but they contributed to increase yield differences between conventional and no tillage. Considering the need for sustainable practices, in the context of degraded soils and poor productivity, such limited yield penalties under CA appear to be a reasonable trade-off in the first year of a transition. Alternatively, the results from the first year of this experiment, which is meant to continue for another 5 years, suggest that strip tillage could be a sensible way to initialize a transition, without initial yield penalties, toward more sustainable soil management.

Resilience Capacity of Farmers in Sub-Saharan Africa: A Case Study of Rice Farmers in Ogun and Niger States, Nigeria

Resilience Capacity of Farmers in Sub-Saharan Africa: A Case Study of Rice Farmers in Ogun and Niger States, Nigeria

Impact of frequency of application on the long-term efficacy of the biocontrol product Aflasafe in reducing aflatoxin contamination in maize.

Aflatoxins, produced by several Aspergillus section Flavi species in various crops, are a significant public health risk and a barrier to trade and development. In sub-Saharan Africa, maize and groundnut are particularly vulnerable to aflatoxin contamination. Aflasafe, a registered aflatoxin biocontrol product, utilizes atoxigenic A. flavus genotypes native to Nigeria to displace aflatoxin producers and mitigate aflatoxin contamination. Aflasafe was evaluated in farmers' fields for 3 years, under various regimens, to quantify carry-over of the biocontrol active ingredient genotypes. Nine maize fields were each treated either continuously for 3 years, the first two successive years, in year 1 and year 3, or once during the first year. For each treated field, a nearby untreated field was monitored. Aflatoxins were quantified in grain at harvest and after simulated poor storage. Biocontrol efficacy and frequencies of the active ingredient genotypes decreased in the absence of annual treatment. Maize treated consecutively for 2 or 3 years had significantly (p < 0.05) less aflatoxin (92% less) in grain at harvest than untreated maize. Maize grain from treated fields subjected to simulated poor storage had significantly less (p < 0.05) aflatoxin than grain from untreated fields, regardless of application regimen. Active ingredients occurred at higher frequencies in soil and grain from treated fields than from untreated fields. The incidence of active ingredients recovered in soil was significantly correlated (r = 0.898; p < 0.001) with the incidence of active ingredients in grain, which in turn was also significantly correlated (r = -0.621, p = 0.02) with aflatoxin concentration. Although there were carry-over effects, caution should be taken when drawing recommendations about discontinuing biocontrol use. Cost-benefit analyses of single season and carry-over influences are needed to optimize use by communities of smallholder farmers in sub-Saharan Africa.

Anthropogenic Land Use Change and Adoption of Climate Smart Agriculture in Sub-Saharan Africa

Compelling evidence in Sub-Saharan Africa (SSA) shows that Climate-Smart Agriculture (CSA) has a positive impact on agricultural productivity. However, the uptake of CSA remains low, which is related to anthropogenic, or human-related, decisions about CSA and agricultural land use. This paper assesses households’ decisions to allocate agricultural land to CSA technologies across space and over time. We use the state-contingent theory, mixed methods, and mixed data sources. While agricultural land is increasing, forest land is decreasing across countries in SSA. The results show that household decisions to use CSA and the extent of agricultural land allocation to CSA remain low with a negative trend over time in SSA. Owned land and accessing land through rental markets are positively associated with allocating land to CSA technologies, particularly where land pressure is high. Regarding adaptation, experiencing rainfall shocks is significantly associated with anthropogenic land allocation to CSA technologies. The country policy assessment further supports the need to scale up CSA practices for adaptation, food security, and mitigation. Therefore, scaling up CSA in SSA will require that agriculture-related policies promote land tenure security and land markets while promoting climate-smart farming for food security, adaptation, and mitigation.

A review of the adaptive capacity of sweet sorghum to improve food security and poverty alleviation in sub-Saharan Africa

• Sweet sorghum can address socioeconomic challenges for African smallholder farmers. • A neglected multiuse crop, it is utilised for food, fuel, fibre, and fodder. • This grain crop can grow under water limited- and low nutrient input conditions. • Adoption of sweet sorghum in smallholder farming requires investment in research. Current challenges facing smallholder farmers in sub-Saharan Africa (SSA) require holistic adoption of crops that have diverse socioeconomic and agronomic significance. Sweet sorghum, an underutilised grain crop, has such potential, especially for bioethanol production, due to its adaptation to harsh conditions. Despite being native to SSA, its neglect and underuse is a concern given its wide potential to improve socioeconomic conditions of farmers in this region. This review highlights sweet sorghum's potential by discussing its adaptive capability against major production constraints such as water availability, soil nutrition, plant population, planting date, and harvest time. The review highlights sweet sorghum as a crop that maximises its growth and development under water stress conditions due to its high-water use efficiency. Furthermore, sweet sorghum can be cultivated under marginal soils compared to its biofuel counterparts (e.g., maize, sugarcane, and sugar beet) and can still be high yielding (grain) at high plant densities, with early planting dates also resulting in high yields. These attributes are significant in smallholder farming systems due to their susceptibility to socioeconomical and agronomic challenges. In addition, it was identified that there is lack of research relating to pests and diseases that plague sweet sorghum, with some measures and recommendations being based on grain sorghum. Therefore, the need for research and development on sweet sorghum in SSA may not only intensify its benefits to farmers but can also improve efficient cultivation under local environmental conditions.

Profitability and agronomic potential of cotton (Gossypium hirsutum L.) under biochar-compost-based amendments in three agroecological zones of northern Benin

Low land productivity is a major constraint facing agriculture in sub-Saharan Africa, which severely affects crop yields, particularly cotton which is main export agricultural produce of Northern Benin. To overcome this situation, the hill-placement of microdose biochar-compost-based amendments was carried out at two research stations and on farmer's fields in three agroecological zones of northern Benin. The study aims to evaluate the agronomic and economic performance of cotton under two types of compost and biochar-based amendments. On stations, the experimental design used was a complete randomized block with one factor and ten treatments replicated four times as follows: (i) absolute control without any amendment (Ck), (ii) mineral fertilizer (MF) at 200 kg/ha, (iii) cow dung-based compost at 200kg/ha (CP1_200) and (iv) 300kg (CP1_300), (v) household waste-based compost at 200kg/ha (CP2_200) and (vi) 300 kg (CP2_300), the combination of CP1 and 15% biochar designated Terra preta (TP) applied at 200kg/ha (vii, TP1_200) and 300kg/ha (viii, TP1_300), the combination of CP2 and 15% biochar applied at 200kg/ha (ix, TP2_200) and 300kg/ha (x, TP2_300). On-farms, the experimental design was a randomized complete block with one factor and six optimal treatments extracted from the on-station experiments with three replicates installed in four farmers' fields from each location studied. The six treatments were: Ck, MF, CP1_200, CP2_200, TP1_200 and TP2_200. Cotton growth (Plant height, number of vegetative and reproductive branches and total bolls per plant) and yield data were collected. The treatment TP1_300 yielded higher cotton seed with 2.53 t/ha, i.e., 86% more than the absolute control. However, the highest plant growth parameters were obtained with MF which were similar to those obtained with TP1_300 (P &amp;gt; 0.05). Likewise, at farms, the highest plant growth parameters and yield were observed with MF followed by TP1_200 (with a cotton seed yield increase of 146% compared to the control, P &amp;lt; 0.05). In addition, no significant differences were observed between organic fertilizers treatments for growth variables. However yield differences occurred. To resume, TP1_300 kg/ha performed best in terms of growth and yield in on-station experiments, while on-farms, TP1_200 kg/ha produced the highest responses of cotton. Value Cost Ratio (VCR) and Benefit Cost Ratio (BCR) values were generally as good or even better for MF treatment and treatments involving CP1 at both on station and on farm, compared to Ck. Although applying mineral fertilizer (MF) alone as currently done by many farmers appears to make economic sense, this practice is unlikely to be sustainable in the long term. Applying TP1_200 and TP1_300 are two possible strategies that are affordable to farmers and provide returns on investment at least as good as the current practice of sole application of MF. However, a long-term study to assess the effect of compost-activated biochar on crop productivity and soil quality is advised.

The possibilities of explicit Striga (Striga asiatica) risk monitoring using phenometric, edaphic, and climatic variables, demonstrated for Malawi and Zambia.

Food insecurity continues to affect more than two-thirds of the population in sub-Saharan Africa (SSA), particularly those depending on rain-fed agriculture. Striga, a parasitic weed, has caused yield losses of cereal crops, immensely affecting smallholder farmers in SSA. Although earlier studies have established that Striga is a constraint to crop production, there is little information on the spatial extent of spread and infestation severity of the weed in some SSA countries like Malawi and Zambia. This study aimed to use remotely sensed vegetation phenological (n = 11), climatic (n = 3), and soil (n = 4) variables to develop a data-driven ecological niche model to estimate Striga (Striga asiatica) spatial distribution patterns over Malawi and Zambia, respectively. Vegetation phenological variables were calculated from 250-m enhanced vegetation index (EVI) timeline data, spanning 2013 to 2016. A multicollinearity test was performed on all 18 predictor variables using the variance inflation factor (VIF) and Pearson's correlationapproach. From the initial 18 variables, 12 non-correlated predictor variables were selected to predict Striga risk zones over the two focus countries. The variable "start of the season" (start of the rainy season) showed the highest model relevance, contributing 26.8% and 37.9% to Striga risk models for Malawi and Zambia, respectively. This indicates that the crop planting date influences the occurrence and the level of Striga infestation. The resultant occurrence maps revealed interesting spatial patterns; while a very high Striga occurrence was predicted for central Malawi and eastern Zambia (mono-cultural maize growing areas), lower occurrence rates were found in the northern regions. Our study shows the possibilities of integrating various ecological factors with a better spatial and temporal resolution for operational and explicit monitoring of Striga-affected areas in SSA. The explicit identification of Striga "hotspot" areas is crucial for effectively informing intervention activities on the ground.

Adoption of climate-smart agricultural practices by smallholder farmers in rural Ghana: An application of the theory of planned behavior

Climate-Smart Agricultural (CSA) practices are crucial in managing climatic shocks faced by smallholder farmers in sub-Saharan Africa. However, evidence on the socio-psychological drivers of farmers’ adoption of CSA practices remains limited. This study employed the Theory of Planned Behavior framework to analyze smallholder farmers’ intention and adoption behavior toward CSA practices in rural Ghana. The study sampled 350 smallholder farmers from the Upper East and North-East Regions of Ghana and employed the Structural Equation Model to understand smallholder farmers’ intention and adoption behavior toward CSA practices. Results showed that farmers’ attitudes (notably their beneficial evaluation of CSA practices) had a significant impact (0.25) on their intention to adopt CSA practices. Social pressure exerted on farmers to use CSA practices (Subjective norm) also had a significant impact (0.52) on farmers’ adoption behavior. Perceived behavior control which measures the controllability and use of CSA practices also had a significant impact on both the intention (0.43) and adoption behavior (0.20) of smallholder farmers. Findings highlight the role socio-psychological factors play in explaining the adoption of CSA practices in rural Ghana. We recommend the need to create awareness of CSA practices by sharing relevant information more widely on CSA practices through community leaders, chief farmers, assembly members, and clan heads in order to exert influence on farmer’s adoption of CSA practices.

Bambara groundnut production, grain composition and nutritional value: opportunities for improvements

AbstractBambara groundnut (Vigna subterranea L. Verdc; BGN) is an important legume grown mainly by small-scale subsistence farmers in sub-Saharan Africa, in parts of Thailand and Indonesia. It has a high concentration of seed carbohydrate (55–70%), protein (17–25%), fat (1.4–12%) and dietary fibre (5.2–6.4%). A range of biotic and abiotic stresses together with socio-economic constraints affect its productivity, yield and quality. The changing climate and a growing world population are putting pressure on food production, as world food supply is heavily reliant on few crops. As such, there is a need to broaden crop usage and increase yield of minor crops such as BGN. Improvements in production can potentially be achieved by a combination of advanced phenotyping, genotyping, environmental characterization and overall management approaches. Breeding for advanced lines is complicated by overreliance on landraces. This review aims to provide the current status of BGN production, production constraints and approaches to overcome these, as well as its grain composition and nutritional value. It further discusses and elaborates on potentially available opportunities for overall improvement, so that BGN, like all neglected crops, can play a valuable role in world food security. Efforts should be intensified to improve the overall utilization of BGN and its constituents to make it an economically viable crop.

Agricultural Land-Use Systems and Climate Change among Small Farmers in Sub-Saharan Africa: Relationship and Evidence of Adaptive Processes in Nigeria

Agricultural Land-Use Systems and Climate Change among Small Farmers in Sub-Saharan Africa: Relationship and Evidence of Adaptive Processes in Nigeria

TECHNICAL EFFICIENCY IN COWPEA (Vigna unguiculata) PRODCTION IN KANKE, PLATEAU STATE, NIGERIA

Cowpea farmers in sub-Saharan Africa obtain low yields; sole cropping system with the use of improved technologies can yield 1,500-2,000 kg/ha of cowpea. However, 200-500 kg/ha yield is obtained by smallholder farmers. It is a multipurpose crop and despite its importance, high level of inefficiency in its production persists. Therefore, the determinants of efficiency in cowpea production were analyzed; the decline in cowpea yield in the study area was attributable to several socioeconomic variables. Multistage sampling technique was used to select 70 cowpea farmers from the study area. Primary data was collected using structured questionnaires. Descriptive statistics and stochastic frontier production function were the analytical techniques adopted. The results indicated that the socioeconomic characteristics of the respondents significantly affected cowpea production. The mean technical efficiency index was 0.59. Furthermore, the stochastic frontier analysis revealed that coefficients of farm size (0.297), labour (0.394), quantity of seed (0.433) and agrochemicals (0.057) were all positive and statistically significant. Also, the inefficiency model revealed that the coefficients of household size (-0.284), education (-0.493) farm experience (-0.402), extension contact (-0.45) and access to credit (-0.255) were negative but statistically significant Thus, the significant variables were the determinants of technical efficiency in cowpea production. The identified constraints adversely affected farm productivity and efficiency. Formation of cooperatives, adoption of measures that improve access to agricultural credit, agro-services centers, input supply, technology transfer and subsidies; extension services, information exchanges and market linkages are recommended to mitigate technical inefficiency in cowpea production among smallholder farmers.

Do youth farmers benefit from participating in contract farming? Evidence from French beans youth farmers in Arusha, Tanzania

ABSTRACT Contract farming (CF) is often seen as a system that enhances production efficiency leading to increased agricultural productivity and improved farmer livelihoods. However, there is a conflict in the literature on its impact on young farmers who are involved in farming in Sub-Saharan Africa. This paper evaluates the impacts of CF on crop yield, crop and household income among the youth farmers involved in French bean farming in Tanzania using cross-sectional data of 273 households. The study employs an endogenous switching regression (ESR) model that accounts for observed and unobserved factors to estimate the impact of CF. Further, the propensity score matching (PSM) model is used to check the robustness of ESR results. The results indicate that 162 farmers had contracts and French bean yields and incomes significantly increased with CF. Specifically, the empirical results reveal that CF leads to a gain of 17%, 34% and 37.5% in the yield, crop income and household income. Participation and impact of contract farming differed according to different socio-economic/institutional variables, such as access to extension services.

Climate change and its impact on urban agriculture in Sub-Saharan Africa: A literature review

Abstract Recent surveys have shown that the global urban population is increasing at an accelerated rate. As a result, the associated increased demand for food items has pushed up the overall cost of living for urban dwellers. To mitigate this increased cost of living urban dwellers increasingly find solace in agricultural activities. This surge in urban agricultural activities comes at a time characterized by long term shifts in temperatures, rainfall patterns and general weather conditions. While many researchers have presented evidence of increased urban agricultural activities, there remains a paucity of integrated literature that summarizes climate change issues on urban agriculture. This research reviewed literature on the influence of climate change on urban agricultural operations in sub-Saharan African cities. A narrative review approach was employed to summarize and synthesize findings and make recommendations for future research. The review employed the key terms ‘urban farming’, ‘urban agriculture’, ‘climate change’, ‘peri-urban agriculture’, and ‘urban agricultural production’ to search relevant literature indexed in databases: Scopus, Directory of Open Access Journals, Web of Science, Google Scholar and Academic Search (EBSCO). The choice of these keywords was informed by the authors’ specialist understanding of urban agriculture and climate change. There is consensus among the reviewed literature that climate change affects urban agriculture from production to processing, storage, and distribution. This study also established that the extent and magnitude of climate change impacts differ from one region to another. Therefore, adaptation and mitigation strategies ought to be context specific and not universally applicable. This is important because Africa is a climatologically diverse continent so that the impact of climate change faced by one sub-Saharan African city may be different from that for other cities in other regions. A framework that simplifies the effects of climate change on urban agriculture-dependent households in sub-Saharan Africa was produced. More specifically, this framework is recommended to those urban farmers and policymakers that are involved in mitigating the consequences of climate change as well as achieving food and nutritional security. The authors also recommend this framework for unpacking the knowledge of the influence of climate change on urban agriculture as well as exposing directions for future research. This work adds to the growing body of knowledge in the domain of climate change on urban agriculture-dependent households.

Modeling sorghum-cowpea intercropping for a site in the savannah zone of Mali: Strengths and weaknesses of the Stics model

Intercropping is a key entry point for sustainable intensification of cropping systems in sub-Saharan Africa where variable rainfall conditions prevail. Crop simulation models can complement field experiments to assess the agronomic and environmental performances of intercropping systems under diverse climatic conditions, including hypothetical future climate. So far, crop models that can handle intercropping, such as STICS, have not often been extensively evaluated for tropical conditions and for species grown by farmers in sub-Saharan Africa. The objective of this study was to evaluate the performance of the calibrated STICS model to simulate sorghum-cowpea intercropping systems in rainfed conditions in West Africa. We used data from field experiments conducted at the N'Tarla Agronomic Station in Mali in 2017 and 2018. Two varieties of sorghum (local and improved) with contrasting photoperiod sensitivities were grown as sole crop and intercropped with cowpea, with additive design. Two sowing dates and two levels of mineral fertilization were also investigated. Model simulations were evaluated with observed data for phenology, leaf area index (LAI), aboveground biomass, grain yield and in-season soil moisture. Large variations in aboveground biomass of sorghum and cowpea was observed in the experiment (i.e. 3.5 – 9.6 t/ha for sorghum and 0.4–2.5 t/ha for cowpea), owing to the treatments (i.e. sole vs intercrop, early vs late sowing, no fertilizer input vs fertilizer input). Such variations were satisfactorily reproduced by the model, with EF of 0.81 in calibration and 0.58 in evaluation (with relative rRMSE of 23 % and 43 %) across crops. Sorghum AGB simulations were more accurate (rRMSE of 21 % and EF of 0.54) than cowpea AGB simulations (rRMSE of 25 % and EF of −0.09). The two main observed features of the intercropping system were well reproduced by the model. Firstly, cowpea and sorghum aboveground biomass decreased with intercropping compared with sole cropping, and the decrease in cowpea biomass was greater than the decrease in sorghum biomass. Secondly, despite a reduction in sorghum and cowpea yield, Land Equivalent Ratio of the intercropping for aboveground biomass was always above one. With regard to grain yield, observed LER was above one only in the non-fertilized treatment. The model failed at reproducing this behavior, probably because of insufficiently accurate calibration of the process leading to grain yield formation: rRMSE for grain yield was 49 % in calibration and 41 % in evaluation. Based on these findings, we discuss avenues to improve model calibration and use the model to explore options for sustainable intensification in land constrained sub-Saharan Africa. • Accurate STICS simulations of intercropped sorghum and cowpea aboveground biomass. • Inaccurate STICS simulations of intercropped sorghum and cowpea grain yield. • The model can be used to start exploring inter-annual performance of intercropping. • Experiments looking at N dynamics in intercropping needed to refine calibration.

Selection of an Appropriate Biomass Burner for Drying Maize in a Crossflow Column Dryer Using an Analytic Hierarchy Process

Several post-harvest technologies have been introduced over the past years to help smallholder farmers in sub-Saharan Africa reduce crop losses. However, not all these technologies fit the same application purpose to meet the needs of farmers in different locations. This study, therefore, applied a multi-criteria decision method, the analytical hierarchy process (AHP), to select an appropriate biomass burner based on its technical performance, cost, and design criteria to complete the setup of a low-cost column dryer. With a priority value of 0.69 out of 1.00, the KNUST-ABE Biomass Burner was selected over the AFLASTOP Biomass Burner which had a priority value of 0.31 out of 1.00. Based on the results of this study, the AHP multi-criteria decision method was helpful in the selection of a locally developed biomass burner for a low-cost column drying system.