Challenges and opportunities to the African agriculture and food systems

Reduction in the proportion of undernourished people worldwide has been achieved despite global population increase. However, the achievement of reducing undernourishment globally was uneven; sub-Saharan Africa (SSA) in particular has the least progress. In SSA, agriculture is only slowly changing with actual well below potential yields. Failures in agricultural policies, weak institutions, and poor governance are the root of growth stagnation. Agriculture contributes a significant share to the SSA economy and a majority of the population derives their livelihood from this sector. It is justifiable to assume that for sustainable growth of the African economy, significant investment and creative innovation in agriculture are needed. However, several factors such as growth of the farming population, loss of soil fertility, climate change, water scarcity, post-harvest losses, and limited market access could challenge such expectation. On the other hand, new policy reforms and initiatives, and appropriate investment that directly or indirectly support agricultural innovation and growth are emerging. This chapter discusses the challenges and opportunities to advance agricultural growth and food systems in Africa and makes recommendations for solutions.Keywords: Africa, food systems, agriculture, agricultural research, agricultural investmen

Enset‐based agricultural systems in Ethiopia: A systematic review of production trends, agronomy, processing and the wider food security applications of a neglected banana relative

Enset (Ensete ventricosum (Welw.) Cheesman) is the major starch staple of the Ethiopian Highlands, where its unique attributes enhance the food security of approximately 20 million people and have earned it the title “The Tree Against Hunger”. Yet enset‐based agriculture is virtually unknown outside of its narrow zone of cultivation, despite growing wild across much of East and Southern Africa. Here, we review historical production data to show that the area of land under enset production in Ethiopia has reportedly increased 46% in two decades, whilst yield increased 12‐fold over the same period, making enset the second most produced crop species in Ethiopia—though we critically evaluate potential issues with these data. Furthermore, we address a major challenge in the development and wider cultivation of enset, by reviewing and synthesizing the complex and fragmented agronomic and ethnobotanic knowledge associated with this species; including farming systems, processing methods, products, medicinal uses and cultural importance. Finally, we provide a framework to improve the quality, consistency and comparability of data collected across culturally diverse enset‐based agricultural systems to enhanced sustainable use of this neglected starch staple. In conclusion, we discuss the challenges and opportunities for enset cultivation beyond its restricted distribution, and the regional food security potential it could afford smallholders elsewhere in Southern and East Africa

Effectiveness of Agronomic Biofortification Strategy in Fighting against Hidden Hunger

Micronutrient deficiencies (MNDs), also known as hidden hunger, affect more than a quarter of the global population. Agronomic biofortification helps to increase the concentration of a target mineral in food crops and improve human mineral dietary intake. It is a means of providing nutrient-dense foods to a larger population, especially among rural resource-poor settings, providing that they have access to mineral fertilizers. However, the feasibility of agronomic biofortification in combating hidden hunger depends on several factors in addition to fertilizer access, including crop type, genotype, climate, soils, and soil mineral interactions. Consideration of its effectiveness in increasing human mineral intake to the daily requirements and the improvement of human health and the cost-effectiveness of the program is also important. In this paper, we review the available literature regarding the potential effectiveness and challenges of agronomic biofortification to improve crop micronutrient concentrations and reduce hidden hunger

Selenium deficiency is widespread and spatially dependent in Ethiopia

Selenium (Se) is an essential element for human health and livestock productivity. Globally, human Se status is highly variable, mainly due to the influence of soil types on the Se content of crops, suggesting the need to identify areas of deficiency to design targeted interventions. In sub-Saharan Africa, including Ethiopia, data on population Se status are largely unavailable, although previous studies indicated the potential for widespread Se deficiency. Serum Se concentration of a nationally representative sample of the Ethiopian population was determined, and these observed values were combined with a spatial statistical model to predict and map the Se status of populations across the country. The study used archived serum samples (n = 3269) from the 2015 Ethiopian National Micronutrient Survey (ENMS). The ENMS was a cross-sectional survey of young and school-age children, women and men. Serum Se concentration was measured using inductively coupled plasma mass spectrometry (ICPMS). The national median (Q1, Q3) serum Se concentration was 87.7 (56.7, 123.0) μg L−1. Serum Se concentration differed between regions, ranging from a median (Q1, Q3) of 54.6 (43.1, 66.3) µg L−1 in the Benishangul-Gumuz Region to 122.0 (105, 141) µg L−1 in the Southern Nations, Nationalities, and Peoples’ Region and the Afar Region. Overall, 35.5% of the population were Se deficient, defined as serum Se < 70 µg L−1. A geostatistical analysis showed that there was marked spatial dependence in Se status, with serum concentrations greatest among those living in North-East and Eastern Ethiopia and along the Rift Valley, while serum Se concentrations were lower among those living in North-West and Western Ethiopia. Selenium deficiency in Ethiopia is widespread, but the risk of Se deficiency is highly spatially dependent. Policies to enhance Se nutrition should target populations in North-West and Western Ethiopi

Communicating uncertainties in spatial predictions of grain micronutrient concentration

The concentration of micronutrients in staple crops varies spatially. Quantitative information about this can help in designing efficient interventions to address micronutrient deficiency. Concentration of a micronutrient in a staple crop can be mapped from limited samples, but the resulting statistical predictions are uncertain. Decision makers must understand this uncertainty to make robust use of spatial information, but this is a challenge due to the difficulties in communicating quantitative concepts to a general audience. We proposed strategies to communicate uncertain information and present a systematic evaluation and comparison in the form of maps. We proposed testing five methods to communicate the uncertainty about the conditional mean grain concentration of an essential micronutrient, selenium (Se). Evaluation of the communication methods was done through a questionnaire by eliciting stakeholder opinions about the usefulness of the methods of communicating uncertainty. We found significant differences in how participants responded to the different methods. In particular, there was a preference for methods based on the probability that concentrations are below or above a nutritionally significant threshold compared with general measures of uncertainty such as the prediction interval. There was no evidence that methods which used pictographs or calibrated verbal phrases to support the interpretation of probabilities made a different impression than probability alone, as judged from the responses to interpretative questions, although these approaches were ranked most highly when participants were asked to put the methods in order of preference

Differences in the nutritional quality of improved finger millet genotypes in Ethiopia

Improved crop genotypes are constantly introduced. However, information on their nutritional quality is generally limited. The present study reports the proximate composition and the concentration and relative bioavailability of minerals of improved finger millets of different genotypes. Grains of finger millet genotypes (n = 15) grown in research station during 2019 and 2020 in Ethiopia, and replicated three times in a randomized complete block design, were analysed for proximate composition, mineral concentration (iron, zinc, calcium, selenium), and antinutritional factors (phytate, tannin and oxalate). Moreover, the antinutritional factors to mineral molar ratio method was used to estimate mineral bioavailability. The result shows a significant genotypic variation in protein, fat and fibre level, ranging from 10% to 14.6%, 1.0 to 3.8%, and 1.4 to 4.6%, respectively. Similarly, different finger millets genotypes had significantly different mineral concentrations ranging from 3762 ± 332 to 5893 ± 353mgkg−1 for Ca, 19.9 ± 1.6 to 26.2 ± 2.7mgkg−1 for Zn, 36.3 ± 4.6 to 52.9 ± 9.1mgkg−1 for Fe and 36.6 ± 11 to 60.9 ± 22µgkg−1 for Se. Phytate (308–360µgg−1), tannin (0.15–0.51mgg−1) and oxalate (1.26–4.41mgg−1) concentrations were also influenced by genotype. Antinutritional factors to minerals molar ratio were also significantly different by genotypes but were below the threshold for low mineral bioavailability. Genotype significantly influenced mineral and antinutritional concentrations of finger millet grains. In addition, all finger millet genotypes possess good mineral bioavailability. Especially, the high Ca concentration in finger millet, compared to in other cereals, could play a vital role to combating Ca deficiency. The result suggests the different finger millet genotypes possess good nutrient content and may contribute to the nutrition security of the local people

The effect of soil properties on zinc lability and solubility in soils of Ethiopia - an isotopic dilution study

Zinc (Zn) deficiency is a widespread nutritional problem in human populations, especially in sub-Saharan Africa (SSA). The Zn concentration of crops consumed depends in part on the Zn status of the soil. Improved understanding of factors controlling the phyto-availability of Zn in soils can contribute to potential agronomic interventions to tackle Zn deficiency, but many soil types in SSA are poorly studied. Soil samples (nCombining double low line475) were collected from a large part of the Amhara Region of Ethiopia, where there is widespread Zn deficiency. Zinc status was quantified by measuring several fractions, including the pseudo-total (aqua regia digestion; ZnTot), available (DTPA (diethylenetriamine pentaacetate) extractable; ZnDTPA), soluble (dissolved in 0.01MCa(NO3); ZnSoln) and isotopically exchangeable Zn, using the enriched stable Zn isotope 70Zn (ZnE). Soil geochemical properties were assessed for their influence on Zn lability and solubility. A parameterized geochemical assemblage model (Windermere Humic Aqueous Model - WHAM) was also employed to predict the solid phase fractionation of Zn in tropical soils rather than using sequential chemical extractions. ZnTot ranged from 14.1 to 291mgkg-1 (medianCombining double low line100mgkg-1), whereas ZnDTPA in the majority of soil samples was less than 0.5mgkg-1, indicating widespread phyto-available Zn deficiency in these soils. The labile fraction of Zn in soil (ZnE as %ZnTot) was low, with median and mean values of 4.7% and 8.0%, respectively. Labile Zn partitioning between the solid and the solution phases of soil was highly pH dependent, where 94% of the variation in the partitioning coefficient of 70Zn was explained by soil pH. Similarly, 86% of the variation in ZnSoln was explained by soil pH. Zinc distribution between adsorbed ZnE and ZnSoln was controlled by pH. Notably, Zn isotopic exchangeability increased with soil pH. This contrasts with literature on contaminated and urban soils and may arise from covarying factors, such as contrasting soil clay mineralogy across the pH range of the soils used in the current study. These results could be used to improve agronomic interventions to tackle Zn deficiency in SSA

Impact of zinc and iron agronomic biofortification on grain mineral concentration of finger millet varieties as affected by location and slope

Background: Food crop micronutrient concentrations can be enhanced through agronomic biofortification, with the potential to reduce micronutrient deficiencies among rural population if they have access to fertilizers. Here we reported the impact of agronomic biofortification on finger millet grain zinc (Zn) and iron (Fe) concentration. Methods: A field experiment was conducted in farmers’ fields in Ethiopia in two locations; over two seasons in one district (2019 and 2020), and over a single season (2019) in a second district. The experimental design had 15 treatment combinations comprising 3 finger millet varieties and 5 soil-applied fertilizer treatments: (T1) 20 kg ha−1 FeSO4 + 25 kg ha−1 ZnSO4 + NPKS; (T2) 25 kg ha−1 ZnSO4 + NPKS; (T3) NPKS; (T4) 30% NPKS; (T5) 20 kg ha−1 FeSO4 + NPKS. The treatments were studied at two slope positions (foot and hill), replicated four times in a randomized complete block design. Results: Grain Zn concentration increased by 20% in response to Fe and Zn and by 18.9% due to Zn addition. Similarly, grain Fe concentration increased by 21.4% in T1 and 17.8% in T5 (Fe). Zinc fertilizer application (p < 0.001), finger millet variety (p < 0.001), and an interaction of Fe and Zn had significant effect on grain Zn concentration. Iron fertilizer (p < 0.001) and interactive effect of Fe fertilizer and finger millet variety (p < 0.01) had significant effects on grain Fe concentration. Location but not slope position was a source of variation for both grain Zn and Fe concentrations. Conclusion: Soil application of Zn and Fe could be a viable strategy to enhance grain Zn and Fe concentration to finger millet grain. If increased grain Zn and Fe is bioavailable, it could help to combat micronutrient deficiencies

Genotypic Response of Finger Millet to Zinc and Iron Agronomic Biofortification, Location and Slope Position Towards Yield

The present study aimed to investigate influence of genotypic differences to zinc and iron agronomic biofortification responses among yield of finger millet. A field experiment was conducted over two seasons in farmers’ fields in Ethiopia (2019, 2020). The experimental design had 15 treatment combinations comprising 3 finger millet varieties and application of different combinations of zinc and iron mineral fertilizers. 5 soil-applied fertilizer treatments (20 kg h-1 FeSO4 + 25 kg h-1 ZnSO4 + NPKS, 25 kg h-1 ZnSO4 + NPKS, 20 kg h-1 FeSO4 + NPKS, NPKS, and 30% NPKS), at 2 locations (Gojjam and Arsi Negelle, Ethiopia), and two 2 slope positions (Foot and hill), replicated four times in a randomized complete block design. Grain yield and biomass were evaluated on plot basis. Plant height, total and productive tiller number, finger length of the longest spike and number of fingers per main ear were measured at maturity stage. The combined soil application of FeSO47H2O and ZnSO47H2O increased yield to Meba variety by 51.6%. Also, ZnSO47H2O fertilizer application increased yield to Urji variety by 27.6%. About 18.3% of yield enhancement of Diga-01 variety was achieved due to the FeSO47H2O fertilizers application. The findings of the present study suggests that the influence of Zn and Fe agronomic biofortification on yield of finger millet could be affected by genotype differences and environmental conditions

Genotypic Response of Finger Millet to Zinc and Iron Agronomic Biofortification, Location and Slope Position Towards Yield

The present study aimed to investigate the influence of genotypic differences on responses to zinc and iron agronomic biofortification among yields of finger millet. A field experiment was conducted over two seasons in farmers’ fields in Ethiopia (2019, 2020). The experimental design had 15 treatment combinations comprising three finger millet genotypes and the applications of different combinations of zinc and iron mineral fertilizers. Five soil-applied fertilizer treatments (20 kg h−1 FeSO4 + 25 kg h−1 ZnSO4 + NPKS, 25 kg ha−1 ZnSO4 + NPKS, 20 kg ha−1 FeSO4 + NPKS, NPKS, and 30% NPKS) at two locations (Gojjam and Arsi Negelle, Ethiopia) and using two slope positions (foot and hill) were replicated four times in a randomized complete block design. Grain yield and biomass were evaluated on a plot basis. Plant height, total and productive tiller number, finger length of the longest spike and number of fingers per main ear were measured at the maturity stage. The combined soil application of FeSO47H2O and ZnSO47H2O increased the yield of the Meba genotype by 51.6%. Additionally, ZnSO47H2O fertilizer application increased the yield of the Urji genotype by 27.6%. A yield enhancement of about 18.3% of the Diga-01 genotype was achieved due to the FeSO47H2O fertilizers’ application. The findings of the present study suggest that the influence of Zn and Fe agronomic biofortification on the yield of finger millet could be affected by genotype differences and environmental conditions