Soil degradation in Sub-Sahara Africa
The conflict between food security and climate mitigation, and paths for climate-smart solutions
Soil degradation
Soil health in Sub-Sahara Africa (SSA) is in a critical state. 10 Nutrient deficiency is common in SSA due to a myriad of reasons. Nutrients are stripped from the soil when plants or grazing animals remove native nutrients without substitution, through run-off, leaching, emissions and volatilization. 10 Nutrients also get fixated in chemical complexes, making them unavailable to plants. 10 Effective nutrient management is needed to replenish missing nutrients and ensure soil health and quality in the future. 12 A lack of essential nutrients and poor soil quality overall can cause a significant decrease in agricultural production and create more variability. 12
Sanchez (2002) reports that in the past 30 years, an average of 660 kg of nitrogen (N), 75 kg of phosphorus (P), and 450 kg of potassium (K) per hectare have been lost from about 202 million hectares of cultivated land across 37 African countries. This amounts to an estimated annual nutrient loss of 8 million tons of NPK in Sub-Saharan Africa.
SSA's soils are in bad condition but who do the depleted soils have to feed?
Total population in Sub-Saharan Africa and estimates up to the year 2100
The global population is projected to reach around 9 billion by 2050. 36 Sub-Sahara Africa is expected to contribute significantly to this growth. 36 It is predicted that SSA's population will steadily grow till the end of the century, from 1.4 billion in 2030 to 2.17 billion in 2050. 36
Given this expected population expansion, the food demand and pressure on food security will increase substantially. 10 Food insecurity is a global concern under the Sustainable Development Goals (SDGs), with 720 million to 811 million people experiencing hunger in 2020. 10 In Africa, particularly Sub-Saharan Africa, this issue is even more severe, affecting 21% of the population, or 278 million people. 10
Depleted soils and a hungry, expanding population... and who has to provide?
Global mapping of field size
This region's agriculture is primarily driven by smallholder farmers, who play a crucial role in economic growth, poverty reduction, rural development, and food security. 37 Recent estimates suggest the presence of approximately 33 million smallholder farms in SSA, typically cultivating less than 10 acres each. 18 These small farms make up over 80% of all farms in Sub-Saharan Africa and contribute up to 90% of agricultural production. 3 Agriculture is the backbone of the African economy and the largest sector supporting the economic and social lives of many in Sub-Saharan Africa. Agriculture employs more than 65% of the Sub-Saharan labor force and generates about 32% of the GDP. 27 Leveraging the potential of smallholder agriculture can lead to social development, sustainable food systems, income equality, improved living conditions, and job opportunities, particularly for rural communities. 27
These smallholders bear the weight of providing for the continent, but as they try to ensure food security, often another problem arises. In many cases measures that enhance food security increase direct and indirect GHG emissions.
But what can smallholders do when they seem to have a decision between covering the food demand or mitigating climate change?
Food security vs. mitigation
Nutrient management for food security
Common practices for ensuring food security focus on nutrient management. As the soils in SSA are depleted of N, P and K, substitution of these nutrients via fertilizers directly helps increase plant productivity. 20 N fertilization can result in increased organic matter input into soil through roots, resulting in enhanced soil carbon sequestration. 20
Recent research has suggested that the use of synthetic fertilizer among smallholders is far more common than was previously thought. 20,32 Additionally, nitrogen fertilizer use in SSA is projected to rise from 0.9 million tons in 2015 to 1.2 million tons by 2030. 34
Fertilizer application per hectare of land used for crop production in Sub-Sahara Africa
On the one hand fertilizer use in Sub-Sahara Africa is low compared to the global average. On the other hand the growth in fertlizer use per hectare and yield is significantly higher than the global average, as can be seen below. This indicates that the effectiveness and impact of fertilizer use is distinctly lower in SSA than it is in the rest of the world.
Change in N-fertiliser application per hectare and yields for maize, 2023 to 2032
Nutrient management and greenhouse gas emissions
Ensuring food security sustainably is crucial for poverty alleviation in the developing world. 38 To address this challenge, crop producers often overuse inputs like chemical fertilizers and pesticides, leading to environmental degradation like eutrophication. 38
Non-CO 2 greenhouse gases (N 2 O, CH 4 , and fluorinated gases) significantly contribute to climate change, with the agriculture sector being the largest emitter. 33 The rise in global GHG emissions from agriculture is mainly due to the increased use of synthetic fertilizers and pesticides. 20 Agricultural ecosystems are maintained in a state of chemical nutrient saturation leading to nutrient losses through leaching, runoff, volatilization, emissions, and low nutrient-use efficiency in agricultural ecosystems. 38
Trade-offs between food security and mitigation
On one hand, increasing the use of N fertilizer, specifically synthetic fertilizer, would be a simple and direct way of increasing crop productivity and minimizing variability on depleted soil, therefore increasing food security. 20 On the other hand, this would rapidly increase N 2 O emissions and create an immense challenge for climate change mitigation. 20
Combining food security and climate mitigation
To reverse negative environmental trends, it's crucial to identify strategies for more productive and sustainable agricultural development. Increased crop production must not harm the environment. 38 Sustainable agricultural development should include agro-ecological approaches that conserve resources, mitigate environmental impacts, and address climate change. 38 Balanced fertilization and nutrient management can significantly reduce chemical input and greenhouse gas emissions. 40,41 Therefore, adopting integrated strategies with lower environmental impact to ensure food security will become more and more significant in SSA. 20
Integrated approaches
Why use integrated approaches for soil health: To boost crop production without significantly increasing GHG emissions in smallholder farming in Sub-Saharan Africa, it's essential to adopt integrated approaches that address not just yield, variability, N input or any other issue by itself, but instead look at soil health and agricultural management as a whole system. 20 In the following chapter examples of integrated approaches are presented that apply this concept at different levels.
Organic fertilizer
Possible sources of organic fertilizer
What are organic fertilizers: Organic fertilizers are derived from natural sources like farmyard manure, green manure, compost, and household waste. In addition to providing essential nutrients, organic fertilizers enhance the physical structure and biochemical activity of the soil. 37 One key benefit of organic fertilizers is their gradual nutrient release through the slow decomposition of organic matter. This steady decomposition process regulates the addition and accumulation of organic matter in the soil, helping to maintain a balanced soil organic matter content. 22 Organic fertilizer use is also linked with lower N 2 O emissions that are attributed to the slow initial release and immobilization of mineral nitrogen, which reduces the amount of nitrogen available to be lost as N2O. 20
Organic fertilizers represent a sustainable approach to farming by maximizing the use of local natural resources, offering environmental benefits, being more cost-effective, and avoiding GHG emissions related to synthetic fertilizers. 10
Challenges for utilization of organic fertilizer: Smallholder farmers in SSA face numerous challenges in using organic fertilizers. These include the slow action of organic fertilizers, labor-intensive application processes, limited sources of manure, higher costs, storage issues, the emergence of weeds, and the unpleasant smell of some organic fertilizers. 20,22,37 Moreover, there is often a lack of skills and technical knowledge, along with inadequate access to extension services that provide necessary technical advice. 22,37
Biofertilizer
What are biofertilizers: Biofertilizers, or microbial bio-inoculants, are an important type of fertilizer for climate-smart agriculture. These are formulations containing active or dormant strains of microorganisms—mainly bacteria, but sometimes combined with algae or fungi—that enhance nutrient mobilization in the soil. 22,27 They come in various forms, including solid, powdered, granular carrier materials, or liquids, which support the microbial inoculants and extend the product's shelf life. 27
Biofertilizer technology employs plantmicrobe interactions in influencing plant growth and development
How do biofertilizers work: Biofertilizers like Rhizobium, Azotobacter, Azospirillum, Pseudomonas, and Bacillus are crucial in sustainable farming due to their environmental benefits, cost-effectiveness, and ability to boost productivity. 27,28 The beneficial microbes in biofertilizers can be rhizospheric, meaning they colonize the surface or intercellular spaces of plant roots, or endophytic, meaning they inhabit the tissue or apoplastic space within host plants. 27,28 They enhance plant nutrition and yield through biological nitrogen fixation, nutrient solubilization, biocontrol activities, and the production of plant growth-promoting substances. 27,28 These microorganisms also stimulate microbial activity, accelerate decomposition processes, and are less likely to cause resistance in pathogens and pests. 27,28
Challenges in utilization: The limited use of biological fertilizers like fungi or algae in agriculture stems from several factors. Firstly, their production and application can be costlier than chemical fertilizers, posing economic challenges for many farmers. 27,28 Secondly, biological fertilizers often demand specific growth and application conditions, adding complexity to their management compared to chemical counterparts. 27,28 Thirdly, their effectiveness varies based on soil type, climate, and crop species, sometimes yielding inconsistent results. 27,28 Moreover, biological fertilizers may not be as readily available or accessible as chemical alternatives, particularly in remote areas. 27,28 Finally, limited research and education about their benefits and proper usage contribute to a lack of awareness among farmers about their potential advantages. 27,28
Integrated nutrient management
What is integrated nutrient management: For farmers to reach their full potential, a shift toward sustainable, low-cost, and efficient integrated nutrient management (INM) is essential. 37,38 INM combines reduced use of inorganic fertilizers with organic materials like animal manure, crop residues, green manure, and composts. 37,38 Practices include using farmyard manure, soil amendments, natural and chemical fertilizers, green manures, cover crops, intercropping, crop rotations, fallows, conservation tillage, irrigation, and drainage. 37,38
Grain yield (top left), N surplus (top right), reactive N losses intensity (bottom left) and GHG intensity (bottom right) for ISSM compared with the current practice. “*” indicates significant difference between ISSM and current practice according to LSD (0.05)
Benefits of integrated nutrient management: This approach sustains soil fertility, boosts microbial biomass, and enhances overall soil health. 37,38 INM practices reduce reactive nitrogen losses and greenhouse gas emissions without compromising crop yields. 37,38
In the figures on the right the impact of integrated soil-crop system management (ISSM), of which integrated nutrient management is the key principle, on soil N, crop yield and GHG emissions can be seen. 38
In their literature review Wu & Ma (2014) summarize that INM can increase crop yields by 8–150%. Additionally, compared to conventional methods, INM improves water-use efficiency, and provides better economic returns. 37,38 INM optimizes nutrient cycling, synchronizing crop nutrient demand with release, and minimizes losses through leaching, runoff, volatilization, and immobilization. 37,38
Land-water-nutrient-nexus
Why use an overall integrated approach: Beyond just addressing soil health through nutrient management, it can be strategic to adopt integrated approaches that enhance land, water, and nutrient management holistically and combine different approaches from varying perspectives, while minimizing trade-offs and maximizing synergies. 20
Land-Water-Nutrient Nexus (LWNN) approach in smallholder crop farming systems in Sub-Saharan Africa. ↑: increase and ↓: decrease
Local studies on the effectiveness: Research in Kenya and Tanzania has shown that combining water harvesting techniques, like tie ridges, with manure or inorganic fertilizers leads to higher yields of maize or cowpea compared to using these methods separately. 17,19,21 Similarly, in semi-arid West Africa, techniques such as stone bunds, zaï pits, and half-moons, when used with organic and/or mineral fertilizers, have been found to increase agricultural productivity and carbon sequestration. 42
Benefits of the LWNN approach: Therefore, by utilizing the LWNN (Land, Water, and Nutrient Nexus) approach, it is possible to enhance crop production while also mitigating GHG emissions. 20
Factors for implementation
But how can new approaches and practices find their way into utilization in smallholder farming? To implement new integrated approaches smallholders, especially subsistence farmers, face immense barriers. They need many ressources like money, laborforce, knowledge and many more.
But do smallholders and subsistence farmers have those ressources? Can they manage the change alone?
Factors for technology adoption and the "Leaky bucket"
Ressources flowing in and leaking from the holes in the bucket
When talking about the factors and barriers for the implementation of climate-smart practices, especially integrated approaches, the metaphor of the "leaky bucket" can be used. The water in the bucket represents ressources. The bucket has holes in different heights through which water can drip out. These holes represent factors or barriers in the way of implementation. The leaky bucket is meant to show that the water never rises above the lowest hole, meaning the factor hindering implementation that is situated the lowest (meaning it is in the worst condition) will limit the whole process and will inhibit any further improvement.
In the following chapter the factors that have a significant impact on the adoption of new technologies, meaning machinery as well as practices, management systems and other improvements, will be explained. In accordance with Fadeyi et al. (2022) they will be summarized into five categories: Farmers' Characteristics, Farm Characteristics, Technology Characteristics, Institutional Factors and Finance.
Farmers' characteristics
The research highlights various factors influencing technology adoption among smallholder farmers in Africa. Key characteristics include age, gender, education, marital status, household size, off-farm income, farming experience, group membership, attitude, culture, and religion. 4,5,12,20,39
Older farmers tend to show less interest in new technologies. 12,39 Gender also plays a role, with men generally adopting new technologies faster than women. 12,39 Education positively impacts adoption rates, as educated farmers are quicker to embrace new methods. 26 Marital status influences decisions, and larger household sizes, indicating greater financial commitments, often hinder technology adoption. 12 Off-farm income supports adoption by providing additional financial resources. 12
Experience in farming is crucial; more experienced farmers better understand the need and extent of new technologies. 12,4,5 Limited experience and lack of information slow down adoption rates. 12,4,5 Social group membership enhances peer learning and knowledge sharing, promoting technology adoption. 23
Overall, these factors collectively shape smallholder farmers' decisions to adopt new technologies.
Farm characteristics
Access to extension services is crucial for technology adoption among smallholder farmers in Africa. 12,4,5 Extension agents educate farmers about new technologies and their benefits, boosting adoption rates. Farm size also plays a significant role; larger farms are more likely to adopt new technologies quickly. 12,39
Higher farm income enables farmers to adopt newer technologies, and the availability of labor is also a key factor. 12 Land ownership structure influences technology adoption, with secure ownership encouraging adoption and insecure ownership hindering it. 4,5,39
The proximity of farms to markets and technology sources affects adoption rates as well. 12 Farms closer to city centers, where many agricultural research institutes are located, receive and adopt new technologies more quickly. 12
Technology characteristics
For smallholder farmers to adopt new technologies, these technologies must be accessible and well-understood. 4,5,12,39 Ochieng et al. (2019) found that farmers adopt technologies they are knowledgeable about, but Abdul-Hanan (2017) noted that awareness alone is not enough. Farmers need to understand the technology's application and benefits. 1 Training in usage and maintenance is crucial for long-term adoption. 1
Farmers are more likely to adopt technologies they perceive as useful, compatible with their needs, and easily adaptable to their farms. 1 The net cost, including acquisition and operating expenses, is a significant factor; high costs often deter adoption. 31 Additionally, Senyolo et al. (2018) observed that African smallholder farmers avoid costly technologies. Ease of use, both physically and mentally, also influences adoption rates. 31
Institutional factors
Government policies also play a crucial role, as policies promoting specific technologies lead to faster adoption due to provided training and support. 12,20 Additionally, the availability of basic infrastructure, such as roads and water, impacts farmers' decisions to adopt new technologies. 12,20
Finance
Finance significantly influences technology adoption among smallholder farmers in Africa. 12,4,5 Many studies report a strong correlation between access to finance and the ability to adopt new technologies due to their high costs. 4,5,12,39 Financial resources empower farmers to purchase, operate, and maintain new technologies, as well as hire labor, acquire land, and receive necessary education and training. 4,5,12,39
Farm income, from the sale of farm products and services, and off-farm income, from non-farm activities, both play roles in financing technology adoption. 26 Financial support from banks, government agencies, or other institutions is crucial. 26 The availability, accessibility, and affordability of finance are key factors in technology adoption. 26 Additionally, finance provides a safety net for farmers to explore alternatives if the new technology fails. 26
ABCD Approach - Asset-based Community-led Development
Fixing the leaky bucket is a complex, interdisciplinary, long-term goal, that will benefit by being addressed in an integrated way, empowering the local communities and addressing a myriad of factors for implementation. 15,29
Traditionally, technology adoption and diffusion have followed a top-down approach, where agencies make decisions, plan strategies, and implement processes. 15,29 This method often results in questionable success rates due to its dependence on how the top actors deploy the technology. 15,29 Additionally, these technologies are frequently inaccessible to users due to high costs and large scales. 12,26
Asset-Based Community-Driven Development (ABCD) is a bottom-up, rural development approach that prioritizes local context and sustainability. 15,29 ABCD tools enable communities to define their development priorities based on their unique assets, identities, interests, and preferences. 15,29 Rooted in community economic development, participatory rural appraisal, and appreciative inquiry, ABCD emphasizes internal strengths over external needs. 15,29 ABCD maps local resources and fosters peer support and collaboration with external partners. 15,29 This method builds equal partnerships, leveraging community assets for sustainable, long-term development. 15,29
The community-driven development approach empowers farmers to become the driving force behind their progress.
Local applications of the ABCD approach
Ethiopia
In Ethiopia, ABCD was first piloted in five communities in 2003 by local NGO partners of Oxfam Canada, in collaboration with the Coady International Institute. 8 After training, NGO fieldworkers helped tackle "low hanging fruit" projects. 8 The next stage involved leveraging this organizational capacity to form partnerships with external organizations. 8
"The change in our community is not complete but we are starting to get organized … we sell our grain together through the cereal bank. We have a group of farmers trying a backyard composting system and no longer using chemical fertilizers, and many of us have changed our habits of spending and saving. We diversified our income through gardening and fattening our livestock." - cited in Cunningham (2008)
Western Kenya
A study by Fuchs et al. (2019) explores adoption of climate-smart agriculture practices among farmers in two sites in the Nyando river basin, using the Asset-Based Community-led Development (ABCD) approach as an alternative to the traditional needs-based method. 15
The project increased income for group members and significantly enhanced the resilience of farming systems to climate risks. 15 Additionally, the results demonstrate that ABCD can help external actors support diverse, context-specific, and sustainable livelihoods and landscapes. 15
South Africa
Ikhala Trust is a non-profit organization providing micro-funding to small community-based groups in the Eastern Cape region. 11 It supports initiatives that build on existing community assets, setting its ABCD approach apart from the prevalent needs-based approach in South Africa. 11
The Trust strives to align ABCD with the progressive politics of South Africa, recognizing that many South Africans relied on their own assets and resources during apartheid and took proactive steps to build the mass movement that ended it. 11
Projects and initiatives
What else is already being done to fix the holes of the leaky bucket? Here are some examples of projects and initiatives that try to do just that!
The Global Grand Challenges
Grand Challenges is a series of initiatives that promote innovation to address key global health and development issues. 16 These initiatives issue open calls for grant proposals to tackle specific problems, refining their approach over time. 16 Each challenge acts as an experiment in driving impactful innovation, addressing similar issues from various perspectives, and fostering collaboration across projects for quicker results. 16 Launched in 2003 by the Bill & Melinda Gates Foundation, Grand Challenges in Global Health initially targeted 14 major scientific challenges and awarded 44 grants. 16
Grand Challenges Africa: Accelerating Catalyzing Solutions for Climate Change's Impact on Health and Gender
Climate change endangers global health and development, especially for women and low-income communities. 16 Vulnerable regions face worsened health issues and disrupted healthcare systems, particularly harming women and girls. 16
This GGC initiative sees innovative green technologies and research as essential to reducing greenhouse gas emissions and addressing climate-related health and agricultural challenges in Africa. 16 They strive to empower women as key stakeholders in these innovations. 16
The Climate Investment Funds (CIF)
International programs, such as the Climate Investment Funds (CIF), support climate-smart agriculture and help smallholder farmers in Sub-Saharan Africa overcome barriers like poor equipment and lack of inputs. 7 CIF has invested in 21 countries across the region, from Ethiopia to South Africa, supporting clean technology and climate resilience projects. 7
Examples of impact
Burkina Faso: The project strives to enhance climate change mitigation and poverty reduction through the development of the cashew sector in Burkina Faso. 7 Mozambique: CIF’s Forest Investment Program (FIP) aims to reduce deforestation and forest degradation by 40% by 2030, promoting sustainable rural development and engaging the private sector in forest plantation investments. 7 Ghana: FIP unites public and private sectors with Indigenous groups to restore degraded forests, promote sustainable cocoa and agriculture practices, and secure land tenure rights. 7
The Alliance for a Green Revolution in Africa (AGRA)
AGRA, an African-led institution, focuses on scaling agricultural innovations to improve incomes, livelihoods, and food security for smallholder farmers. 2 In cooperation with governments, NGOs, businesses, and more they set out to provide uniquely African solutions to address the environmental and agricultural challenges farmers face, helping them sustainably boost production and access growing agricultural markets. 2
Their mission is to transform farming from a struggle for survival into a thriving business, recognizing that agricultural transformation is key to moving countries from low to middle income. 2
AGRA's Soil Health Program: Going Beyond Demos
AGRA's Soil Health Program has demonstrated significant success in boosting the adoption of integrated soil fertility management through its "Going Beyond Demos" (GBD) initiative. 2 This initiative focused on several key goals: Increasing the uptake of improved crop varieties and hybrids. 2 Enhancing access to affordable credit, cost-effective storage, and transport services. 2 Improving access to input and output markets. 2 Strengthening farmer groups to operate collectively and influence the agricultural value chain. 2 Providing relevant production, processing, and marketing information to smallholder farmers. 2
Conclusion
Soil health in Sub-Saharan Africa (SSA) is in critical condition due to nutrient depletion. Addressing this issue is essential as the region's population is set to grow significantly, increasing food demand. Smallholder farmers, who are the backbone of SSA's agriculture, face a dilemma between enhancing food security and mitigating greenhouse gas emissions. The use of synthetic fertilizer, for example, can increase productivity and lower variability but is also connected with a significant increase in N 2 O emissions from soils. Integrated approaches such as integrated nutrient management (INM) and the land-water-nutrient-nexus (LWNN) are vital for balancing productivity and environmental impact.
The metaphor of the "leaky bucket" aptly illustrates the multifaceted challenges smallholder farmers face in adopting new technologies. Each barrier, such as limited resources, education, or financial support, represents a hole in the bucket. The lowest hole, or the most significant barrier, determines the overall effectiveness of the implementation process. These elements collectively shape the decisions and ability of smallholders to adopt climate-smart practices and new technologies. Overcoming barriers to technology adoption through community-driven approaches like ABCD can empower farmers and promote sustainable development. Existing projects and policies, such as those by AGRA and CIF, are already working towards these goals. For a sustainable, fair and well-fed future...
Acknowledgement
I would like to extend my sincere gratitude to:
Dr. Henry Neufeldt - Head of Impact Assessment and Adaptation Analysis at the UNEP Copenhagen Climate Centre and Chief Scientific Editor of the UNEP Adaptation Gap Report
for his invaluable contribution to this scientific website. His insights and comprehensive knowledge, generously shared during an expert interview, have significantly enriched the content and accuracy of this site.
References
1 Abdul-Hanan, A. (2017): Determinants of adoption of soil and water and conservation techniques: Evidence from Northern Ghana. In: International Journal of Sustainable Agricultural Management and Informatics Volume 3(1), p. 31-43. DOI: 10.1504/IJSAMI.2017.082918.
2 AGRA (Alliance for a Green Revolution in Africa) (2017): Africa Agriculture Status Report 2014: Climate Change and smallholder agriculture in Sub-Saharan Africa. Nairobi, Kenya: Alliance for a Green Revolution in Africa (AGRA), Issue No. 2. Alliance for a Green Revolution in Africa 123.
3 Asenso-Okyere, K.; Jemaneh, S. (2012): Increasing agricultural Productivity and enhancing food security in Africa: New challenges and opportunities. Washington, DC: International Food Policy Research Institute.
4 Autio, Antti; Johansson, Tino; Motaroki, Lilian; Minoia, Paola; Pellikka, Petri (2021): Constraints for adopting climate-smart agricultural practices among smallholder farmers in Southeast Kenya. In: Agricultural Systems Volume 194, 103284. DOI: 10.1016/j.agsy.2021.103284
5 Bridle, Leah; Magruder, Jeremy; McIntosh, Craig; Suri, Tavneet; et al. (2019): Experimental Insights on the Constraints to Agricultural Technology Adoption. Working Paper, Agricultural Technology Adoption Initiative, J-PAL (MIT) and CEGA (UC Berkeley)
6 Bühmann, C.; Beukes, D.; Turner, D. (2006): Plant nutrient status of soils of the Lusikisiki area, Eastern Cape Province. In: South African Journal of Plant and Soil, 23(2), p. 93–98. DOI: 10.1080/02571862.2006.10634737
7 CIF (Climate Investments Funds) (2024): SUB-SAHARAN AFRICA. Link: https://www.cif.org/country/sub-saharan-africa (29.05.2024)
8 Cunningham, G. (2008): Stimulating asset based and community driven development: Lessons from five communities in Ethiopia. In: Mathie A., Cunningham G., (eds.): From clients to citizens. Practical Action Publishing, p. 261–98. DOI: 10.1080/0961452032000125857
9 de Valença, A. W.; Bake, A. (2016): Micronutrient management for improving harvests, human nutrition, and the environment. Scientific Project, Assigned by Food & Business Knowledge Platform. Wageningen: Wageningen University
10 Dimkpa, Christian; Adzawla, William; Pandey, Renu; Atakora, Williams; Kouame, Anselme; Jemo, Martin; Bindraban, Rem (2023): Fertilizers for food and nutrition security in Sub-Saharan Africa: An overview of soil health implications. In: Front. Soil Sci. - Sec. Soils in Human Health Volume 3. DOI: 10.3389/fsoil.2023.1123931.
11 Eliasov N.; Peters B. (2014): Voices in harmony: Stories of community-driven development in South Africa. Coady International Institute. https://coady.stfx.ca/wp-content/uploads/pdfs/VoicesinHarmony.pdf (Accessed 29.05.2024)
12 Fadeyi, Oluwamayokun Anjorin; Ariyawardana, Anoma; Aziz, Ammar (2022): Factors influencing technology adoption among smallholder farmers: a systematic review in Africa. In: Journal of Agriculture and Rural Development in the Tropics and Subtropics Vol. 123 No. 1., p. 13–30. DOI: 10.17170/kobra-202201195569.
13 FAO (Food and Agriculture Organizations of the United Nations) (2017): Fertilizer trends and outlook to 2020: Summary report. Link: http://www.fao.org/3/a-i6895e.pdf. (Accessed 29.05.2024)
14 FAO (Food and Agriculture Organizations of the United Nations) (2023): OECD‑FAO Agricultural Outlook 2023‑2032. Link: https://www.oecd-ilibrary.org/docserver/08801ab7-en.pdfexpires=1716890556&id=id&accname=ocid54022128&checksum=7C9F29F8F4CE47A2E1AC654D3D3692D7. (Accessed 29.05.2024)
15 Fuchs, Lisa Elena; Orero, Levi; Namoi, Nictor; Neufeldt, Henry (2019): How to Effectively Enhance Sustainable Livelihoods in Smallholder Systems: A Comparative Study from Western Kenya. In: Sustainability, Issue 11, Volume 1564. DOI: 10.3390/su11061564.
16 GGC (Global Grand Challenges) (2024): Grand Challenges Africa: Accelerating Catalyzing Solutions for Climate Change's Impact on Health and Gender. Link: https://gcgh.grandchallenges.org/challenge/grand-challenges-africa-accelerating-catalyzing-solutions-climate-changes-impact-health (29.05.2024)
17 Githunguri, C. M.; Esilaba, A. O. (2014): Appropriate integrated nutrient management and field water harvesting options for maize production mitigating drought in the semiarid southern rangelands of eastern Kenya. International Journal of Agricultural Resources, Governance and Ecology Volume 10, p. 217–226. DOI: 10.1504/IJARGE.2014.064000.
18 IFAD (International Fund for Agricultural Development) (2013): Smallholders, food security and the environment. Rome: International Fund for Agricultural Development, United Nation Environmental Program UNEP. Link: http://www.polity.org.za/attachment.php?aa_id=4478 (29.05.2024)
19 Itabari, J. K.; Nguluu, S. N.; Gichangi, E. M.; Karuku, A. M.; Njiru, E.; Wambua (2004): Managing land and water resources for sustainable crop production in dry areas: A case study of small-scale farms in semi-arid areas of eastern, central and rift valley provinces of Kenya. In L. Crissma (Ed.): Proceedings of Agricultural Research and Development for Sustainable Resource Management and Food Security in Kenya, p. 11–12
20 Kim, Dong-Gill; Grieco, Elisa; Bombelli, Antonio; Hickman, Jonathan; Sanz-Cobena, Alberto (2020): Challenges and opportunities for enhancing food security and greenhouse gas mitigation in smallholder farming in sub-Saharan Africa. A review. In: Food security Volume 13, p. 457-476. DOI: 10.1007/s12571-021-01149-9.
21 Miriti, J. M.; Esilaba, A. O.; Bationo, A.; Cheruiyot, H. K.; Kathuku, A. N.; Wakaba, P. (2011): Water harvesting and integrated nutrient management options for maize–cowpea production in semi-arid eastern Kenya. In: A. Bationo, B. Waswa, J. Okeyo, F. Maina, & J. Kihara (Eds.): Innovations as key to the green revolution in Africa, p. 473–480. Dordrecht: Springer. DOI: 10.1007/978 90-481-2543-2_49.
22 Muluneh, Mitiku Wale; Talema, Getaneh Abebe; Abebe, Koyachew Bitew; Dejen Tsegaw, Belete; Kassaw, Mahider Abere; Teka Mebrat, Aschalew (2022): Determinants of Organic Fertilizers Utilization Among Smallholder Farmers in South Gondar Zone, Ethiopia. In: Environmental health insights 16, 11786302221075448. DOI: 10.1177/11786302221075448.
23 Mutekwa, V.; Kusangaya, S. (2006): Contribution of rain water harvesting technologies to rural livelihoods in Zim babwe: The case of Ngundu ward in Chivi District. In: Water Volume 32(3), p. 437–444.
24 Mutengwa, Charles Samuel; Mnkeni, Pearson; Kondwakwenda, Aleck (2023): Climate-Smart Agriculture and Food Security in Southern Africa: A Review of the Vulnerability of Smallholder Agriculture and Food Security to Climate Change. In: Sustainability Issue 15, Volume 2882. DOI: 10.3390/su15042882
25 Ochieng, J.; Schreinemachers, P.; Ogada, M.; Dinssa, F. F.; Barnos, W.; & Mndiga, H. (2019): Adoption of improved amaranth varieties and good agricultural practices in East Africa. In: Land Use Policy Volume 83, p. 187–194. DOI: 10.1016/j.landusepol.2019.02.002.
26 Oyinbo, O.; Chamberlin, J.; Vanlauwe, B.; Vranken, L.; Kamara, Y. A.; Craufurd, P.; Maertens, M. (2019): Farmers’ preferences for high-input agriculture suppor ted by site-specific extension services: Evidence from a choice experiment in Nigeria. In: Agricultural Systems Volume 173, p. 12-26. DOI: 10.1016/j.agsy.2019.02.003.
27 Raimi, Adekunle; Adeleke, Rasheed; Roopnarain, Ashira (2017): Soil fertility challenges and Biofertiliser as a viable alternative for increasing smallholder farmer crop productivity in sub-Saharan Africa. In: Cogent Food & Agriculture 3 (1), p. 1400933. DOI: 10.1080/23311932.2017.1400933.
28 Riaz, Umair; Mehdi, Shahzada Munawar; Iqbl, Shazia; Khalid, Hafiza Iqra; Qadir, Ayesha Abdul; Anum, Wajiha; Ahmad, Munir; Murtaza, Ghulam (2020): Bio-fertilizers: Eco-Friendly Approach for Plant and Soil Environment. In: Hakeem, K., Bhat, R., Qadri, H. (eds) Bioremediation and Biotechnology, p. 189-213. Springer, Cham. DOI: 10.1007/978-3-030-35691-0_9
29 Sam, M.J.; Fung, H.N. (2022): A Case Study of Technology Adoption through Asset-Based Community-Led Development (ABCD) in a Rice Farming Rural Community – Bario, Sarawak. In: e-Proceedings International Conference on Food and Industrial Crops 2022 (ICFIC 2022), p. 10-13.
30 Sanchez, Pedro (2002): Soil fertility and hunger in Africa. In: Science Volume 195, Issue 5562, p. 2019 - 2020. DOI: 10.1126/science.1065256
31 Senyolo, M. P.; Long, T. B.; Blok, V.; Omta, O. (2018): How the characteristics of innovations impact their adop tion: An exploration of climate-smart agricultural innov ations in South Africa. In: Journal of Cleaner Production Volume 172, p. 3825–3840. DOI: 10.1016/j.jclepro.2017.06.019.
32 Sheahan, M.; Barrett, C.B.(2017): Ten striking facts about agricultural input use in sub-Saharan Africa. In: Food Policy Volume 67, p. 12–25. DOI: 10.1016/j.foodpol.2016.09.010.
33 Simpson, D.; Arneth, A.; Mills, G.; Solberg, S.; Uddling, J. (2014): Ozone—the persistent menace: interactions with N cycle and climate change. In: Current Opinion in Environmental Sustainability Volumes 9–10, p. 9–19. DOI: 10.1016/j.cosust.2014.07.008
34 Tenkorang, F.; Lowenberg-DeBoer, J. (2009): Forecasting long-term global fertilizer demand. In: Nutrient Cycling in Agroecosystems Volume 83, p. 233–247. DOI: 10.1007/s10705-008-9214-y
35 Tittonell, P.; Shepherd, K. D.; Vanlauwe, B.; Giller, K. E. (2008): Unravelling the effects of soil and crop management on maize productivity in smallholder agricultural systems of western Kenya – An application of classification and regression tree analysis. In: Agriculture, Ecosystems & Environment, 123(1–3), p. 137–150. DOI: 10.1016/j.agee.2007.05.005
36 UN DESA (United Nations Department of Economic and Social Affairs), Population Division (2024): World Population Prospects 2022. Link: https://population.un.org/wpp/Graphs/DemographicProfiles/Line/1834 (29.05.2024)
37 Vanlauwe, B.; Coyne, D.; Gockowski, J.; Hauser, S.; Huising, J.; Masso, C., Van Asten, P. (2014): Sustainable intensification and the African smallholder farmer. In: Current Opinion in Environmental Sustainability Volume 8, p. 15–22. DOI: 10.1016/j.cosust.2014.06.001
38 Wu, Wei; Ma, Baoluo (2014): Integrated nutrient management (INM) for sustaining crop productivity and reducing environmental impact: A review. In: Science of the Total Environment 512-513, p. 415-427. DOI: 10.1016/j.scitotenv.2014.12.101
39 Zerssa, Gebeyanesh; Feyssa, Debela; Kim, Dong-Gill; Eichler-Löbermann (2021): Challenges of Smallholder Farming in Ethiopia and Opportunities by Adopting Climate-Smart Agriculture. In: Issue 11, Volume 192. DOI: 10.3390/agriculture11030192.
40 Zhang, F.; Cui, Z.; Fan, M.; Zhang, W.; Chen, X.; Jiang, R. (2011): Integrated soil–crop system management: reducing environmental risk while increasing crop productivity and improving nutrient use efficiency in China. In: Journal of Environmental Quality Volume 40, p. 1051–1057. DOI: https://doi.org/10.2134/jeq2010.0292
41 Zhang, F.; Cui, Z.; Chen, X.; Ju, X.; Shen, J.; Chen, Q.; Liu, X.; Zhang, W.; Mi, G.; Fan, M.; Jiang, R. (2012): Integrated nutrient management for food security and environmental quality in China. In: Advances Agronomy Volume 116, p. 1–40. DOI: 10.1016/B978-0-12-394277-7.00001-4
42 Zougmoré, R.; Jalloh, A.; Tioro, A. (2014): Climate-smart soil water and nutrient management options in semiarid West Africa: A review of evidence and analysis of stone bunds and zaï techniques. In: Agriculture and Food Security Volume 3, Isssue 16. DOI: 10.1186/ 2048-7010-3-16.
