Soil Science and Smallholders: How Can Better Knowledge of Soils Contribute to Sustainable Agriculture in Africa?
Lessons from ten years of sampling, modelling and mapping the soils of Africa, and the importance of this research for the farmers that make their livelihoods from it.
Written by Alexander Wowra
To celebrate the launch of iSDAsoil, an open access soil information tool for Africa, researchers associated with the social enterprise iSDA met for a roundtable discussion.
Hundreds of millions of smallholder farmers in Africa produce some of the world’s most prized commodities, such as coffee and cacao. However, many of these farmers lack basic information that would allow them to make sustainable farming decisions that improve their yields and profitability. One of the most important yield-limiting factors is a lack of information about the soil.
We reflect upon the recent history of soil mapping efforts in Africa, its importance for smallholder farmers, and what the future holds for this critically important, but often overlooked resource.
The importance of soil research
“Soil retains and supplies water and nutrients for plant growth, is a critical transformer in major global nutrient cycles, such as carbon, nitrogen and phosphorus, and decomposes and filters waste and pollutants”, Keith Shepherd of iSDA/ICRAF opened the discussion.
His sentiment touched on a major benefit of farming practices that prioritise soil health: their potential to contribute to the health of the planet.
What’s more, carbon capture capacities increase when soil health is improved, which in turn can reduce emissions and mitigate some of the effects of climate change. The WBCSD report described an “urgent need to mobilise nature-based solutions to address the challenges of climate change”.
Global soils serve as sinks for terrestrial carbon and gases that would otherwise increase temperatures in the atmosphere. Soils contain two to three times more carbon than the atmosphere, the World Business Council for Sustainable Development (WBCSD) found in a 2018 report.
“Soil is fundamental to life, yet for a long time, soil information in Africa has been incomplete and inadequate for proper agricultural and scientific use”
— Francis Tetteh, Ghana Soil Information Service (GhaSIS)
Indeed, knowing soil status is key to designing strategies to sustainably intensify agriculture.
“In order for this informed decision-making process to work, it needs to involve researchers, development actors, policy makers, as well as the private sector and — of course — the farmers,” agreed the Ethiopia Soil Science Information System’s (EthioSIS) Tegbaru Bellete Gobezie.
Often, the available soil data is outdated or too broad in terms of geographic location, thus rendering it useless for large and small scale farmers as well as scientists.
For these reasons, iSDA and partners developed “iSDAsoil”, a soil and agronomy information service aimed at delivering farm level data for the entire African continent, at a high resolution of 30m (roughly 24 billion locations across Africa). iSDAsoil builds upon previous work of the Africa Soil Information Services (AfSIS) project, which organised the collection and analysis of over 50,000 soil samples from across Africa.
“This detailed map is able to show variability in more than 10 distinct soil factors to assist farmers in developing tailored soil management strategies” Tegbaru added.
He continued, “In contrast to related initiatives, fertility capability classifications and agronomy information have now been integrated with the physio-chemical characteristics of the soils in Africa, which will definitely help all actors to do the right things right”.
Roundtable panelists working for the soil information systems of Ghana, Tanzania, Ethiopia, and Nigeria all indicated there is high demand for sustainable soil information in the private sector, especially from the fertiliser industry, which requires soil information to inform the type of fertiliser to manufacture.
High spatial resolution data: the holy grail of farm-level agronomy
Soil is a complex and highly variable medium, and traditionally soil science research has been challenged in generalising solutions and management: recommendations that work in one location may not work in another, Keith Shepherd pointed out. Improved resolution soil information is one tool that we can use to understand these differences.
Whether practiced at a smallholder or a large industrial scale, “all farming is essentially an exercise in risk management”, explained Bob MacMillan of OpenGeoHub.
Macmillan continued, “When farmers are presented with soil information that does not match their personal understanding of observable variations in soil within their plots, they are not likely to put much trust in it, and are unlikely to make use of it to inform their management.”
Therefore, precision agriculture, or “farming per pixel” has increasingly become the norm in intensive agriculture. In precision farming, management practices and inputs are varied in space and time, for example in response to differences in soil properties and changes in meteorological conditions.
This is where the need for high spatial resolution soil data comes in. Finer resolution soil information effectively captures the variation observable at a local or field level and therefore farmers are more likely to trust it.
EnvirometriX’s Tom Hengl even went as far as depicting spatial resolution as “probably the most important aspect of modern soil information, especially for small-scale farmers.”
He highlighted the limitations of previously created coarser resolution maps (e.g. Vagen et al, 2016; Hengl et al. 2017) in capturing the realities on the ground. These maps at 250 m or 1 km resolution do not match the size of smallholder fields which are often smaller and have mixed land use.
This is a very important issue since more than 475 million out of 570 million farms in the world are smaller than 2 hectares. However, only “a tiny fraction of the [research] literature” focuses on smallholders, according to an October 2020 Nature article that cited research from the Ceres2030 project.
“The majority of the agricultural research publications assessed were unable to provide solutions, particularly to the challenges faced by smallholder farmers and their families,” the article stated.
Hengl observed that mapping at resolutions of 30 m and below is an essential foundation on which to identify problems at the farm level. By properly reflecting soil information at this level of detail, farmers and other stakeholders can now finally make efficient use of the information in their decision-making process.
Achim Dobermann, chief scientist at the International Fertilizer Association (IFA), suggested that breakthroughs in sustainable agriculture will need to come “from the interpretation side” — now that we have the data, the challenge will be how to interpret it to make the correct farming decisions.
“If we can have more reliable semi-automatic interpretation streams and models that lead to more direct decision-making, that makes a big difference”
— Achim Dobermann, IFA
“Now that we have mapped the soil properties at 30m can we truly say that this information is ready for farm-scale decisions”, concluded Hengl.
Translating scientific results into actionable gains on the ground
But specifically how can information such as that provided by iSDAsoil best benefit smallholder farmers? The overarching consensus among iSDA panelists was that iSDAsoil will serve as a starting point upon which to build and improve local knowledge, local products and local solutions.
“The next frontier is to find out how iSDAsoil’s data can be used to increase productivity and profitability of African farmers”, said Stephan Haefele of Rothamsted Research.
First however, the newly-gained insight will need to be repackaged into technologies and information the farmers can understand and adopt, emphasised Tetteh.
Tetteh continued, “The ideal case would be if local businesses would develop creative commercial B2B solutions that build upon primary data”.
For example, small and medium-sized enterprises and startups could connect agrochemical suppliers and small scale farmers through mobile phone apps or similar (read more on importance of smallholders being involved in macro- and micro-land use planning).
Tegbaru drew on his personal experience in working at the Ethiopian Agricultural Transformation Agency (ATA) to complement this vision of linking iSDAsoil with well established and proven systems to reach millions of small scale farmers.
“Integrating the agronomic advice and information with Voice Response/ Short Message Service (IVR/SMS) systems would be one option. Farmers can call a toll-free hotline on 8082 and access information in five different local Ethiopian languages,” said Tegbaru.
Under ATA, the collected data also plays a critical role in supporting policy makers and agricultural practitioners in devising investment strategies, input (seeds, fertilisers, etc.) procurements and distribution schemes, he said.
Vincent Aduramigba of Nigeria Soil Information Services (NiSIS) agreed, stressing the need for development and generation of demand-driven tools that are technologically suitable, economically viable, and socially acceptable for resource constrained smallholder farmers in Africa.
He pointed to developments in his own country, Nigeria, where a national agricultural promotion policy (APP) has been implemented to link soil technologies to integrated farming systems and to help smallholder farmers achieve economic and environmental sustainability in producing field crops.
MacMillan seconded the view that legislation such as the one in Nigeria could be useful to trigger technological and agronomic best-practices adoption among local farmers. However, he also urged private businesses collaboration to focus on early adopters within the local farming community.
If those farmers who first use the newly developed insights and technology receive demonstratively better results, mass adoption will ensue.
However, MacMillan cautioned that “In our experience, even if productivity is clearly increased in five years out of seven, farmers were still very concerned about the two years with poor yields and were often reluctant to take on any risks involved in changing their management practices.”
This highlights why farmers need a holistic approach in order to reduce chances of loss — soil information can help to improve productivity, but farmers also need tools to help them address non-soil related limits to farm profitability, such as distribution of produce and access to finance. Indeed, iSDA’s strategy is to develop advisory tools that lead to a sustainable increase in profitability, rather than just on the good years.
The need for data sharing in agriculture
There have been numerous large-scale research projects that have aimed to improve crop yields in Africa, however data from such projects is not always easy to access, especially after the research concludes. In contrast, iSDAsoil has been designed as an open access, rapidly updatable resource to encourage data contribution, which will in turn progressively improve the accuracy of African soil data.
There is growing recognition that a metric for research success should be how usable the outputs are: “A connection between data generators and the further analyses of the data sets they share could provide funders with new means for assessing the impact of their grant awards”, Heather H. Pierce and colleagues argue in their Nature article.
MacMillan underscored the importance of advertising data contributions in publications and distributions of derived products.
“We must create a two-way street where contributors obtain value by means of increased opportunities for them to process or add value to any data they contribute, as well as to any combined open data”, he said.
While Vincent Aduramigba and MacMillan cautioned that strong commitment based on trust and benefit to all stakeholders are prerequisites to the success of open data exchange, Tegbaru expressed confidence that this was the right time to design feasible approaches for data sharing under the overarching FAIR data principles.
“What motivates data holders to share their data… ? Would it be possible to make soil data capture citizen science, in a standardised way?” he asked.
Concluding, MacMillan described iSDAsoil’s potential as “an extended and continuous crowd sourced agronomic field trial that can be data mined to uncover successful agricultural practices and methods at local to farm scales.”
This is where several participants of the roundtable saw powerful potential: iSDAsoil’s capacity to encourage data sharing, standardisation of data collection, and collaboration mechanisms.
Continued innovation is key to improving soil analysis
Africa has recently been in the forefront of implementing new innovative strategies and technologies that advance sustainable agricultural practices.
This is especially true when it comes to technology for collecting soil samples in the field, analysis using new spectral and other analytical equipment and converting this new data into actionable spatial information products.
The panelists mentioned infrared spectroscopy as one of the most meaningful innovations in soil science and agronomy research over the last decade. This method uses infrared light to determine the chemical composition of the soil.
Infrared spectroscopy can analyse a large number of samples with minimal preparation, and has accelerated soil sampling and analysis significantly: “With the use of infrared spectroscopy by AfSIS, the long soil analytical processes and high cost of laboratory reagents are becoming things of the past”, explained Tetteh.
MacMillan further noted recent advancements in extending soil analysis to consider and measure microbiological diversity as a measure of ecological health. Many farming practices reduce soil biological diversity, removing more nutrients than are put back, which ultimately damages the long term health of soils.
Meanwhile, increasingly fine-tuned systematic soil sampling schemes will concentrate on new sampling locations that will help most to reduce error.
In the words of Tanzania Soil Information Services’ (TanSIS) Dr. Joel Meliyo: “It is equally important that the very productive areas whose data may not be in the database — such as irrigated valleys — are now the focus for sampling and data generation.” This highlights an important point: “If we are able to collect samples from a variety of different soil types and landscapes, the maps that we generate are likely to be more accurate,” concluded Matt Miller from iSDA.
Encouraging the adoption of new technologies
So what remains is the challenge of convincing governmental and international bodies to support the necessary initiatives, as well as support new projects to combine their data to continuously improve the precision and accuracy of iSDAsoil.
Often, research results are not perfectly aligned with government policy, which initially makes it difficult for governments to buy into and promote those results. So how do you convince the government to adjust its stance?
“Sometimes things can be technically correct, but they also need to be policy-fit. So this process should not only be an academic exercise but also political”
— Vincent Aduramigba, Nigeria Soil Information Service (NiSIS)
Invoking his previous experience at NiSIS, he continued: “If the soil is improved and we are able to have specialised fertiliser for our crops, the government can look at the results and see how it benefits them as well.”
He cited his work in Nigeria as proof that it is possible to demonstrate to the government through small pilot projects the need for a change in approach. Adjustments such as collecting geo-referenced soil samples allowed the development of a special fertiliser for cocoa, which encouraged agribusiness development. Once government officials understood this, they adjusted their policy and asked local farmers to buy into it too.
Further elaborating on this concept in which research outputs of projects are executed in conjunction with local institutions and local farmers, Meliyo outlined several steps crucial to seeking adoption as an end goal:
- Prepare the proven technologies that deserve dissemination and institutionalise them as services or technologies via private sector actors.
- Package the outputs into simple usable products targeting different clients.
- Create awareness via different pathways such as a variety of media outlets or the use of handset apps.
Government intervention to support these kinds of pilot projects leads to the widespread adoption of technologies in the agribusiness sector and is a common practice.
The problem is that many government-backed projects rely on subsidies, and there remains no long term financial sustainability, without continued financial investment according to Tetteh.
Reflecting on the role of Africa’s nimble and entrepreneurial private sector in last mile delivery, MacMillan said: “If it is profitable and feasible to deliver and it is effective and profitable for the farmer to use, it will survive and prosper.”
This is why rather than subsidy-driven approaches, iSDA focuses on end-to-end solutions in partnership with suitably aligned agribusinesses, focused on smallholder value chains.
“Adoption of new technologies by farmers in Africa will bring about the desired change in perception of workable, sustainable technologies. When farmers appreciate that research can improve productivity of their farms, then there will be sustainable agriculture in Africa”
— Joel Meliyo, TanSIS
To learn more about iSDAsoil, please visit https://isda-africa.com/isdasoil
