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Phone app set to transform how low-income farmers in Africa invest in fertilizer

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An upgrade to a mobile phone app now offers farmers across Africa even more benefits and cutting-edge fertilizer use technology. This will help farmers to grow healthier, more productive with increasingly profitable crops, as a result of more informed use of how small amounts of fertilizer impact the crops which they grow.

Pilot work on the CABI Fertilizer Optimizer app in Uganda has shown that some farmers realised up to a seven-fold increase in yields. Using funding from the BBSRC Global Challenges Research Fund, the app has now been upgraded to make it easier to use. The new app includes the integrated soil fertility management (ISFM) pratices feature, and a calibration tool which helps farmers to apply the right quantity of fertilizer to their crops.

The Fertilizer Optimizer app is designed to help resource constrained farmers to maximise the return on investment on fertilizer, based on what they can realistically afford.

James Watiti, Coordinator – Development, Communication and Extension at CABI, explained: “The concept behind the CABI Fertilizer Optimizer app is easily transferable to the intermediaries and then to farmers through i training. Farmers think about the crops they wish to grow and what they can afford to spend on fertilizer. The app then makes suggestions about the most profitable way to apply the fertilizer. The Fertilizer Optimizer works even at very low levels of investment and help farmers to get the best possible returns.”

The app was developed using outputs of the research conducted in 13 countries and builds on the linear programming concepts developed by the University of Nebraska-Lincoln, to determine where the crop-nutrient combination generates the most optimal benefits. The tool also ensures that fertilizer recommendations are made within the Integrated Soil Fertility Management framework, further ensuring cost-effectiveness for farmers.

CABI is now rolling out a programme of training for additional extension workers on the use of the Fertilizer Optimization Tools (FOT) with a target to reaching up to 1600 more farmers in Uganda. Across Africa, over 3,000 extension workers have already been empowered to use the FOTs to advise farmers on how to maximise their profits from investments in fertilizers. This is another opportunity to out scale the FOT across Africa.

A social media campaign will also be utilised to help promote the mobile app for FOT across 13 African countries. These are Burkina Faso, Ethiopia, Ghana, Kenya, Malawi, Mali, Mozambique, Niger, Nigeria, Rwanda, Tanzania, Uganda and Zambia.

George Oduor, Global Director Trade and Commodities at CABI, said: “There are over 50 million families living in the rural areas of the 13 countries where we have been exploring how to optimize fertilizer investment based on profit maximization. With the right delivery partnerships in place, all these families can benefit from this work and achieve greater food security and improved livelihoods. This will contribute to the United Nations’ Sustainable Development Agenda 2030 especially Sustainable Development Goal 2: Zero Hunger.”

Additional information

Fertilizer Optimizer App

Download the Fertilizer Optimizer app free of charge from the Google Play Store.

Read more about how the Fertilizer approach could empower 50 million African families

Learn more about the Fertlizer Optimization Tool, including videos on how it works, from the Africa Soil Health Consortium website


CABI published two blogs ‘from the field’ showcasing how the Fertilizer Optimization Tool is benefiting farmers – ‘Fertilizer Optimization Tool pays dividends for farmers in Uganda’ and ‘Fertilizer Optimization Tool helps son to teacher training school’.

Project funders

The original conceptualization and development of the optimization tool was by the university of Nebraska-Lincoln. Jansen J, Wortmann CS, Stockton MC, Kaizzi CK (2013). Maximizing net returns to financially constrained fertilizer use. Agronomy Journal 105 (3) 573-578

The Fertilizer Optimizer tool was built as part of the Optimising Fertilizer Recommendations in Africa (OFRA) project, led by CABI. The project was a partnership between CABI, the University of Nebraska Lincoln, national governments and agricultural research and extension systems in 13 countries in sub-Saharan Africa. OFRA was supported by the Alliance for a Green Revolution in Africa (AGRA). The development of the original tool into an App was supported by the BBSRC Global Challenges Research Fund (BBS/OS/GC/000014B) through a partnership with Rothamsted Research, the Centre for Ecology & Hydrology, QED and ICRAF. Version 2 was supported by a second round of funding from the BBSRC Global Challenges Research Fund (BBS/OS/GC/200014A) through a partnership with Rothamsted Research, the Centre for Ecology & Hydrology and QED.

Project partners

About the Centre for Ecology & Hydrology

The Centre for Ecology & Hydrology (CEH) is a centre of excellence for integrated research into land and freshwater ecosystems and their interaction with the atmosphere. CEH is a Natural Environment Research Council (NERC) research institute, part of UK Research and Innovation (UKRI). The Centre’s independent, impartial science addresses major societal and environmental challenges: how to protect and enhance the environment and the benefits it provides; how to build resilience to environmental hazards; and how to manage environmental change. Its core expertise is in environmental monitoring, measuring and modelling.

About QED

QED builds technology solutions for basic problems. Basic problems have been forgotten. But the developing world helps us remember them. They are problems most fundamental to the human condition.  Environmental security, food security, health security … matters of life and death.  We search for worthy problems, and help our partners pursue their solutions.  And we infuse our solutions with “the hacker spirit” — the essence of computer science, math, and art.

About Rothamsted Research

Rothamsted Research is the longest-running agricultural research institute in the world. We work from gene to field with a proud history of ground-breaking discoveries, from crop treatment to crop protection, from statistical interpretation to soils management. Our founders, in 1843, were the pioneers of modern agriculture, and we are known for our imaginative science and our collaborative influence on fresh thinking and farming practices.

Through independent science and innovation, we make significant contributions to improving agri-food systems in the UK and internationally. In terms of the institute’s economic contribution, the cumulative impact of our work in the UK was calculated to exceed £3000 million a year in 20151. Our strength lies in our systems approach, which combines science and strategic research, interdisciplinary teams and partnerships.

Rothamsted is also home to three unique resources. These National Capabilities are open to researchers from all over the world: The Long-Term Experiments, Rothamsted Insect Survey and the North Wyke Farm Platform.

We are strategically funded by the Biotechnology and Biological Sciences Research Council (BBSRC), with additional support from other national and international funding streams, and from industry. We are also supported by the Lawes Agricultural Trust (LAT).

For more information, visit; Twitter @Rothamsted


The Biotechnology and Biological Sciences Research Council is part of UK Research and Innovation, a non-departmental public body funded by a grant-in-aid from the UK government.

BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.

Funded by government, BBSRC invested £469 million in world-class bioscience in 2016-17. We support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.

More information about BBSRC, our science and our impact.

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