Guy Kirk, Professor of Soil Systems at Cranfield University, is leading a £1 million research project to overcome a soil health problem affecting rice production in sub-Saharan Africa.

Rice is a major staple food across sub-Saharan Africa and demand for it is increasing rapidly with urbanisation and changes in consumer preferences. Domestic production accounts for only 60% of the rice consumed which means there is a heavy reliance on imports - the import of rice into sub-Saharan Africa accounts for a third of the global rice trade. There is therefore mounting pressure to greatly increase sub-Saharan rice production.

One of the main barriers to increasing production is the soil disorder known as iron toxicity. This is a particular problem in flooded paddy soils, and particularly the highly weathered and nutrient-depleted soils that typify sub-Saharan Africa. In affected areas, rice yields are reduced by up to 90%. Traditional, indigenous African rice varieties can tolerate the toxicity, but are low yielding. That means large areas of land are needed to meet the demand for more rice, and this is driving unsustainable development of new lands, typically in fragile wetlands in inland valleys to the cost of biodiversity and other vital ecosystem services.

The Cranfield-led study will examine the traits that allow indigenous African rice varieties to tolerate the toxicity, with the aim of incorporating these traits into more high-yielding varieties through plant breeding. It will also seek to map areas where new rice varieties and crop management to tackle iron toxicity will be most beneficial. The project will use a combination of soil chemistry, plant physiology and molecular genetics, in partnership with plant breeders and agronomists based in West Africa and Madagascar.

Professor Kirk said: “There is widespread recognition of the need to increase sub-Saharan rice production to meet projected increases in demand for rice. Less than 10% of the total inland valley area in sub-Saharan Africa could be sufficient to meet the demand for rice in Africa if we can overcome iron toxicity. But currently, increased production with low-yielding varieties and poor management is destroying large swathes of natural ecosystems in inward valleys. With realistic improvements in varieties and management, we can greatly reduce the amount of land needed and therefore safeguard the vital biodiversity of the African inward valleys.”

Partners in the three-year study include AfricaRice, the University of Antananarivo and the Japan International Research Center for Agricultural Sciences. Funding for the project comes from BBSRC, part of UK Research and Innovation, through the Global Challenges Research Fund.

Announcing the funding for the project as part of its Sustainable Agriculture for Sub-Saharan Africa programme, Professor Sir Mark Walport, Chief Executive of UK Research and Innovation, said: “Stresses such as drought, and the restriction of vital resources including nutrients and water are among the challenges affecting the development of sustainable agriculture in Sub-Saharan Africa.

“By bringing together UK researchers with partners in the region, these projects will play an important role in addressing these challenges and unlocking the potential of sustainable agriculture to transform food production and improve lives.”

Notes for editors

Iron toxicity is a set of severely yield-limiting disorders associated with high concentrations of reduced ferrous iron (Fe(II)) in flooded paddy soils. It is exclusively a problem of paddy rice, linked to the biogeochemistry of flooded, anaerobic soil. It is a particular problem in African rice systems because of the nature of the soils, which are highly weathered, nutrient-depleted and rich in Fe oxides, in contrast to the young alluvial rice soils of the Asian lowlands. It affects a large part of the existing and potential rice area in sub-Saharan Africa (SSA) (estimates vary from 20-60% of the area) and causes large yield losses (up to 90%). There are currently efforts to exploit tolerance of it in the indigenous African rice germplasm in breeding and management programmes at AfricaRice and elsewhere. But this is constrained by the complexity of the disorder and by poor understanding of the underlying mechanisms and genetics of tolerance, which reflects its relative unimportance in Asian rice systems where most rice research has been focused.

In this project we aim to (a) elucidate the mechanisms and genetics of tolerance to Fe toxicity in indigenous African germplasm, in support of rice breeding and management programmes, and (b) assess the potential of improved germplasm and management to raise the productivity of existing and new rice-based farming systems across SSA. We will especially focus on Oryza glaberrima (‘African’ rice) species, indigenous to West Africa, and sub-species of Oryza sativa (‘Asian’ rice) particular to Madagascar. We will use a combination of soil chemistry, plant physiology and molecular genetics approaches with field work in West Africa and Madagascar, supported by controlled-environment and laboratory work at Cranfield. We will also map the spatial extent of different types of Fe toxicity in existing and potential rice areas across SSA, and we will develop GIS tools for assessing the potential for improved germplasm and nutrient and water management to raise the productivity of rice-based farming systems in these areas.

About the Global Challenges Research Fund 

The Global Challenges Research Fund (GCRF) is a £1.5 billion fund announced by the UK government in late 2015 to support cutting-edge research that addresses the challenges faced by developing countries.

Alongside the other GCRF delivery partners, BBSRC is creating complementary programmes that:

  • Promote challenge-led disciplinary and interdisciplinary research, including the participation of researchers who may not previously have considered the applicability of their work to development issues
  • Strengthen capacity for research, innovation and knowledge exchange in the UK and developing countries through partnership with excellent UK research and researchers
  • Provide an agile response to emergencies where there is an urgent research need.

GCRF is part of the government’s commitment to allocate 0.7% of the UK’s Gross National Income to Official Development Assistance (ODA) for promoting the welfare and economic development of developing countries. As well as being scientifically excellent, research supported by GCRF must meet the criteria for classification of expenditure as ODA. For further information see: UK Research and Innovation: Global Challenges Research Fund


The Biotechnology and Biological Sciences Research Council (BBSRC) 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 £498 million in world-class bioscience in 2017-18. 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.

rice head in a field
Rice field

About Cranfield University

Cranfield University is a specialist postgraduate university that is a global leader for education and transformational research in technology and management.

Agrifood at Cranfield

Agrifood has been a key strategic theme at Cranfield University for over 40 years. We have internationally recognised expertise across both domestic and international food supply chains from primary food production, inputs - soil, plants and water, through to point of sale, waste reduction and applied informatics.

Students work closely with our partners in industry, Government or the NGO sector. We understand our clients’ challenges because more than 80% of the University’s business comes from sources other than Government. Most of our academic staff have spent considerable portions of their career in industry or Government, and are especially solution-oriented. We delight in assembling pan-University teams of experts from across our skill sets, often in collaboration with other Universities, and consultants, to meet challenges that fall outside the conventional academic disciplines.