Knowledge for a sustainable world

BSc (Hons), PGCE, MSc, PhD
Dr Tanya E Stathers
Associate Professor of Sustainable Agri-food Systems; Postharvest specialist

Food and Markets Department

Natural Resources Institute, Faculty of Engineering & Science

+44 (0)1634 88 3626

Dr Tanya Stathers joined the Natural Resources Institute (NRI) of the University of Greenwich in 1998. Prior to this she had worked in Papua New Guinea as a researcher at the Cocoa and Coconut Research Institute (1997-98), and at Naliendele Agricultural Research Institute in Mtwara, southern Tanzania on the ODA-funded Cashew Research Programme (1993-95)

Tanya’s research has covered a broad-range of topics related to smallholder agri-food systems across sub-Saharan Africa (SSA). These have included: a particular focus on postharvest systems and the reduction of and understanding of postharvest losses (including their nutritional and financial value) in staple grains and roots and tuber crops; multi-stakeholder learning processes; agricultural adaptation to climatic and other changes; creative training materials and approaches; rural-urban interdependencies and gender and diversity aspects of agri-food systems; and poverty impacts of market standards such as Rainforest Alliance and Fairtrade in tea.

Tanya's earlier work focused on: the development of pre and postharvest integrated pest management options for a range of smallholder produced cash and food crops; including grain storage treatments, use of farmer field school approach, cultural control methods, entomopathogenic fungi, pheromones, natural enemies and resistant cultivars.

She is currently co-supervising four postgraduate students working on the role of postharvest loss reduction in building climate change resilience; and recently supervised a postgraduate student on drivers of food choice in a deprived area of UK. She has developed and taught a number of training courses at a range of different levels.

She has significant field work experience in Tanzania, Kenya, Malawi, Uganda, Zimbabwe and Papua New Guinea and has also worked in Ethiopia, Rwanda, and South Africa. She also speaks Swahili and slightly rusty French.

Keywords: Ag4D, agriculture, postharvest, postharvest losses, PHL, Sub-Saharan Africa, climate change adaptation, experiential learning processes, agricultural innovation systems

Every year after harvest, USD$ 4 billion worth of cereal grains alone are lost across Sub-Saharan Africa, this is valuable food that could have fed millions of people and driven economic activity in the region. Much of Tanya’s >25 years of research within agricultural innovation systems across sub-Saharan Africa has focused on the participatory development and promotion of knowledge and effective and acceptable technologies that can help in reducing these postharvest losses, and particularly storage losses. She is also involved in more accurately quantifying what losses are happening at each postharvest stage in different crops and why, and what these mean financially and nutritionally for countries; to help shape more targeted loss reduction investments.

Realising the importance of experiential learning approaches in building capacity, she has co-developed a number of practical training courses, manuals and other supporting materials for trainers and farmers. Amongst these are the WFP ‘Training Manual for Improving Grain Postharvest Handling and Storage’, the Moyo Nuts/ New Rotations Zambia ‘Improving Groundnut Production and Postharvest Handling and Storage’ and the Reaching Agents of Change ‘Everything you ever wanted to know about sweetpotato’.

Tanya has developed and written several research-based training manuals, and created accompanying experiential-learning training courses and appropriate tools including sets of visual flip-charts to facilitate field-based agriculture training and cartoon handouts. These combine technical elements of agricultural topics with a hands-on-learning approach. Examples include:

The ‘Everything you ever wanted to know about sweetpotato’ training-of-trainers’ manual and course she developed for the Reaching Agents of Change programme. The manual was translated into French, Portuguese and Kiswahili and is used in >11 countries, and the course is run-for-profit by training institutes in Ghana, Nigeria, Burkina Faso, Mozambique, and Tanzania.

The ‘Training Manual and Course on Improving Grain Postharvest Handling and Storage’ she co-developed for the World Food Programme (WFP) with Rick Hodges, is widely-used in >21 countries for training groups of smallholder-farmers to improve the quality of their produce through better postharvest management enabling them to gain access to higher value quality-sensitive markets.

The ‘Improving Groundnut Production and Postharvest Handling and Storage’ manual, course, field charts and farmer handouts developed to assist two private-companies in Malawi and Zambia in building farmers’ capacity to access higher quality aflatoxin-free groundnut markets.

In 2017, as part of a scaling initiative she worked with a CIP team and developed trainers’ guides, farmer handouts and field charts on sweetpotato planting material conservation ‘Triple S (sand, storage, sprouting)’ enabling farmers to produce sweetpotato planting materials prior to the rain season; thus providing food during the hungry season, climate-resilience and extra income. These tools have been used to train service providers in nine African countries, who have used them to train >7,500 farmers to date.

During the last five years she also co-supervised five postgraduate students registered at the University of Zimbabwe. She lectures and provides practical training on Postharvest Entomology in a taught Masters programme. She led the creation and delivery of a short training course on ‘Agricultural adaptation to climate change’ for >40 university lecturers and postgraduate students from Ethiopia and Uganda during the Biofarming initiative.

She was also involved in developing one of UoG’s earliest e-distance learning MSc programmes on Grain Storage Management in 2000.

Expanding the African Postharvest Losses Information System – APHLIS+

Dates: 2016-2020

Partners: EC Joint Research Council, Agricultural Knowledge Management Services, University of Zimbabwe, network members in 37 Sub-Saharan African countries

Donor: Bill and Melinda Gates Foundation

The 2008 food crisis caused development agencies involved in improving food security across sub-Saharan Africa to realise they needed a more detailed and accurate understanding of the level of postharvest loss of staple food crops occurring

The African Postharvest Losses Information System (APHLIS) was developed and launched in 2009, to bring a rigorous knowledge management approach to cereal postharvest losses (PHL). Tanya leads two work packages: i) to expand the approach to other key staple food crops (i.e. cowpeas, common beans, groundnuts, cassava), and ii) to widen the focus from weight losses by converting these into financial and nutritional values to increase understanding, and to additionally consider the impacts of postharvest losses in quality. The results of these work packages will be available online by end of 2019.

Addressing postharvest bottlenecks: what role for solar powered storage of fresh sweetpotato roots in sub-Saharan Africa? – an integral part of the Sweetpotato Action for Security and Health in Africa (SASHA II) project

Dates: 2015-2019

Partners: International Potato Centre (CIP), Organi Ltd.

Donor: Bill and Melinda Gates Foundation

Africa is rapidly urbanising. Fresh sweetpotato roots are already an important part of urban diets in many countries. Exciting new initiatives include the use of orange-fleshed sweetpotato (OFSP) puree in bread recipes by major supermarket chains in Kenya, helping to provide vital Vitamin A in the diets of the rapidly growing urban population. However, a year-round supply of fresh sweetpotato roots and sweetpotato products is required to meet these urban consumers’ demands; this can be achieved either through constant year-round production and supply of fresh roots or through a combination of staggered production and the storage of fresh OFSP roots to cover periods of low supply.

One of the objectives of the Sweetpotato Action for Security and Health in Africa (SASHA II) project is to investigate whether commercial-scale storage of fresh OFSP roots is feasible.

To better understand whether fresh root storage might offer opportunities within this OFSP supply chain, in 2015 Tanya undertook a detailed value chain study involving 59 stakeholder and focus group interviews across eight focal counties in Kenya to understand existing sweetpotato value chains, their seasonality, farmers’ production trends and constraints, traders’ root sourcing and trading patterns, price dynamics, retailing behaviours, and consumers’ preferences. This found that large quantities of yellow-fleshed sweetpotato roots are traded from Kabondo and Migori to the large urban markets in Kisumu, Nakuru and Nairobi, with traders sequentially purchasing roots from different areas during the year in order to smooth the supply. Prices vary between the peak and low supply seasons by up to 70%, suggesting that storage has the potential to reduce cost to the consumer. Only very limited amounts of OFSP are currently grown in these counties. The findings of this study were combined with different OFSP puree and fresh root requirement scenarios to calculate the storage capacity needed for a puree processor to hold at least one month’s stock of OFSP roots to control and smooth their supply chain, and reduce the impact of price rises during the low season. Based on this, a medium scale (10 - 30 tonnes) fresh root storage facility was constructed at the processor’s site in Homa Bay (see summary brief).

Tanya has then designed and together with the Organi Ltd and CIP team run a series of fresh OFSP root storage trials in three different storage facilities (2016-2019) at the Organi Ltd in western Kenya. These trials have compared the storage characteristics of different OFSP varieties, and different pre-postharvest handling and curing practices on stored root quality during 4 months storage (see summary briefs 2016, 2017, 2018).

To better understand demand for OFSP fresh roots amongst urban consumers, Tanya has worked with the CIP team in designing and leading a study of consumer awareness of, demand for and packaging of vitamin A rich OFSP roots in informal markets and high-end grocery stores in Nairobi (2018).

Supporting smallholder farmers in southern Africa to better manage climate-related risks to crop production and postharvest handling

Dates: 2013-2016

Partners: University of Zimbabwe, Chitedze Agricultural Research Services Malawi, Food and Agriculture Organisation, University of Pretoria, FANRPAN, SOFESCA, University of Wageningen

Donor: European Union

Southern Africa is prone to extreme weather events, such as drought, floods and tropical cyclones, which have devastating impacts on human health, agriculture, infrastructure and other key socio-economic sectors. These climate-related shocks severely affect the livelihoods of the region’s population; 75% of who depend on predominantly rain-fed agriculture. Climate change, with projected increases in the incidence and intensity of extreme climatic events, is likely to exacerbate existing vulnerabilities.

This project aimed to i) develop and promote innovative techniques, methods and approaches for smallholder farmers to manage risks to crop production and postharvest handling associated with drought, floods and cyclones, and ii) strengthen regional knowledge and institutional arrangements on risk management for crop production and postharvest handling in areas prone to climatic hazards.

Tanya was involved in the design and implementation of community-profiling surveys in southern Malawi and Hwedza and Mbire districts of Zimbabwe in 2013 and 2014, which sought to understand farmers and key stakeholders’ experiences and perspectives on the impacts of and coping strategies for climate-related risks and longer-term adaptation options.

This shaped the development of the activities for building postharvest capacity of key agricultural service providers and actors; and learning alliances for community testing of different stored grain (sorghum, maize, cowpeas) treatment options which Tanya has been involved in.

Development of a post-harvest handling and storage handbook and training approach for the World Food Programme’s (WFP), Purchase for Progress (P4P) programme

Dates: 2011-2013

Donor: Bill and Melinda Gates Foundation

Background: WFP aims to purchase food from areas close to where relief food is needed. Over 950 Farmers’ Organisations (FOs) in 20 developing countries are registered to supply grain to WFP through the P4P programme for local food aid procurement. Many of these FOs struggle to supply WFP with cereals and beans that meet quality and safety standards. To help them meet quality standards, FOs are trained in postharvest handling and storage (PHHS).

Objectives: To develop a comprehensive set of Postharvest Handling and Storage training materials and to help ensure a common basis based on best practice for PHHS training efforts within WFP’s Purchase for Progress (P4P) programme. This will enable FOs to collect, store and supply better quality grain to WFP.

Results: The ‘Training Manual for Improving Grain Postharvest Handling and Storage’ can be viewed online. 4,000 copies have been printed in English for distribution to the trainers in the Anglophone P4P focal countries, and 2,000 copies in French. The manual includes technical PHHS information for improving household, primary aggregation point and warehouse level PHHS, it includes ~200 cartoons and 6 posters for farmer training which are designed so the text can be added in the relevant vernacular language, it also includes a detailed section on ‘How to deliver training on PHHS’ using an experiential learning approach.

NRI’s Dr Stathers and Prof Hodges analysed the existing training materials, conducted a detailed needs assessment with key players in 3 focal P4P countries, designed, wrote and developed the manual and approach. They along with colleagues also created the text underlying the World Bank’s 2011 ‘Missing Food’ report which proposes an approach to reducing cereal postharvest losses in Sub-Saharan Africa – this builds on their long and detailed field experiences of smallholder postharvest systems.

Exploring rural-urban interdependence and the impact of climate change on interdependent food and agricultural systems in Tanzania and Malawi

Dates: 2009-2012

Partners: Institute of Resource Assessment University of Dar es Salaam, Chancellor College University of Malawi, ARI Hombolo Tanzania, ARI Uyole Tanzania, INADES Formation Tanzania, Bvumbwe ARI Malawi

Donor: FCDO (previously DFID) and IDRC

Background: Africa is rapidly urbanizing. By 2030 there are projected to be over 759 million African urban dwellers. This poses major challenges for the further provision of infrastructure and services. Alongside this, Africa is particularly vulnerable to climate change and climate variability (CC&CV). As urbanisation and inequality increase, more sophisticated analyses of the linkages and interdependencies between rural and urban areas are emerging. Flows of products, people, knowledge and information, natural resources and money provide strong and dynamic linkages.

Objectives: This research project funded by IDRC and FCDO aimed to strengthen the capacity of individuals, organizations and systems within the agriculture and food innovation systems connecting rural and urban communities in Tanzania and Malawi to adapt to the challenges and opportunities arising from CC&CV.

Results: The project used a multi-stakeholder participatory action research process to explore Rural-Urban interdependencies and climate change (CC). This helped raise awareness amongst local government and other stakeholders regarding urban-rural linkages, urban food systems and their vulnerability to climate change, highlighting important knowledge gaps surrounding urban food security. An experiential learning approach supported peri-urban horticultural producers to work together with other key agricultural stakeholders (e.g. researchers, extension, micro-credit, stockists, and NGOs) and develop horticultural learning plots on which they experimented with soil water conservation techniques (including admixture of manure, reduced width and levelling of seed beds), new varieties, tower gardening techniques (important for situations where land and water are scarce, and for women and disabled persons), different pesticide application methods and crop diversification opportunities (such as sunflower production fields). The process strengthened farmers’ ability to analyse and test ways of improving their situation, to link with other stakeholders and led to a fast uptake of sustainable technologies. The participating farmers managed to significantly increase their profits from horticultural production through increased yields and quality (and therefore prices) and reduced water and land requirements. Neighbouring farmers requested training from the learning group members and copied new practices. In Malawi, urban agriculture was incorporated into national and local government policy and will build on the project’s activities recognising that horticultural systems can be adapted to both improve capacity of vulnerable people and strengthen resilience of food systems.

NRI’s Dr Tanya Stathers and Richard Lamboll participated in the project design, urban food systems situation analysis, and the multi-stakeholder learning processes.

Assessing the poverty impact of social and environmental voluntary standard systems in the Kenyan tea sector

Dates: 2010-2013

Partners: Matrix Kenya

Donor: FCDO (previously DFID)

Background: Social and environmental voluntary standards, such as Fairtrade and Rainforest Alliance certification, are becoming increasingly common in global value chains. However, there is limited systematic evidence available on the impact and development potential of such standards. Donors, the media, NGOs, academics and development practitioners, as well as the voluntary standard bodies themselves are all keen to understand better what difference these standards make to disadvantaged workers and smallholders.

Objective: to systematically examine the impact of voluntary social and environmental standards on poverty and livelihoods, particularly for the most disadvantaged workers and producers in developing countries.

Results: The impact of social and environmental voluntary standards systems was studied in tea (in Kenya and India) and cocoa (in Ghana and Ecuador) amongst smallholder, outgrowers and estate producers. The study used large scale quantitative surveys and numerous sequential qualitative interviews with various stakeholders (e.g. producer organisation managers, smallholder and outgrowers famers (men and women), estate workers (men and women), key informants (e.g. local leaders, academics, trade unions), standard bodies).

Amongst smallholder growers tea farming is their main source of income. The strict quality criteria, increased plucking frequency and crop husbandry trainings associated with the Fairtrade and Rainforest Alliance certifications have led to improved green leaf quality and higher yields which translates to higher tea incomes particularly when the tea prices are high. They have been able to invest more in their children’s education, and the Fairtrade premium has been used for a wide range of community investments. These farmers incur long-term and short-term costs associated with being certified but generally feel the benefits outweigh the costs. The detailed findings of certification impacts for smallholders, outgrowers and estate workers are presented in the final report (Stathers, Gathuthi et al., 2013. Poverty impact of social and environmental voluntary systems in Kenyan tea).

NRI’s Dr Stathers led the Kenyan study involving design and implementation of the field work, and analysis and reporting of all the information collected.

  • Shaw MlamboGrain postharvest pest management in maize smallholder systems in a changing climate – University of Zimbabwe
  • Macdonald MubayiwaSmallholder postharvest technologies to manage climate-related risks in selected sorghum production systems - University of Zimbabwe
  • Charles SinganoInvestigation of grain postharvest technologies and systems for managing climate-related risks in smallholder farms of Shire Valley, southern Malawi – University of Zimbabwe
  • Tinashe NyabakoDevelopment of a smart-phone based decision-support system for grain postharvest management in Zimbabwe – University of Zimbabwe
  • Onika StellingburgAn investigation into the factors that influence food choice among Gillingham North Residents – University of Greenwich
  • Committee member of the International Working Conference on Store Product Protection
  • Reviewer for various research journals including Food Policy, Food Security, Stored Products Research, Crop Protection, Agricultural Education and Extension amongst others
  • Proposal reviewer for various donors and organisations
  • Award: De Montfort prize as one of Britain’s Top Younger Researchers at the House of Commons in March 2001
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