Farming in Africa using less water
Aims
Working with West African farmers to develop water-saving irrigation techniques.
Overview
Project Lead, Professor Ian Dodd explains:
Globally, fresh water is a scarce resource, and agriculture is the main user. Many farmers have limited access to water, but they need it to grow crops. Plants are more than 90% water (by weight), and they transpire many times their own weight of water each day. Plants lose water through their stomatal pores (place your hands together in prayer and keeping your fingertips and wrists together, move your fingers apart and back together to simulate stomatal movement) on the underside of the leaf. The stomata must open to allow the plant to photosynthesise (to gain carbon to allocate to seeds and fruit) but this allows transpiration (water loss from the leaf). Partial stomatal closure in response to mild soil drying can decrease transpiration while maintaining photosynthesis. Because farmers are worried that lack of water will decrease their crop yields (and income), often they over-irrigate their crops. By working with West African researchers and their farming communities, we are introducing water-saving irrigation techniques that save water and maintain yield, based on our understanding of factors regulating stomatal movement. We are working on important local crops (rice, tomato and maize) that are highly water-consuming.
Results and Outcomes
Tab Content: For Partners and Engagement
We’ve introduced our partners Council for Scientific and Industrial Research (CSIR) to new irrigation techniques and scientific instruments to monitor plant performance. We’ve run staff training workshops on the roof-top at Lancaster University Ghana in Accra (with potted plants supplied from a local nursery) and in the field at the Crops Research Institute (CRI), Kumasi. Instruments vary from quite basic (perforated plastic tubes sunk into the soil profile to measure the height of the water table in rice crops) to more sophisticated (thermal cameras integrated in smartphones to determine transpirational cooling of plant leaves). Our partner’s appetite for learning has been really encouraging, with CRI staff also running training workshops for CSIR staff from other institutes as our research occurs at different sites in Ghana. Moreover, our partners have visited Lancaster to undertake greenhouse-based experiments to reinforce their practical skills and to ensure an integrative research programme addressing fundamental plant physiological mechanisms and delivering practical solutions for farmers.
Alternate wetting and drying (AWD) of rice can decrease crop irrigation water requirements by 30%, while maintaining grain yields. This is especially important in Ghana as domestic production cannot sustain the demand for rice, and the government’s “one village, one dam” policy means that communities need to manage their water resources wisely to maximise outputs. Another irrigation technique (partial rootzone drying, PRD), suitable for row crops, waters only every second furrow at each irrigation event. Again, significant water savings can be made without compromising crop yields. These results suggest that current practices are inefficient, and may cause additional problems such as greater production of greenhouse gases in rice, and leaching of nutrients in other crops.
While farmers may be less concerned with these issues, crop quality is paramount. At open days that CRI has run in Kumasi, local farmers have preferred the appearance of AWD rice crops, auguring well for community adoption. Dr Stephen Yeboah of CRI said “Working with Lancaster has opened our eyes to these techniques and enhanced our community engagement activities.”
Tab Content: For Academics
From past projects we were already aware of the potential of these specific irrigation techniques to save water and sustain yields, based on our understanding of plant biology. However, previous studies showed considerable variability in crop yield responses to partial rootzone drying (Dodd 2009) and farmers’ willingness to adopt these techniques (Howell et al. 2015). Since we could not find any evidence that farmers had already adopted these techniques in west Africa, we were uncertain whether they would be suitable, from either agronomic or social perspectives.
Having expert local knowledge of Ghanaian farming systems was critical to our chances of evaluating these techniques and eliciting community interest. Fortunately, our collaborators developed irrigation infrastructure at their research institute to conduct trials, and engaged locally to spread the word to farmers. Considerable time “in-country” (pre-covid19) was critical to us establishing new professional working relationships, and clarifying uncertainties on the theory and practice of the irrigation techniques. Basing a Lancaster staff member in Kumasi during part of the irrigation season was vital to help in troubleshooting any issues that our partners had in using the portable scientific instruments used to collect data on crop response. Probably this boosted partner confidence in developing working relationships that were more resilient to some of the more administrative elements (e.g. quality control checks on data entry and analysis) integral to any project.
Apart from the obvious adaptation process to online ways of working necessitated by covid19, one of the challenges has been maintaining Lancaster staffing on this project. Sustainable development projects place greater expectations on postdoctoral staff (e.g. knowledge exchange, technology transfer, additional mentoring) than traditional laboratory-based plant sciences research projects. Often there is considerable pressure to generate (and publish) significant fundamental research findings to ensure career development, while ensuring that laboratory work is sufficiently relevant to tell a coherent research narrative to funders. With 3 Lancaster staff working sequentially on the same project, maintaining continuity of research expertise and partner engagement has been paramount.
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