Developing a resilient and regenerative tea production system

Tea can be regarded as the UK's national drink - we consume around 36 billion cups a year, and the tea processing industry and supply chain employs more than 3000 people in the UK. Export of tea products from the UK is also a significant business. Ekaterra, the world's largest tea provider has tea plantations in Kenya, Tanzania and Rwanda with tea production and breeding operations. However, these plantations are under pressure from climate change, due to prolonged and more frequent droughts. Tea production also relies on synthetic nitrogen fertilizers that have a large carbon footprint, contributing to greenhouse gas emissions. Ekaterra has formed a strategic vision to make its tea plantations "climate positive" so they will contribute to carbon sequestration and increased biodiversity, i.e. they will contribute to "regenerative agriculture". The major challenges to this vision are to reduce synthetic nitrogen use, and to keep the crop productive and resilient in times of drought. In this Prosperity Partnership project, Ekaterra and Cranfield will work together to address these challenges.
We will develop methods to collect and analyse canopy image data from tea plantations and breeding sites using drones and cameras able to estimate the leaf temperature and chemical composition. The data will be collected and fused with other data though a digital platform for tea crop management - "Internet of TeaTM" or "IoTeaTM" - jointly developed by Ekaterra and Cranfield. We will use the data to develop more accurate predictive models that can help farmers to make better crop management decisions in terms of when and how much nitrogen to apply and in what form, when to harvest and the environmental impacts of management decisions. We will develop and test alternative organic sources of nitrogen and make sure that our models work with these more slowly mobilizable products. The same drone image techniques, and other methods to characterize root development, will also be applied to Ekaterra's breeding programme to directly select new tea clones that are more efficient at recovering nitrogen from the soil, or accessing water deep in the soil profile during droughts. Where we find clones with contrasting behaviour we will carry out studies to understand why they are different. This work will be extended, using modern genomics technologies to understand which parts of specific chromosomes or individual genes affect these processes - Ekaterra can then use this information to more rapidly select novel and more sustainable tea clones in the future.
Overall, the aim of the Prosperity Partnership is to make major advances towards regenerative tea production by developing solutions to reduce nitrogen fertilizer-related greenhouse gas emissions while also increasing the resilience of tea soil-crop systems to drought. The results will be used to support Ekaterra's own tea business, e.g. through more resilient and sustainable production, and new varieties and technologies could be licensed to other tea producers. New digital agriculture approaches developed in the project could be licensed to other sectors, including other plantation crops. During the Partnership, there will be reciprocal knowledge transfer and formal training to upskill the Ekaterra team in a range of techniques used in the project.

Tea is a perennial, outbreeding and vegetatively propagated crop grown as non-grafted clones or as grafted scion-rootstock "composite" bushes that often remaining in production for >40 years. It is produced in cool climates, is sensitive to drought and uses a significant amount of mineral fertiliser, such that 73% of the greenhouse gas (GHG) emissions for tea production are from mineral fertilizer manufacture and associated emission of nitrous oxide from the soil. Ekaterra Ltd is the largest tea producer in the world with 8,700 hectares of tea production in Kenya where climate change (reduced rainfall in the dry season and higher temperatures) is predicted to reduce the area of tea production by up to 42% by 2050; deeper and more prolonged dry seasons are already reducing yields. Our project aims to address the challenges of (i) reducing GHG emissions associated with tea production to help with the global call to reach net zero emissions and (ii) developing tea varieties and production systems that are less sensitive to drought.
We will build on an existing digital platform "Internet of Tea" co-developed by Ekaterra Ltd and Cranfield University that incorporates a model for tea growth-and-development known as CUPPA-Tea. We will develop protocols for capturing and analysing imagery of crop canopies using drones at an Estate scale along with digital soil maps and then use this information to improve the modelling of tea growth in response to drought and nitrogen, especially for understanding the potential benefits of novel organomineral fertilisers and the impacts on GHG emissions. We will test hypotheses arising from CUPPA-Tea that relate emissions to rooting depth and morphology, soil pH, C:N ratios and microbial activity. We will use the same drone data platform to develop phenotypic and genomic selection protocols for drought resistant varieties, and to search for genetic markers for root traits that may contribute to drought resistance and nitrogen capture.