Sustainable agricultural soil management by recycling algal biomass to land

Grantham Scholar Dr Emanga Alobwede is now the head of Environmental Science at BX, a climate tech start-up. At the Grantham Centre she researched the recovery of algal biomass and the restoration of soil.

On being a Grantham Scholar

“Being a Grantham Scholar was a unique (PhD) experience.

Not only was it unique in its interdisciplinary nature, but there was the additional element of fostering our communication and public engagement skills. This is an important skill that scientists need to possess as we carry out cutting edge research but at times fail to take that out of the laboratory and communicate this effectively to policymakers, practitioners, etc.

As a Grantham Scholar, I learned how to conduct robust scientific research. And now I am in a position where I communicate scientific research and findings to the appropriate audiences for the purpose of ultimately applying it to decision making.”

Emanga’s project at the Grantham Centre

Intensive agriculture depletes soil organic matter, resulting in loss of soil macro-aggregates and their positive effects on soil water and nutrient holding capacity. Soil degradation now limits the productivity of elite modern high-yielding varieties of crops like wheat. Furthermore, loss of soil structure increases risk of flooding and run-off pollution. Run-off pollution leads to nutrient enrichment of aquatic systems and algal blooms. Algal blooms cost the UK an estimated £75-114 million per year. The increased application of fertiliser further exacerbates the problem of eutrophication and a major concern for future food security is that phosphorus originates from limited rock reserves.

Recovery of algae from polluted lakes and ponds has the potential to break the eutrophication cycle and the technology to do this efficiently is only now being developed. Once recovered, the algal biomass has a variety of uses including addition to soils. Benefits include increasing soil nutrient content, structure, aggregate stability and fertility, whilst reducing nutrient-run-off to watercourses compared to direct additions of manures or inorganic fertilizer. To date there have been no systematic studies of the properties of algae that optimise these benefits. This project aims to link the recovery of algal biomass from eutrophic water to the restoration of soil organic matter, rebuilding soil aggregates and sustainably recycling nutrients.


Emanga on the BBC's Horizon: Feast to Save the Planet
Dr Emanga on the BBC’s Horizon: Feast to Save the Planet

In 2021, Emanga appeared on the BBC Horizon: Feast to Save the Planet. The episode focused on the environmental impact of food. Emanga was on the show to explain how her research into algae has implications for our diet. For example, algae could help reduce our reliance on synthetic fertilisers and improve degraded soils. You can watch the episode on IPlayer.

The advantages of algae as biofertilisers in agriculture by Emanga Alobwede. In this blog, Emanga introduces the benefits to sustainability of using algae as biofertilisers in agriculture.

Synthetic ecology for algal cultivation by Emanga Alobwede. Emanga discusses synthetic ecology, which may be a more sustainable way to grow algae for biofuels.

Soil Association comes to Grantham Centre: the fight to save soil. In 2015, Emanga Alobwede and Angesh Anupam organised an event about soil at the Grantham Centre. Building UK’s Soils featured experts from the Soil Association.

Review: A Safe Operating Space For Humanity by Emanga Alobwede. Emanga and the Grantham Scholars review the controversial but widely cited paper A Safe Operating Space For Humanity.

Social media

You can find Dr Emanga Alobwede on Twitter @EmangaAlobwede

Research groups

Emanga is part of the Algal Biotechnology Sheffield Network.

Emanga Alobwede’s publications

The Fate and Distribution of Microalgal Nitrogen When Applied as an Agricultural Soil Fertiliser and Its Effect on Soil Microbial Communities. Emanga Alobwede, Anne Cotton, Jonathan R. Leake and Jagroop Pandhal. Phycology 2022, 2(3), 297-318;

Circular economy fertilization: Testing micro and macro algal species as soil improvers and nutrient sources for crop production in greenhouse and field conditions



Dr Jagroop Pandhal

Department of Chemical and Biological Engineering