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.
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