Biochar is being trialled in poultry housing and manure as a method of reducing air and water pollution from farms in the UK.
The UK Centre for Ecology & Hydrology (UKCEH) is part of the new Defra-funded, two-and-a-half year project, led by Black Bull Biochar (BBB), to address two of the biggest challenges in poultry and wider agriculture – ammonia emissions in the birds’ housing and phosphorus pollution from manure when applied to arable land.
Biochar is produced when biomass – typically wood – is heated to high temperatures without oxygen. The process is known as pyrolysis, and when completed effectively, produces a biochar that is effective at absorbing nutrients.
BBB is developing the biochars while UKCEH, Scotland’s Rural College (SRUC) and farms with both poultry and arable operations will carry out testing in labs, research facilities and on farms, respectively. The farms will be based in the River Wye catchment area, where most land use is agricultural and around 25% of UK poultry production is concentrated.
The River Wye is experiencing declines in biodiversity as. surplus nutrients in the water – known as eutrophication – cause the proliferation of algae that is outcompeting plants, preventing fish egg laying and lowering oxygen concentrations, resulting in toxic conditions. Poultry manure applied to arable land is one of the major sources of phosphorus pollution in the Wye.
Solutions are required
Dr Dafydd Elias, a soil biogeochemist at UKCEH, explains: “Poultry manure is a rich source of phosphate and large amounts are spread across surrounding agricultural land as an organic fertiliser. However, this poses an environmental risk when phosphates are washed into the river by rainwater and contributes to the eutrophication of waterways.”
He added: “Cost-effective solutions that mitigate phosphate runoff into the River Wye are urgently required to restore water quality and protect biodiversity.”
In lab environments, biochar has been shown to reduce ammonia emissions from droppings by up to 58%. The project partners aim to develop a cost-effective biochar for UK growers which will be added to birds’ bedding and bind ammonium to its surface, preventing release into the atmosphere as ammonia gas.
Meanwhile, modified biochars are proven to be highly efficient at adsorbing phosphorus under lab conditions but these are not commercially accessible. The project team will seek to prove a cost-effective biochar for farmers that will support the safe use of poultry manure, an important and renewable fertiliser. The biochar will work by binding highly mobile phosphates in the manure to its surface, preventing leaching and run-off into watercourses, and enhancing plant nutrient accessibility.
Defra is funding the project through The Farming Innovation Programme’s Nutrient Management competition, delivered by Innovate UK.
