The ‘Cities’ episode, aired on 30 July, features John as part of its report on how agricultural ammonia emissions from slurry contribute towards air pollution. John’s expertise is called upon to explain how improved slurry application techniques could reduce these emissions.
Rather than broadcast spreading slurry on the soil, Countryfile visited a farm in Cambridgeshire that uses shallow injection equipment to apply slurry.
“Slurry is spread with precision application equipment, which supplies plant nutrients to the soil,” John told Countryfile’s Tom Heap. “By injecting it into the ground and putting it right on the soil surface, we’re able to get the slurry exactly where the crops need the nutrients. We’re minimising the ammonia-emitting surface area of the slurry, so we’re reducing the ammonia emissions, typically by up to 50%, compared with conventional surface broadcast.”
John (right) explains the technique to Countryfile’s Tom Heap
Countries that have more intensive livestock farming like Holland and Denmark are already using these techniques as standard. ADAS research has demonstrated the effectiveness of this equipment in reducing ammonia emissions and increasing the fertiliser value of the slurry. “We’re seeing more farmers and contractors showing interest in this sort of equipment and we’re optimistic it will become more widely used in the future,” said John.
As well as reducing emissions and waste through the method of application, farmers can increase efficiency through proper slurry storage and the timing of application. “It’s important to have sufficient storage capacity for slurry so that we’re not spreading it at the wrong time of the year,” John continues. “It’s important to spread the slurries in the spring to minimise the risk of nitrate leaking. There is also the potential to cover slurry stores to reduce ammonia emissions.”