Farmyards are a potential source of phosphorus which, if not managed correctly, can be lost to watercourses and contribute to eutrophication. In a new scientific paper from the Agri-Food and Biosciences Institute (AFBI) the runoff, management, and infrastructure factors that control phosphorus risk were ranked by 147 experts from the water quality, farm advisory, policy, and research sectors.
The results of the survey found that silage effluent was prioritised as the greatest risk factor. Effluent is produced in the first 2 weeks after ensiling; however, if rainwater enters the pit or silage bales it can be released at other times.
All silage effluent must be safely collected in storage tanks and wilting can minimise its production. Runoff from the farmyard to watercourses or to farm drains was also considered to be a major risk factor. Preventing these discharges by ‘breaking the pathway” e.g. by diverting water runoff to storage tanks, reduces the risk to watercourses. The frequency of yard cleaning was also highly ranked and is a cheap and effective way to reduce the phosphorus content in farmyard runoff during rainfall events.
The finding of this survey has contributed to the development of a Farmyard Risk Assessment tool and will be implemented by on a voluntary basis in the coming months. In addition the AFBI team is monitoring runoff from farmyards to measure the amounts of phosphorus lost during rainfall events.