The results of the study, published in Water Science and Technology show that sub-surface leaching of phosphates from fertiliser applied to grassland presents a sustained threat to surface and groundwater quality throughout the year.
Measurements were taken from soil beneath cut grassland at depths of up to 1.35m. When 25kg/yr/ha of ‘triple super phosphate’ fertiliser had been applied to the soil (in line with UK government guidelines), average total phosphate levels of up to 152µg/l were recorded in the soil leachate.
The results are among the first to show clearly that the sub-surface leaching of phosphates is a serious threat to water resource quality, even when fertiliser is applied at approved levels for agriculture.
- UK nitrate-vulnerable zones (NVZs) are to be extended, according to Department of Environment, Transport and the Regions secretary of state Chris Mullin. The extension is to be proposed in a new consultation paper to be released later this year, which will contain a number of proposals aimed at improving the UK’s compliance with the EU Nitrates Directive. For example, nitrates will be monitored in all freshwaters and not just drinking waters. NVZs were introduced in the UK in 1996, to help regulate agricultural fertiliser use in areas where nitrate levels in drinking water had exceeded 50µg/l. There are currently 66 NVZs in the UK, mainly in heavily cultivated areas of the south east.