UK ECN site (T06 ROT) is funded through the Rothamsted Long-Term Experiments National Capability (LTE-NCG). Rothamsted is located about 35 km North of London, UK (51° 48’ 34.44” N, 0° 21’ 22.76” W) in the county of Hertfordshire. It covers about 330 ha, all of which is included within the Rothamsted ECN site. The estate contains several ecosystems, including managed arable and grassland fields, naturally regenerated and ancient woodland, the river Ver and more recently energy crops e.g. short rotation coppice willow and miscanthus grass. It is a rural area within an urban landscape, surrounded by the town of Harpenden to three sides and the village of Redbourn on the south-west side. The larger conurbations of Luton, St. Albans and Hemel Hempstead, together with the M1 motorway and London Luton Airport, are within an eight mile radius. The Park Grass Hay Experiment (est. 1856) is the principal target sample site (TSS) for the majority of the ECN protocols at Rothamsted. This experiment is widely acknowledged to be the oldest continuing agro-ecological experiment in the world; it is recognised internationally as an important site for long-term studies on biodiversity and ecology. The experimental plot on Park Grass of most interest to the ECN, in relation to physical and atmospheric inputs is Plot 3, Section d (Plot 3d). This plot receives no inorganic or organic inputs apart from atmospheric deposition.