Nitrous Oxide and Ammonia Emissions from Multiple Pollutant Cracking Clay Experimental Sites. Devon, 2010-11

An experiment was conducted at North Wyke, Devon, UK, using 1 ha hydrologically isolated grassland plots on a clay loam soil (38% clay) overlaying an impermeable clay subsoil (the Rowden facility). Half of the plots are drained, with tile drains at 40 m spacing and 85 cm depth, with permeable backfill to within 30 cm of the surface, and with secondary mole drainage at 40 cm depth and 2 m spacing. Cattle slurry was applied at a target rate of 50 m3 ha-1 using a trailing shoe slurry spreader to each of three replicate drained and undrained plots at three times of year: autumn (October 2010), spring (early February 2011) and summer (late June 2011). There were, however, only two replicate plots for the spring cattle slurry undrained treatment. At each application timing three replicate control plots, receiving no slurry, were also established on both the drained and undrained treatments. Nitrous oxide emissions were measured from each plot following slurry application, using the static chamber method, with 5 replicate chambers located in a sub-plot (18 x 6 m) at the centre of each 1 ha plot. Emission measurements were made on up to 40 occasions over a 12 month period following each slurry application. An annual emission factor was derived for each slurry application timing and drainage treatment as the net (of control value) annual cumulative N2O-N flux expressed as a percentage of the slurry N applied. Ammonia emissions from slurry-treated plots were measured for 7 days following slurry application, using the micrometeorological mass balance technique, employing passive flux samplers deployed on masts located at the centre and upwind edge of each plot. The Devon, 2010-11 experiment contains data sets of; annual nitrous oxide emissions, annual nitrous oxide emission factors, total ammonia loss, temperature, rainfall and associated soil and manure measurements