N - Datasets
Misselbrook, T. H., Donovan, N., Camp, V., Hodgson, C. J. and Chadwick, D. R. 2017. Nitrous Oxide and Ammonia Emissions from Multiple Pollutant Cracking Clay Experimental Sites. Devon, 2010-11. Freshwater Biological Assoc. https://doi.org/10.17865/ghgno768
|Authors||Misselbrook, T. H., Donovan, N., Camp, V., Hodgson, C. J. and Chadwick, D. R.|
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.
|Year of Publication||2017|
|Publisher||Freshwater Biological Assoc|
|Digital Object Identifier (DOI)||https://doi.org/10.17865/ghgno768|
|Online||11 Apr 2017|
|Funder||Department of Environment, Food and Rural Affairs|
File Access Level
|Data collection period||12 Oct 2010 to end of 16 Jun 2012|
Devon, South West England, UK
Geographic region bounding box
(50.68, -4.04) to (50.85, -3.75)
|Geographic coverage||Devon, South West England, UK|
|Data collection method|
Direct N2O emissions were measured with five static flux chambers (40 cm wide x 40 cm long x 25 cm high) per plot, covering a total surface area of 0.8 m2. The chambers were of white (i.e. reflective) PVC and un-vented with a weighted lid and neoprene seal allowing an air-tight seal to form following chamber enclosure. Chambers were pushed into the soil up to a depth of 5 cm and remained in place throughout the experiment, except during slurry application when chambers were removed, locations were marked, and chambers were re-instated to the same position as prior to removal. Chambers remained open except for a short time on each sampling day. On that day, ten samples of ambient air were taken to represent time zero (T0) N2O samples. From each chamber, after a 40-minute enclosure period (T40) one headspace sample was taken using a 50-ml syringe and flushed though a pre-evacuated 20-22 ml glass vial fitted with a chloro-butyl rubber septum and held at atmospheric pressure. The N2O flux was calculated using an assumed linear increase in N2O concentration from the ambient N2O concentration (T0) to the N2O concentration inside the chamber after 40-minutes enclosure (T40) (Chadwick et al., 2014). Throughout each experiment, the linearity of emissions through time was checked from three chambers located on the slurry plots; three times per week during intensive sampling periods and monthly at all other times. A minimum of four samples were taken from each chamber at 20 min intervals commencing at closure i.e. T0 and spanning the T40 sampling time. In order to minimise the effect of diurnal variation, gas sampling was carried out between 10:00 am and 14:00 pm and where possible between 10:00 am and 12:00 pm as suggested by IAEA (1992) and referred to in the IPCC good practice guidance (IPCC, 2000). Gas samples were analysed as soon as possible after collection (to minimise potential leakage) using gas chromatographs fitted with an electron-capture detector and an automated sample injection system. Following receipt in the laboratory, two replicates of one standard N2O gas were kept with the samples and were used to verify sample integrity during storage. The gas chromatographs were calibrated on a daily basis using certified N2O standard gas mixtures. Following slurry application, N2O flux measurements were carried out for 5 days immediately following slurry application, daily for a further 5 days during the next week, twice weekly for the next two weeks, weekly for the next week and every other week for four months, decreasing in frequency to monthly until the end of the 12 month sampling period. Prior to the first slurry application N2O measurements were taken to provide baseline information. This sampling schedule resulted in an annual total of c.40 sampling days starting from the day of slurry application. Measurements were taken over 12 months to follow IPCC good practice guidance and so that the results were directly comparable to the IPCC 2006 methodology default emission factor.
|Data preparation and processing activities|
Nitrous oxide fluxes from the five replicate chambers per plot were averaged. Cumulative fluxes were calculated using the trapezoidal rule to interpolate fluxes between sampling points.
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