Agricultural Greenhouse Gas Inventory Research Platform - InveN2Ory. Dung and urine experimental site in Devon, 2012

N - Datasets

Cardenas, L. M., Misselbrook, T. H. and Donovan, N. 2017. Agricultural Greenhouse Gas Inventory Research Platform - InveN2Ory. Dung and urine experimental site in Devon, 2012. Freshwater Biological Assoc. https://doi.org/10.17865/ghgno562

AuthorsCardenas, L. M., Misselbrook, T. H. and Donovan, N.
Abstract

An experiment was carried out at Rothamsted Research - North Wyke near Okehampton, south-west England (clay topsoil texture) using small field plots (3 x 6 m) arranged in a randomised block design with three replicates per treatment. Cattle urine (at 5 L/m2), synthetic urine (at 5 L/m2) and cattle dung (at 20 kg/m2) was applied to grassland in mid-May (spring), early-July (summer) and in late-September (autumn) 2012. The synthetic urine was prepared using the formulation described for “R2” in the paper by Kool et al., (2006). A control treatment was included where no urine or dung was applied. In a separate treatment, a commercially available nitrification inhibitor was tested; dicyandiamide (DCD) was pre-mixed with the urine prior to application to give an application rate of 10 kg /ha for the DCD. The urine and dung was collected from lactating dairy cows at Reading University, kept refrigerated at <4°C and applied in less than 2 days after collection. Following urine application to five 0.36 m2 areas of the plot (‘urine patches’), measurements of direct N2O-N were made over c.12 months, using 5 static chambers (1 per 0.36 m2 area, giving a total chamber surface area of 0.8 m2) and analysed by gas chromatography. Dung was applied using a trowel in five patches (60 cm x 60 cm) so that each patch was completely enclosed by a nitrous oxide static chamber. For soil mineral N and grass N uptake measurements, two additional areas of 2 m x 2 m were treated on each plot; one with 20 litres of urine and one with 80 kg of dung. Grass yields and N offtakes were measured following grass cuts in mid-June and late-August 2012 from the spring dung and urine application, early-August 2012 and late-May 2013 from the summer dung and urine application, and late-May 2013 from the autumn dung and urine application. The Devon, 2012 dung and urine experiment contains data sets of; annual nitrous oxide emissions, annual nitrous oxide emission factors, soil moisture, top soil mineral nitrogen (selected dates), temperature, rainfall and associated crop (grass yield and nitrogen offtakes) and soil measurements. Reference: Kool, D.M., Hoffland, E., Abrahamse, P.A and van Groenigen, J.W. (2006). What artificial urine composition is adequate for simulating soil N2O fluxes and mineral N dynamics? Soil Biology and Biochemistry 38, 1757-1763.

Year of Publication2017
PublisherFreshwater Biological Assoc
Digital Object Identifier (DOI)https://doi.org/10.17865/ghgno562
Keywordsnitrous oxide
urine
farmyard manure
nitrification inhibitors
grassland soils
clay soils
Publication dates
Online05 Apr 2017
FunderDepartment of Environment, Food and Rural Affairs
Scottish Government
Welsh Government
Department of Agriculture, Environment and Rural Affairs (DAERA), Northern Ireland
Data files
File Access Level
Open
Data collection period15 May 2012 to end of 10 Sep 2013
Geographic location
Devon, South West England, UK
Geographic region bounding box
(50.68, -4.04) to (50.85, -3.75)
Geographic coverageDevon, 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 an expanded neoprene rubber strip (Portmere rubber, SO14 5QZ) to form an air-tight seal following chamber enclosure with a lid (Cardenas et al., 2010). Chambers were pushed into the soil up to a depth of 5 cm and remained in place throughout the experiment, except during urine/dung application and grass cutting 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) a headspace sample was taken using a 50-ml syringe. Using a double needle system the sample was 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 routinely from three chambers located on the urine only treatment. A minimum of five samples were taken from each chamber at 15 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 and not stored for more than 2 days (to minimise potential leakage) using gas chromatographs fitted with an electron-capture detector and an automated sample injection system. The gas chromatographs were calibrated on a daily basis using certified N2O standard gas mixtures. An exchange of samples of chamber air and standard gas mixtures between labs from the different research organisations involved in the InveN2Ory programme of experiments who operated the GCs were carried out, to avoid the possibility of any bias in the results towards high or low values. Following urine/dung application, N2O flux measurements were carried out for 5 days immediately following urine/dung application, daily for a further 5 days during the next week, twice weekly for the next two weeks, every other week over the next c.four months, decreasing in frequency to monthly until the end of the 12 month sampling period. Prior to the urine/dung application N2O measurements were taken to provide baseline information. This sampling schedule resulted in an annual total of 33, 32 and 30 sampling days for spring, summer and autumn application respectively, starting from the day of each of the urine/dung 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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