public read uid=datalibrarian,o=unaffiliated,dc=ecoinformatics,dc=org all Professor Deli Chen The University of Melbourne Reader

Department of Resource Management and Geography, Melbourne School of Land and Environment The University of Melbourne Parkville VIC 3010 Australia

+61 3 8344 8148 delichen@unimelb.edu.au http://www.findanexpert.unimelb.edu.au/researcher/person13219.html Dr. Helen Suter The University of Melbourne Research Fellow

Department of Resource Management and Geography, Melbourne School of Land and Environment The University of Melbourne Parkville VIC 3010 Australia

+61 3 8344 0179 +61 3 8344 5579 helencs@unimelb.edu.au http://www.findanexpert.unimelb.edu.au/researcher/person16560.html Ms. Siobhann McCafferty Institute for Future Environments, Queensland University of Technology Data Librarian

2 George Street Brisbane QLD 4001 Australia

+61 7 3138 0457 siobhann.mccafferty@qut.edu.au Custodian/Steward This data package describes a field trial conducted to assess the influence of urea applied with and without a urease inhibitors NBPT, and as a fine particle (FPA) or liquid application (UAN) on loss of the indirect greenhouse gas ammonia (NH3) from a ryegrass pasture (Lolium perenne L) in autumn and spring of 2010. The trial was designed to assess both fertlizer type and seasonal impacts on NH3 loss. Ammonia loss was measured on 50 m diameter circles using a passive ammonia sampling system of Leunig et al (1985) where NH3 was trapped in centrally located acid traps. Data was collected on NH3 captured, soil mineral and urea N, plant biomass production and nitrogen content as well as local climatic conditions. NH3 Ammonia emissions N-(n-butyl) thiophosphorictriamide nBTP Urease inhibitor Agrotain Green urea Ammonia volatilisation Pasture Urea hydrolysis Murroon VIC 0502 0799 anzsrc-for 2010-04-12 2010-12-23 Murroon, Victoria, Australia 143.81 143.81 -38.43 -38.43 1287716061357 1287715838119

Ammonia volatilization was studied in three treated circular plots of 25 m radius. The centres of the areas were 200 m apart and the areas were located so that a line joining the centres was perpendicular to the prevailing wind direction to ensure that NH3 emissions from one area did not interfere with emissions from the others. Ammonia loss was determined with a simplified mass balance micrometeorological method using the Leuning et al. (1985) NH3 samplers. Duplicate samplers were used to measure horizontal flux density at 0.8m above the crop at the centre of the circular areas and vertical flux was determined following Denmead (1983) and Turner et al (2010). Background measurements were made with samplers placed on masts located on the upwind side of the treated areas. Ammonia emission was measured twice daily from April to May 2010, and September to October 2010. Ammonia captured in the Leuning samplers was analysed using a SAN++ segmented flow analyser (Skalar Analytical).

Leuning samplers. Skalra SAN++ autoanalyser.

Soil samples were collected from within the circles and the background area for Urea, NO3- and NH4+ analysis using composites of 60 cores. Soil samples were immediately oven dried (40oC) in autumn, passed through a 2mm sieve and extracted in the laboratory as soon as possible. In spring, samples were extracted on site, to minimise the risk of urea loss in drying prior to extraction. Each composite sample was mixed and two subsamples taken (~20 g soil, air dry basis in autumn; 25 g field moist soil in spring) for analysis. Soils extractions (1:5 soil: solution ratio) were carried out in 250 mLplastic bottle, shaken for 2 hour with 100 mL of 2 M KCl containing 5 mg/L phenylmercuric acetate solution and samples were filtered through Whatman No 42 filter papers. The filtrate was collected and kept in a freezer (-20oC) and then defrosted and analysed for urea, NH4+, and NO3- using a Skalar SAN++ segmented flow analyser

Skalar SAN++ segmented flow analyser.

Pasture biomass was collected from beneath a 2 x 1 m pasture cage one month after fertilization. Pasture samples were analysed at a commercial laboratory for biomass weight and Kjeldahl nitrogen.

The trial was conducted on a two year old perennial ryegrass pasture (Lolium perenne) with two 3 week sampling campaigns, one commencing in April 2010 and the other commencing in September 2010. A single circle of 25 m diameter was used for each treatment and duplicate samplers were used to collect the NH3. Duplicate ammonia traps for each treatment were changed twice daily at commencement of the trial and then less frequently to 21 days. Soil sampling as done every few days. Biomass samples were collected after 1 month 1287716061357 Principal Investigator 1287715838119 Principal Investigator DAFF/GRDC