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Date: Tuesday 14th September 2010
Time: 12:30-13:30pm
Venue: Murrumbidgee Irrigation\CSIRO Seminar Room, Research Station Road, Griffith, NSW.
Greenhouse gas emissions from sugarcane agriculture
Dr Ben Macdonald, CSIRO Land and Water
Abstract
The main gases of concern are the direct greenhouse gas nitrous oxide (N2O) and the indirect greenhouse gases nitric oxide (NO) and nitrogen dioxide (NO2), the last two being known collectively as NOx, and ammonia (NH3). Nitrous oxide is a powerful greenhouse gas with a global warming potential 298 times that of CO2. In the atmosphere, the indirect greenhouse gases take part in chemical reactions and eventually, they and their products are deposited on earth where they can undergo nitrification and denitrification with the consequent formation of N2O. Previous work with sugarcane showed that emissions of NH3-N to the atmosphere from surface applications of urea could be as much as 40% of the N applied. New practices that bury the fertilizer can reduce NH3 losses although whole of season reductions have not been quantified previously; nor have those of NOx.. This presentation will report emissions of N2O, NOx and NH3 from a rain-fed, fertilised, trash-blanketed sugarcane soil at Mackay, Queensland measured using near-continuous automatic chamber and micrometeorological techniques for the whole of the 2006-2007 season and for the first 2 months of the 2007-2008 season. The nitrogen fertiliser was mostly urea applied at a rate of 150 kg N/ha into slits 10 to 15 cm deep. Nitrous oxide emissions accounted for around 5 kgN/ha, or 3% of the applied N in the 2006-2007 season, with NOx and NH3 together accounting for around 1.5 kgN/ha, or about 1% of applied N. Allowing for an estimated loss of 1.5 kg N2-N/ha through denitrification, the net loss would amount to 8 kg N/ha or 5% of the N applied. Carbon and nitrogen emissions from the present and earlier studies will also be discussed.
The main drivers of N2O and NOx emissions appeared to be the availability of a mineral N source and the water content of the near-surface soil. However, NH3 emissions appeared to have a source different from the soil, possibly the trash and the sugarcane foliage. Our emission measurements indicate that only insignificant amounts of N2O are likely to be formed through the deposition pathway in the main sugarcane growing regions and that burying urea fertilizer is very effective in preventing N losses through NH3 volatilisation. Only 0.3% of the fertilizer applied was lost as NH3 over the 2006-2007 growing season.
About the speaker
Dr Ben Macdonald has recently joined CSIRO Land Water from the Australian National University in December 2009. He is currently working within the soil plant and atmosphere interaction group with a focus on the measurement of gaseous exchange from agricultural and natural ecosystems using chamber and micrometeorological techniques. His research work has taken him from investigating chenopod shrub-lands, coastal acid sulphate soils to surface and ground water interactions.
Date: Friday 10th September 2010
Time: 12:30-13:30pm
Venue: Murrumbidgee Irrigation\CSIRO Seminar Room, Research Station Road, Griffith, NSW.
Adapting to Drought in the San Joaquin Valley of California
Dr Jim Ayars, U.S. Department of Agriculture – Agricultural Research Service
Abstract
This is an overview of the strategies being taken by farmers in the San Joaquin Valley of California to cope with the current limited water supplies. It gives a brief case study of the response of one irrigation district.
About the speaker
Dr. Jim Ayars is a research agricultural engineer with the U.S. Department of Agriculture – Agricultural Research Service in Parlier, CA. He has 30 years of experience in research related to the integrated management of irrigation and drainage systems in arid irrigated agriculture. He has investigated the management of irrigation systems in the presence of shallow saline ground water and in-situ use of ground water by crops. He is currently studying the water requirements of horticultural crops grown in the saline soils of the San Joaquin Valley.
Date: Thursday 17 June 2010
Time: 2pm – 4pm
Venue: Murrumbidgee Irrigation\CSIRO Seminar Room, Research Station Road, Griffith, NSW.
Estimating crop water consumptive use using the METRIC satellite-based surface energy balance method
Dr Jeppe Kjaersgaard,
Res. Assoc. Prof., Water Resources Research Program, University of Idaho, Kimberly Research and Extension Centre
Abstract
It is important to quantify the consumptive water use by the vegetation when managing local and regional water resources in irrigated areas. Suitable models and algorithms applied to high resolution (30 m) satellite imagery provide a cost effective and time efficient method to obtain evapotranspiration estimations from bare soil and vegetation. The METRIC image processing model calculates net radiation, soil heat flux and sensible heat flux through a number of steps before estimating evapotranspiration as the residual from the energy balance. Sensible heat flux algorithms are calibrated using an operator selected wet and dry pixel. The complete energy balance obtained from the satellite images is calibrated using ground based reference evapotranspiration estimations.
The presentation will give an overview of the theory behind METRIC, give examples of some of the applications where the METRIC procedure have been used to estimate crop consumptive water use agricultural crops and in orchards, and show how the METRIC output have been used in the state of Idaho and elsewhere.
About the speaker
Dr Jeppe Kjaersgaard is part of the water resources research program at the University of Idaho Kimberly Research and Extension Center. His research interests include measurements of states and fluxes in the atmospheric boundary layer and the interaction of soil, plant and atmosphere in agricultural and horticultural production systems. Over the last three years he has been focusing his research on further development and applications of the satellite-based surface energy balance estimation model METRIC, including estimating energy fluxes from complex vegetation systems including riparian woody vegetation, orchards, vineyards and forests.
Jeppe Kjaersgaard received a Masters degree in agronomy from the Royal Veterinary and Agricultural University, Copenhagen in 2003 and a PhD in biometeorology from the University of Copenhagen in 2007. He is currently an assistant research professor at the University of Idaho.
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