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Saint-Sauveur-en-Rue, France

Waterlogging and salinity problems in major rice growing areas demand policies aimed at better management of land and water resources. This process can be facilitated through regional scale spatially distributed hydrologic-economic models that capture and integrate point scale processes at paddock, farm and irrigation area levels. The study develops an integrated hydrologic-economic framework that integrates hydrologic and economic responses for social and common pool optimum management in the Coleambally Irrigation Area, Australia. The results of hydrological-economic model indicate that the economic units with heavier soils and shallow watertables with minimum groundwater out flows are the best economic locations for growing rice as the total crop water requirements are minimised. Social and common pool optimum scenarios indicates, after accounting for externalities and groundwater dynamics, the optimal net returns could be achieved in about 15 years. There was not much difference between social and common pool optimum, however, common pool optimum show decline in net revenue after 23 years because of shallow watertable rise within 2 m of the surface. The current rice growing policies are mainly based on the clay content of soils and rice water use limits. This work has highlighted the importance of incorporating groundwater dynamics in deciding environmental policies for growing rice. © 2009 Springer-Verlag.

Khan S.,Paris | Khan S.,CSIRO | Rana T.,CSIRO | Carroll J.,CSIRO | Gabriel H.,Charles Sturt University
Paddy and Water Environment | Year: 2010

This paper describes the impact of rice hydraulic loading (percentage area under rice crop) on groundwater levels and salinity in the Murrumbidgee irrigation area (MIA), Australia using a MODFLOW-based modelling approach. The model simulations show that the groundwater levels will be in equilibrium after a fall of approximately 1 m under most of the areas, however, the groundwater salinity levels will rise by more than 1,000 μs/cm in most parts of irrigation area. If the rice growing area is reduced by 50 and 75%, there can be a net decline in groundwater levels during the first 2 years and then a new quasi-equilibrium will be established. To downscale these results at the farm level, SWAGMAN Farm model in conjunction with groundwater outflow rates obtained from a three-dimensional MODFLOW model was applied for determining net recharge rates under rice for different areas within the MIA. The highest net recharge during 2005-2006 season was 0.84 ML/ha (84 mm) in parts of the irrigation system, whereas the average net recharge due to rice hydraulic loading for the whole MIA during 2005-2006 season was estimated as 0.34 ML/ha (34 mm). © 2009 Springer-Verlag.

Paris | Date: 2007-11-20


Minier T.,University of Pecs | Guiducci S.,University of Florence | Bellando-Randone S.,University of Florence | Bruni C.,University of Florence | And 60 more authors.
Annals of the Rheumatic Diseases | Year: 2013

Objectives: The EULAR (European League Against Rheumatism) Scleroderma Trials and Research Group (EUSTAR) has identified preliminary criteria for very early diagnosis of systemic sclerosis (SSc). Our aim was to assess the prevalence of each proposed diagnostic item in a large observational patient cohort with Raynaud's phenomenon (RP). Methods: Baseline data of 469 RP patients enrolled into the Very Early Diagnosis of Systemic Sclerosis (VEDOSS) cohort are presented. Results: 68% of all RP patients were antinuclear antibody (ANA) positive. ANA+ RP patients more frequently had previous or current puffy fingers (PuFi) (38.5% and 23.3%, p<0.01) and an SSc pattern on nailfold capillaroscopy (NC) (53.6% and 13.4%, p<0.001) than ANA- patients. Telangiectasia, current digital ulcers and digital pitting scars were also commoner in ANA+ RP patients. 38% of ANA+ patients presented with all three features, which should raise suspicion of very early SSc (ANA+RP+PuFi constitutes a 'red flag'). These patients more frequently exhibited an NC SSc pattern, sclerodactyly and telangiectases compared to ANA+ patients without PuFi. Almost 90% of patients with 'red flags' had anti-centromere or anti-topoisomerase I antibodies and/or an NC SSc pattern, and fulfilled the EUSTAR criteria for very early SSc. Previous or current PuFi were present in 23.3% of ANA- RP patients, eight of whom also had an NC SSc pattern. Conclusions: In addition to well-characterised predictive factors, PuFi is an important sign raising suspicion for underlying very early SSc in patients with RP. The relevance of PuFi in ANA- RP patients should be clarified. © 2013 BMJ Publishing Group Ltd & European League Against Rheumatism.

Paris | Date: 2002-11-21

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