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The wind drift and evaporation losses (WDEL) are high in arid, semi-arid and windward areas, and reduce the efficiency of the sprinkler irrigation system; therefore, this study was carried out in order to achieve a practical criterion and provide a relationship for accurate estimation of the wind drift and evaporation losses in different atmospheric conditions. The experiments were done at the Meteorological Station of the Faculty of Agriculture of Ferdowsi University of Mashhad using a line-source sprinkler irrigation system based on the single sprinkler installation method. To achieve the objectives of this plan, factorial experiment was performed on PGP sprinkler with regard to the two factors, the pressure of the sprinkler function (with three levels 1.6, 2.5 and 3.4 bar) and the diameter of the nozzle (with three levels of 4, 5 and 6 mm) with three replications (morning, noon and night). Assessing the result of the data variance analysis showed that the effects of pressure, aperture diameter, and time on the wind drift and evaporation losses are not significant. Investigating the main effects of these factors showed that the effect of aperture diameter on irrigation losses is significant at the level of the 1%. In order to further investigate, the comparison of mean losses data in three aperture diameter was done using Duncan′s test. The results indicated that aperture 4 with the losses of 44% had a significant difference with other diameters. This result suggests an increase in losses for smaller diameters due to the small droplets and the increase in wind drift. Also, the comparison of the mean losses data in three times showed that irrigation at noon with the losses of 44% had a significant difference compared to other times due to a significant increase in temperature and radiation of the sun and saturation vapor pressure deficit, and there is no significant difference between morning and evening irrigation. Also, analysis of variance showed that the effect of water pressure change between 1.6 and 4.3 bar does not have a significant effect on the WDEL in this sprinkler. In general, the results showed that increasing wind speed increases the losses of evaporation and wind. Also, this study suggested that changing the irrigation time in areas with hot and dry days, from day to night in summer, leads to a significant reduction of the wind drift and evaporation losses.

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Kholová, J., Hash, C. T., Lava Kumar P., Yadav, R. S., Kočová, M., Vadez, V. (2010) Terminal drought-tolerant pearl millet ( Pennisetum glaucum (L.) R. Br.) have high leaf ABA and limit transpiration at high vapour pressure deficit. J. Exp. Bot. 61

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oxygen isotope ratios in wood constituents of Pinus halepensis as indicators of precipitation, temperature and vapour pressure deficit . — Tellus B 57 ( 2 ): 164 – 173 . http://dx.doi.org/10.1111/j.1600-0889.2005.00137.x

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. , Leonardi , C. , Bertin , N. ( 2005 ) Analysis of growth and water relation of tomato fruits in relation to air vapor pressure deficit and plant fruit load . J. Plant Growth Regul. 24 , 1 – 13 . 17

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Acta Agronomica Hungarica
Authors: P. Almeida, L. Dinis, J. Coutinho, T. Pinto, R. Anjos, J. Ferreira-Cardoso, M. Pimentel-Pereira, F. Peixoto, and J. Gomes-Laranjo

. B. (1992): Control of photosynthesis and stomatal conductance in Ricinus communis L. (Castor Bean) by leaf to air vapour pressure deficit. Plant Physiol. , 99 , 1426–1434. Ku M. S. B

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B.J. , Benyon R.G. , Theiveyanathan S. , Criddle R.S. , Smith C.J. & Falkiner R.A. 1998 . Response of effluent-irrigated Eucalyptus grandis and Pinus radiate to salinity and vapor pressure deficits . Tree Physology

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Cereal Research Communications
Authors: A. Comeau, L. Nodichao, J. Collin, M. Baum, J. Samsatly, D. Hamidou, F. Langevin, A. Laroche, and E. Picard

. Vegetation of the Earth. 3 rd ed. Heidelberg Sc. Lib. p. 138. Winzor, D.J. 2004. Reappraisal of disparities between osmolality estimates by freezing point depression and vapor pressure deficit methods. Biophys. Chem

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Florida Entomol. 1990 73 601 612 Mangini, A. C. Jr. and Hain, F. P. (1991): Vapor pressure

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