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Amiri et al

Greener Journal of  Physical Sciences Vol. 2 (4), pp. 141-147, October, 2012.

ISSN: 2276-7851 © 2011 Greener Journals

Research Paper

Turbulent Velocity Fluctuations as Affected by Biotic and Abiotic Windbreaks under Field Conditions

Iraj Amiri¹, Javad Taei²*, Mohammad Reza Ekhtesasi³

and Ali Reza Shahryari⁴

¹Department of Natural Resources, Faculty of Agriculture, University Of Jiroft, Jiroft, Iran

²Department of plant sciences, Faculty of Agriculture, University Of Jiroft, Jiroft, Iran

³Faculty of Natural Resources, Yazd University, Yazd, Iran

⁴Faculty of Natural Resources, University Of Zabol, Zabol, Iran

*Corresponding Author’s E-mail: ga_agric @yahoo. com

Abstract:

Windbreaks have been used for centuries to shelter crops from wind damage and to protect soils from wind erosion. This study was performed in 5 steps to evaluate the effects of biotic and abiotic windbreaks on mean horizontal flow and turbulent velocity fluctuations under field conditions. These steps included granolometery analyzing, determination of field threshold velocity of soil erosion, estimation of acceptable wind speed, optimizing windbreak distance and wind speed recording. Two kinds of windbreaks were used in this study, biotic windbreak (Tamarix aphylla) with 45% density and abiotic windbreak (Mud wall) with 100% density. Results of field experiment showed that optimized distances for abiotic and biotic windbreak are respectively observed at 7.87h and 4.5h after windbreak. Finally mud wall is applicable for high decreasing wind speed at the back of windbreak but its high wind speed fluctuation and high turbulence were limited to these windbreaks in agro ecosystem. Tamarix aphylla with 45% density is applicable for medium decreasing of wind speed and creating low turbulence after windbreak.

Keywords: Mud wall, Tamarix aphylla, threshold velocity, windbreak, Wind.

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Journal Name : citation_journal : Greener Journal of  Physical Sciences

Publication Status/Date : usp_status_date : October, 2012