sadat feiz nia; Faranak pourtayeb; hasan ahmadi; kourosh shirani
Volume 22, Issue 4 , March 2015, , Pages 695-710
Abstract
In determining the source of sediments in the basins, fingerprinting technique has been taken into consideration by researchers mainly because of the many problems in applying traditional methods. In the above-mentioned method, the share of source areas in sediment production is determined using the ...
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In determining the source of sediments in the basins, fingerprinting technique has been taken into consideration by researchers mainly because of the many problems in applying traditional methods. In the above-mentioned method, the share of source areas in sediment production is determined using the right combination of separator properties of sedimentary source. The tracers used in this research included P, Na, Ca, Mg, Pb, Cu, Cd, Co, Se and Mn. Co and Cu were selected as suitable combination using discriminant analysis. Finally using this combination and combined multivariate models, the share of six lithological units including Klsol, Omql, TRn, Murmg, Qcf and Mlgs in the sediment production was calculated to be 43.97, 19.62, 15.94, 11.24, 3.31 and 2.32 %, respectively.
Mohsen Padyab; Sadat Feiz Nia; Mohammad Nohtani; Hasan Ahmadi; Ardashir Shafiei
Volume 20, Issue 3 , November 2013, , Pages 345-453
Ali Ehsani; Hosein Arzani; Mahdi Farahpoor; Hasan Ahmadi; Mohammad Jafari; Adel Jalili; Hamid Reza Mirdavodi; Hamid reza Abbasi; Mojgan Azimi
Volume 14, Issue 2 , January 2007, , Pages 249-260
Abstract
The effects of climatic factors on four dominant range land species of Markazi province, Iran, were studied. Species were Artemisia sieberi, Salsola rigida, Noaea mucronata, Stipa barbata and were monitored from 1998 to 2005. Site is located in steppe lands and called Nemati range, Akhtarabad of Saveh. ...
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The effects of climatic factors on four dominant range land species of Markazi province, Iran, were studied. Species were Artemisia sieberi, Salsola rigida, Noaea mucronata, Stipa barbata and were monitored from 1998 to 2005. Site is located in steppe lands and called Nemati range, Akhtarabad of Saveh. Climatic factors were annual rainfall, rainfall of grazing season plus rainfall of previous year, temperature, solar radiation and wind velocity. Among the main indicators, as results shows, growing season plus previous rainfalls is the most effective indicator on forage production with high and significant correlation. Total yield have positive and significant correlation with growing season rainfall and previous rainfall as well as production of Artemisia sieberi, Salsola rigida. Soil and water regime in dry and semi-dry areas, in growing season, is in a way that plants are dependent on stored moisture. Shrubs, with their deep roots, are more capable of using this moisture. Therefore stored moisture could be known as an indicator of rain quantity. Result of this research showed that rainfall indicator in growing season and previous season is a variable that plays fundamental rule in production, showing a linear relationship. Negative correlation was shown between number of sunny days, total yield and yield of two species, Salsola rigida and Artemisia sieberi.
Mohammad Jafari; Fatemeh Panahi; Hasan Ahmadi; Hamid reza Abbasi; Mohammad Musavi; Mohammad ali Zare; Ali Tavili
Volume 13, Issue 3 , February 2006, , Pages 278-283
Abstract
The desertification phenomenon with all the problems it causes , most great effect will remain in soil, so by assessing soil variations we can reach the intensity of desertification. In the Iranian model for desertification assessment some indices including EC, soil depth, soil texture and the amount ...
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The desertification phenomenon with all the problems it causes , most great effect will remain in soil, so by assessing soil variations we can reach the intensity of desertification. In the Iranian model for desertification assessment some indices including EC, soil depth, soil texture and the amount of subsoil gravel are recommended in order to assess the intensity of desertification. Here, we chose fields in different environments such as Soleyman, low desertification risk, Gazeran, desertification risk & Hossein Abad Mish Mast, already desertified field. We selected 5 profiles in each station and studied topsoil and subsoil layers in each profile and measured soil’s physical and chemical properties in the laboratory. We used spilt plots design to regard different properties of soil in each station in topsoil and subsoil and their effects on each other. In order to appoint the desertification potential in each area and in each soil unit we used the formula following: where x is score of soil indicator and x are scores of Ec, depth, and texture and subsoil gravel rate. The obtained results based on this formula indicate that the desertification of each area is moderate. Statistical analysis showed a meaningful difference for gravel and texture. The results of Duncan test selected Soleyman and Gazeran stations in one unit subset. The method used here is designed according to soil information bank and apt to arid and semiarid climate. Of its defects we can point the unreality of its scoring because there is just 4 degrees for the intensity of desertification which limits the range of scoring. Certainly in order to evaluate the desertification phenomenon we should match the results with other sections’ results. Their results will help to precede the desertification evaluation and present indices fit to Iran pattern and conditions.