Parya Kamali; Reza Erfanzadeh
Volume 21, Issue 4 , March 2015, , Pages 698-707
Abstract
In the present study, the effect of soil factors on above-ground vegetation and soil seed bank diversity under grazing and exclosure conditions was studied. Soil sampling was done in winter 2010 using randomized systematic method along four transects in the grazing and exclosure areas of Vaz watershed. ...
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In the present study, the effect of soil factors on above-ground vegetation and soil seed bank diversity under grazing and exclosure conditions was studied. Soil sampling was done in winter 2010 using randomized systematic method along four transects in the grazing and exclosure areas of Vaz watershed. Along each transect, 10 plots of 1m2 were established and soil samples were collected from a depth of 0-10 cm for seed bank and physico-chemical studies. Vegetation cover was measured in each plot in late spring of 2011. Soil factors such as porosity, bulk density, relative humidity, EC, pH, nitrogen, organic matter, and stone percentage were measured. Shannon and Simpson diversity indices were calculated for above-ground cover and soil seed bank and the most important factors influencing on the diversity were specified using multiple linear regression by backward elimination method. Results showed that the porosity, bulk density and organic matter had the greatest effect on the diversity of seed bank in the exclosure area. On the other hand, EC, nitrogen, organic matter, soil bulk density and porosity were the most important factors affecting the seed bank diversity of grazing area. According to the obtained results, organic matter and nitrogen were the main factors affecting the plant species diversity in the exclosure area, while in the grazing area, physical parameters such as bulk density, porosity and stone percentage had the highest impact on species diversity.
Hamid Torang zar; Qavam aldin Zahedi; Mohammad Jafari; Hojat ... Zahedi pur
Volume 18, Issue 3 , September 2011, , Pages 384-394
Abstract
The main objective of the present study was finding spatial relationship model of the plant species composition to physico-chemical soil variability, in north-west of Mighan Desert in Arak. According to the condition of the studied habitats, the study was based on a survey of three identified vegetation ...
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The main objective of the present study was finding spatial relationship model of the plant species composition to physico-chemical soil variability, in north-west of Mighan Desert in Arak. According to the condition of the studied habitats, the study was based on a survey of three identified vegetation types. Sampling method for vegetation study was randomized systematic. Quadrate size was determined for each vegetation type using minimal area method. Soils sample were taken from 0-20 and 20-100 cm depths. The measured soil factors included, EC, organic matter, texture, lime, gypsum, available moisture, pH, and soluble ions (Ca2+, Mg2+, Na+, Co32- , H-Co3, Cl-, So42). The classification of vegetation was analyzed by TWINSPAN and DCA methods. To determine the most edaphically effective factors in distribution of vegetation, PCA and CCA were applied. Three main vegetation groups were identified by TWINSPAN analysisand DCA. The result indicated that soil salinity, soil texture, lime, and soluble ions (Mg2+, So42) played the main role in the distribution of plant species.