پايش تغييرات پوشش گياهي و برخي ويژگي هاي فيزيكي و شيميايي خاك در منطقه مسيله قم

چكيده انگليسي :

Monitoring of changes in vegetation and soil physical chemical characteristics Case study Masileh Qom Soghra Poodineh s poodineh@in iut ac ir January 2013 Department of Natural Resources Isfahan University of Technology Isfahan 84156 83 111 Iran Degree M Sc Language Farsi Supervisors Hossein Bashari hbashari@cc iut ac ir Abstract During the years ecologists have investigated a number of factors that may control the species composition soil condition and vegetation changes in rangeland ecosystems Monitoring of vegetation and soil characteristics of these natural ecosystems is required to track range trend directions and select the best management practices accordingly The received water flow of Masileh Plain and Hoz e Sultan in Ghom Province have declined dramatically when Panzdah e Khordad Dam was constructed in 1996 over the Ghomrod River The vegetation and soil condition of these areas studied in 1996 as a part of a national research project called identifying salty land and halophyte plants This study aimed to evaluate vegetation condition and some soil physical and chemical properties of the study area in 2011 and compare these data with the 1996 To make the results of this monitoring study comparable the study area data collection procedure and time of field work in 2011 were selected relatively similar to 1996 Eighteen study sites were selected using stratified random sampling methods to cover sites with expected low to high changes in vegetation and soil conditions Plot and sampling size were determined using minimal area and statistical methods Vegetation cover percent plant density and vegetation composition were determined in all vegetation types using belt transect with 50 meters lengths and plot methods Kakridi Kent richness indices diversity indices and Shannon indices were calculated for all vegetation types in 1996 and 2011 Vegetation cover percent and the dominant shrub species density were compared in the two data series Cluster analysis was conducted between the studied sites in 1996 and the diversities between the obtained clusters were compared using ANOVA test Diversity indices also were compared in the two data series using independent t test Soil samples from the various soil horizons of one meter soil profiles were collected in all the studied sites Soil texture electrical conductivity EC sodium absorption ratio SAR pH dispersible clay content soluble sodium magnesium and calcium lime and gypsum contents of all the soil samples were measured Regression analysis was done to identify the most important edaphic factors affecting dispersible clay content as an index of soil structural instability Principal component analysis PCA was then used to evaluate the relationships of properties of different soil horizons with vegetation characteristics of the studied sites Cluster analysis was used to minimize the 81 vegetation types and 51 plant species in 1996 data set to 8 and 5 respectively using PC ORD software According to the results the vegetation condition of the study area was seriously degraded as the calculated diversity of the studied sites in 2011 was declined significantly in compare with 1996 Soil surface is become more alkaline due to the concentration of sodium and other kind of salts in soil surface of the study area Halocnemum strobilaceum was identified as the most dominant plant species in the study area followed by Tamarix spp as these plant species are well adapted to high soil pH and more alkaline soil conditions Many palatable plant species such as Aeluropus spp and Seidlitzia rosmarinus were declined or eliminated from the vegetation types due to heavy grazing pressure by camels Vegetation cover in both data series were mostly affected by soil sand percent SAR soluble sodium magnesium and calcium and the soil gypsum content Soluble sodium magnesium calcium have increased significantly in all soil horizons since 1996 According to the regression analysis results 84 3 percent of soil dis

پودينه، صغري

پايش تغييرات پوشش گياهي و برخي ويژگي هاي فيزيكي و شيميايي خاك در منطقه مسيله قم

دشت مسيله , حوض سلطان , تنوع گياهي , تجزيه و تحليل هاي چند متغيره