Sahar Samadi Khangah; Mehdi Moameri; Masoome Abbasi Khalaki
Abstract
The aim of this study was to investigate the ecological factors affecting the distribution of four Trifolium repense, T. pratense, T. micranthum and T. compestre species in Fandoghlou rangelands of Namin county in Ardabil province. Sampling was conducted in six sites with the presence and absence of ...
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The aim of this study was to investigate the ecological factors affecting the distribution of four Trifolium repense, T. pratense, T. micranthum and T. compestre species in Fandoghlou rangelands of Namin county in Ardabil province. Sampling was conducted in six sites with the presence and absence of species at random. Topographic, climatic, land cover and density of selected species were recorded. From each transect, soil samples were taken from the root activity depth the parameters of acidity, electrical conductivity, soil texture, lime, calcium, magnesium, sodium, phosphorus, potassium, organic matter, propagated clay and soil moisture content were measured. A significant difference was observed between the environmental factors on presence and absence of studied species by one-way ANOVA and comparison of the mean of the measured characteristics with Duncan test. To determine the importance of the variables in different sites and the species distribution, Linear Discriminant Analysis (LDA) was used. Results showed that there were significant different between the factors of electrical conductivity, slope, sodium, organic matter (p<0.01) and factors of elevation, rainfall, temperature, acidity, potassium, phosphorus, clay, silt, dispersible clay and bare soil (p<0.05) in sites of presence and absence of species. According to the results of the LDA, four functions were justified as 78.50, 15.60, 5.80, 0.10 %, respectively and totally 100% of the total variance of the data were justified. Four factors (temperature, electrical conductivity, potassium and clay) were identified as the most important factors in the distribution of the T. repense, T. pratense, T. micranthum, T. compestre species.
Reza Yari; Esfandiar Jahantab; Gholam Ali Heshmati
Abstract
Given the importance of having data on vegetation and soil in different geographical aspect, the aim of this study is the assessment the geographical aspect's impact on Functional Potential and soil surface indicators in Chhar-Bagh Summer Rangeland, Golestan province. For the study used the method Landscape ...
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Given the importance of having data on vegetation and soil in different geographical aspect, the aim of this study is the assessment the geographical aspect's impact on Functional Potential and soil surface indicators in Chhar-Bagh Summer Rangeland, Golestan province. For the study used the method Landscape Function Analysis (LFA) and main Geographical aspect. For this purpose, in the four main geographical aspect, three transects 100,m were established and along the transects type, length and width patches and interpatches were measured. To calculate the Functional Potential (Soil Stability, Infiltration and Nutrient Cycling and and Vegetation Organization Index). To investigate the functional significance potential of SAS Software and ANOVA, for mean potential functional classification of Duncan Test used. To investigate the soil surface along each transect, 5 plots and 11 indicators way quality and using the scoring tables and to check the normality of the data, the Kolmogorov-Smirnov test was used. To investigate the significance Kruskal-Wallis nonparametric test and classification of soil surface indicators grouped Duncan test was used. The results showed a significant difference between the functional potential in different geographical aspects (P> 0.05), So that the highest percentage of functional potential to the north and lowest in the East was estimated. Vegetation organization index for geographical aspects North, South, East and west were respectively 0.53, 0.43, 0.38 and 0.51. The results showed that except cryptogam cover and Micro-topography indexes, all indicators were significant in different geographical aspects (P> 0.05).
fatemeh naghizadeh; mohammad jafari; hosein azarnivand; Mohammad Ali Zare Chahouki
Abstract
In this study, the role of soil properties in making difference between plant communitieswas examined. First, four plant types were identified, including Pteropyrumaucheri-Salsolarigida، Astragalus gossypinus - Acanthophyllum herateens، Amygdalus scoparia – Achilla millefolium and Ephedra intermedia ...
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In this study, the role of soil properties in making difference between plant communitieswas examined. First, four plant types were identified, including Pteropyrumaucheri-Salsolarigida، Astragalus gossypinus - Acanthophyllum herateens، Amygdalus scoparia – Achilla millefolium and Ephedra intermedia – Erigon capestra, through randomized systematic sampling and field survey in representative area of each type. In each plant type, three 500-meter transects were selected and in each transect, ten plots were placed along each transect. Characteristics of vegetation such as type and percentage of cover, gravel percentage, litter percentage and bare soil percentage were determined within each plot. In addition, in order to study the soil properties, at the beginning and at the end of each transect, a profile was dug and soil samples were taken from the depths of 0-20, 20-80 cm. Soil physical and chemical properties (texture, pH, electrical conductivity, organic matter percentage, gypsum percentage, lime percentage, salts such as sodium, potassium, calcium and magnesium, sodium absorption ratio, sodium exchange percentage) were determined in soil laboratory. Then, the role of soil properties in making difference between plant communitieswas determined by using ANOVA statistical analysis, and the key factors making this difference were introduced as sand percentage, organic matter percentage, and electrical conductivity.
Mohsen Armin; hasan rouhipour; Hassan Ahmadi; Ali Salajegheh; mohammad Hossein Mahdian; vajihe ghorban nia kheybari
Abstract
Knowledge of soil components controlling aggregate stability is very important to soil structure conservation. Also, identification of the critical soil properties affecting aggregate stability is central to understanding where erosion might be located within a catchment as a result of natural patterns ...
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Knowledge of soil components controlling aggregate stability is very important to soil structure conservation. Also, identification of the critical soil properties affecting aggregate stability is central to understanding where erosion might be located within a catchment as a result of natural patterns in aggregate stability. The objective of this study, which was carried out in surface soils from Taleghan, was to relate aggregate stability to selected soil properties. In this study, based on homogeneity in slope, aspect and lithology work units were prepared, and then by relying on results of geostatistical studies in homogeneous work units in soils of Taleghan watershed, with 3260 hectares in area, 84 points as the soil sampling points were selected. The indices of stability used are the mean weight diameter (MWD) and wet aggregate stability (WAS). Correlation between mean weight diameter and measured properties were extracted using Pearson correlation coefficient and evaluated in terms of their statistical significance. Then based on the results of correlation and using stepwise regression, models of aggregate stability prediction were developed. The unexpected results have been obtained from correlation between soil properties and aggregate stability so that the correlation between aggregate stability and the percentage of Caco3, clay and saturation are negative while that with fine sand and very fine sand are positive. Thus the improvement of aggregate stability and soil erosion control in Taleghan watershed depends on management of these soil properties and soil conservation projects in order to adjust and optimize them
Hamid Toranjzar; Asghar Zare Chahouki
Abstract
Geostatistical approaches have great importance because they include spatial correlation of geographic data. Present study evaluated the efficiency of geostatistical techniques and demonstrated their capabilities in studying the soil variables(soil texture (sand percent), EC and So4-2) in the important ...
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Geostatistical approaches have great importance because they include spatial correlation of geographic data. Present study evaluated the efficiency of geostatistical techniques and demonstrated their capabilities in studying the soil variables(soil texture (sand percent), EC and So4-2) in the important plant community of Nitraria schoberi in Meighan desert, Arak. A regular grid on the map comprising rectangular cells was designed and situated over the experimental area with 98 points for vegetation type. The grid was laid out in the field using the global positioning system. Soil samples were taken between 0-20 and 20-100 cm layers for each point. Analysis using the best view at semivariogram model were applied to select the Gaussian models of soil characteristics with R2 higher than 0.95. Among ordinary Kriging, simple Kriging and Inverse distance weighting methods, ordinary kriging method showed the best cross-validation criteria (mean square error and average error) and had higher prediction accuracy than others. Finally, spatial estimates of the soil characteristics were performed using ordinary kriging.
