Showing 8 results for Landscape
H. Khademi, H. Khayyer,
Volume 8, Issue 2 (7-2004)
Abstract
Understanding the variability of pedological properties as well as the soil quality attributes on different landscape positions in hummocky terrains would result in a better land management in such areas. Despite the importance of such studies, no research has been couducted on the landscape-scale variability of soil quality indices in Iran and most researchers have so far focussed on pedological aspects of soil variability. The objective of this study was to understand the variability of selected soil quality indices at different landscape positions. A systematic grid including 120 points (12x10) with a distance of 30m was laid out in a hummocky rangeland around the city of Semirom. Surface soil samples were taken from 120 points on grid nodes and their organic carbon, microbial respiration rate, phosphatase activity, pH and EC were measured. Also, the thickness of A horizon and the soil moisture content were measured on grid nodes in the field.
The results indicated that the lower slope positions including footslope and toeslope had the highest amount of phosphatase activity, microbial respiration, A horizon thickness, organic carbon, and EC. In contrast, soils occuring on shoulder had the least amount of the above-mentioned properties. Soils on summit and backslope seem to have been moderately degraded. Soil pH showed the opposite trend, as compared to other properties studied. The presence of a great variability in soil quality attributes at the landscape scale can be attributed to differenes in effective moisture that various landscape positions receive, as well as the differenes in soil erosion and deposition rates. This can also be an indication of a severe land degradion due to poor management practices. Since applying different management practices on different landscape positions are practically impossible, to be on the safe side, it is highly recommended to plan conservation practices based on soil quality of the most degraded landscape positions.
Sh. Ayobi, M. H. Alizadeh,
Volume 10, Issue 2 (7-2006)
Abstract
Conventional soil survey methods for soils within the watersheds in Iran require a significant budget with many soil surveyors and much time. Additionally, no accurate and reliable information exists on the spatial variability of superface soil parameters in order to predict the soil loss by different models (RUSLE, PISAC, EUPOSEM, MORGAN). Also information on planning and management activities is lacking. These limitations call for methods of estimating soil properties using minimum sampling derived from important terrain parameters. This study was performed to develop soil-landscape models in three geological units (E2Sc, Ku, Plc), in a part of Mehr- watershed, Sabzevar. Six soil variables selected for this study were topsoil clay, gravel, sand, organic matter content, field capacity and bulk density measured at 316 sites on a regular 100m grid. Topographic attributes were calculated by a digital elevation model with 100m spacing. Finally, multiple linear regression analyses relating soil to topographic attributes were performed and then models were validated by additional sample points (78 of 316). The developed regression models showed significant relationships between surface soil properties and topographic attributes such as elevation, slope, aspect, wetness index, stream power index and sediment transport index. The mean errors and root mean square errors in the validation of the models were low and acceptable. The regression equations could explain only 26 to 72 % of the variability measured in the soil attributes in the watershed scale with 100m spacing.
N. Toomanian, H. Khademi , A. Jalalian,
Volume 12, Issue 44 (7-2008)
Abstract
Determination of landscape evolution is useful to well understand the physical environment and it also enables us to conduct the soil related studies. The objective of this study was to establish the historic evolution of Zayandeh-rud Valley from late Tertiary to Quaternary. To achieve this objective, the spatial structure of a representative area of Zayandeh-rud Valley in three dimensions was examined. Responsible geologic and geomorphic processes of landscape formation were determined and inherited records and evidences of changes in soil development were investigated. The inherited foot marks and different analyses proved that following the Zayandeh-rud River formation, from Miocene to present time, the following processes and events have occurred during valley formation pathway: 1- formation of old gypsiferous gravelly alluviums, 2- lagoon formation, the change in the river pathway, 3- playa formation, 4- river terrace deposition and 5- starting of wind erosion.
A Soffianian, S Maleki Najafabadi, V Rahdari,
Volume 13, Issue 49 (10-2009)
Abstract
Landscape ecology as a modern interdisciplinary science offers new concepts, theories, and methods for land evaluation and management. One main part of landscape ecology is describing patterns in the landscape and interpreting the ecological effects of these patterns on flora, fauna, flow of energy and materials. Landscape studies require methods to identify and quantify spatial patterns of landscape. Quantification of spatial patterns is essential to understand landscape functions and processes. Landscape indices as diversity and naturalness can provide quantitative information about landscape pattern. Remote sensing and GIS techniques have high ability for landscape researchers to specify, map and analyze landscape patterns. The objectives of the research include mapping and quantifing diversity and naturalness indices for Mooteh wildlife refuge by land use/land cover map derived from remote sensing images. Finally, diversity and naturalness were classified in 4 and 6 classes, respectively. Results showed that the intermediate and high diversity classes (class 1 & 2) have occupied the largest area in the study area. Among naturalness classes, class 1 which represents the high level of naturalness has taken the largest area in Mooteh W.R.
M. Zeraatpisheh, Sh. Ayoubi, H. Khademi, A. Jafari,
Volume 23, Issue 1 (6-2019)
Abstract
Landscapes are considered as a series of different land units with a size, shape and location arrangement that are permanently under the influence of natural events and human activities. Understanding the dynamics and heterogeneity of landscapes and environmental changes is of great importance. In order to quantitatively analyze and interpret the factors affecting the changes in the environment and terrain diversity, diversity indices were used to analyze the ecosystem. In this study, the relationships between soils evolution and geomorphic surfaces were investigated by applying pedodiversity indices in a part of a semi-arid region of Chaharmahal-Va-Bakhtiyari Province. In the studied area, three orders were recognized: Mollisols, Inceptisols, and Entisols. The results showed that soil evolution in the studied area was mostly influenced by topography, parent material and the underground water level; that is, in the higher lands, the lowest evolution was observed while in the plain ones, the soil of the higher evolution observed. In addition, the effect of geomorphic surfaces were obvious. Pedodiversity indices increased under the decrease of the hierarchy levels. In addition, the obtained equations revealed the nonlinear relationships in the area of geomorphic surfaces. The positive and nonlinear relationship between pedodiversity indices confirmed the nonlinear dynamic system in the studied soils.
H. Aalipour, A. Nikbakht, N. Etemadi, M. Soleimani, F. Rejali,
Volume 23, Issue 2 (9-2019)
Abstract
Trees decline is a complex physiological disease that results from the interactions between several factors, one of which is heavy metal stress that ultimately leads to the death of trees. This experiment, which was conducted during 2016-2017 at the campus facility of the Department of Horticulture at Isfahan University of Technology, was conducted to investigate the effects of inoculation with arbuscular mycorrhizal fungi (AMF) (Rhizophagus intraradices and Funneliformis mosseae inoculated, and the combination of both species) and plant growth promoting rhizobacteria (PGPR), Pseudomonas Flourescens, on the growth responses of Arizona cypress (Cupressus arizonica G) to different concentrations of cadmium (0, 5, 10, 15, 20); this was done as a factorial experiment based on a completely randomized design, with three replications. The interactions between AMF, PGPR, and cadmium on potassium and iron concentration, height, and dry weight of Arizona cypress seedlings were significant. By increasing the concentration of cadmium in most of the treatments, the colonization, phosphorus, potassium and iron concentrations, height and dry weight of the shoot Arizona cypress seedlings were decreased, while the percentage of electrolyte leakage and proline content were increased. The AMF-inoculated plants increased phosphorus, potassium and iron concentrations, Height, shoot dry weight, proline content and reduced electrolyte leakage percentage, as compared to non-mycorrhizal (control) plants. In plants inoculated with both microorganism (mycorrhizal fungi and Pseudomonas), there was a positive effect regarding the concentration of nutrients such as potassium and iron; there was also the improvement of growth characteristics such as height and dry weight of the seedlings, as well as the appearance and freshness of the plant. The results, therefore, showed that inoculation of Arizona cypress seedlings with the combination of mycorrhizal fungi and Pseudomonas fluorescens bacteria could have a positive effect on the growth and survival of this tree under Cadmium stress condition.
P. Shojaei, M. Gheysari, H. Nouri, H. Esmaeili, S. Eslamian,
Volume 23, Issue 3 (12-2019)
Abstract
Creation and conservation of urban parks is challenging in arid environments where daily thermal extremes, water scarcity, air pollution and shortage of natural green spaces are more conspicuous. Water scarcity in the arid regions of Iran is major challenge for water managers. Accurate estimation of urban landscape evapotranspiration is therefore critically important for cities located in naturally dry environments, to appropriately manage irrigation practices. This study investigated two factor-based approaches, Water Use Classifications of Landscape Species (WUCOLS) and Landscape Irrigation Management Program (LIMP), to measure the water demand in a botanic garden. The irrigation water volume applied was compared with the gross water demand for the period from 2011 to 2013. On average, WUCOLS estimated an average annual irrigation need of 1164 mm which is 15% less than the applied value of 1366 mm while the LIMP estimate of 1239 mm was 9% less than the applied value. Comparison of estimated and applied irrigation showed that a water saving of 9% can be made by the LIMP method. The outcomes of this research stressed the need to modify the irrigation requirements based on effective rainfall throughout the year, rather relying on long-term average data.
S. Mehri Babadi, M. Afyuni, Sh. Ayoubi,
Volume 24, Issue 1 (5-2020)
Abstract
For sustainable soil management, the effects of slope position and land use change on soil and water resources are essential. In this research, three land uses including degraded pasture, drought and apple gardens were selected to determine the effect of slope position and land use on some physical and chemical properties of soil in the Koohrang area of Chaharmahal and Bakhtiari province. Each of the applications was divided according to the position of the slope, and from three applications and organic matter (OM), saturated hydraulic conductivity (Ks), water repellency (RI), dispersible clay (DC) and weighted average aggregate diameter (MWD) were studied as the physical and chemical properties of soil. The results showed that Ks had the greatest coefficient of variation. Also, the results of the mean comparison revealed that all of the measured physical and chemical properties had a significant difference in different slope applications and positions at 5% level. In general, the garden and the base position of the slope had better qualitative conditions than other land uses and slope positions. Rangeland degradation and change in the use of pasture from dryland cultivation led to a decrease in soil quality, which could reduce soil utilization and exhaust some of the land from the production cycle. The results of the correlation between chemical and physical properties of soil showed that in general soil organic matter had the highest correlation with other parameters.
