فهرست مطالب mohammad hady farpoor

Mineralogical composition, soil morphological properties, and magnetic susceptibility were affected along soil evolution in soils. That is why micromorphology helps in performing soil classification and evolution studies, as well as making soil management practices much more efficient. Clay mineralogy is a useful tool that helps in better understanding soil forming factors and processes. Soil magnetic properties are complex reflections of chemical, geological, and biological soil characteristics. Thus, knowledge about factors affecting magnetic susceptibility can help in better understanding and interpreting the results obtained in an area. Assessment of soil magnetic behavior might be used in pedology, soil mapping, investigation of soil process variations, parent material composition, sedimentary processes, soil drainage conditions, soil pollution, and separation and identification of soil unit boundaries. The present study was performed to investigate the effects of magnetic susceptibility, clay mineralogy, and micromorphology on soil characteristics, genesis, and evolution.

Seven representative pedons were selected in sedimentary and igneous sections in uncultivated land use and physiographic units: hill, piedmont plain, alluvial plain, and lowland. Physicochemical properties measurements were performed on the collected samples from representative pedons using standard methods. The pedogenic (Fed) and amorphous (Feo) iron concentrations of the extracts were determined using a Vario Atomic Absorption Spectroscope (AAS) instrument. Undisturbed soil samples were selected for micromorphology studies and thin section preparation. Additionally, three soil samples were used for X-ray diffraction (XRD) analyses after carbonates, organic matter, and Fe were removed using Jackson (1965) and Kittrik and Hope (1963) procedures. Finally, the mass-specific magnetic susceptibility of soil samples was determined using a Bartington MS2 meter equipped with the MS2B Dual Frequency sensor, capable of taking measurements at both low (χlf at 0.46 kHz) and high (χhf at 4.6 kHz) frequencies.

Salinization, leaching, and illuviation processes of gypsum and carbonates were observed in the studied pedons. The soils were classified as Aridisols (Soil Taxonomy system) and Solonchacks, Solonetz, Gypsisols, and Calcisols RSGs (WRB system) due to the presence of calcic, gypsic, salic, argillic, and natric diagnostic horizons. The presence of gypsum, carbonates, salt, clay accumulation, and argillic horizon reduces χlf values. The calcite coating located on the clay coating could probably be attributed to the presence of a climate with more available humidity in the past. The range of soil magnetic susceptibility was from 4.3×10-8 to 1264×10-8 m3kg-1. Gypsum infillings, different forms of gypsum, clay accumulation and coatings, and weathered calcite crystals were among the dominant micromorphological features observed in the studied pedons. Montmorillonite, chlorite, illite, kaolinite, quartz, and vermiculite minerals were observed in the studied pedons. Chlorite and illite minerals were dominant in the clay fraction of the studied soils, whereas a portion of these minerals was probably converted to vermiculite. Discontinuities observed in pedon 2 could be accounted for as proof of more available humidity in the past compared to the present time periods. Moisture has caused the removal of potassium and transformation of illite and chlorite to vermiculite. The dominance of illite and chlorite can be proof of initial weathering and evolution in the other studied pedons.

The χlf variations was related to depth trend and physicochemical properties. The χlf values showed a noticeable negative correlation with argillic horizon, gypsum content, carbonate calcium, and salinity. It seems that most of the clay minerals originated from the parent material in the present study, and pedogenic source has rarely taken place. Besides, the χlf and Fe contents were directly correlated. In general, the results indicated young soils with primary development stages in the area under study. Pedon 2 with buried polygenetic soils is an exception.

For better management of gypsiferous soils, it is essential to have knowledge about distribution and its various characteristics. The objectives of the present research included soil genesis studies, classification, micromorphology and clay mineralogy of gypsiferous soils in Jiroft and Anbarabad regions, located in the south of Kerman Province. For this purpose, seven representative pedons were selected, described and sampled. Routine physicochemical, micromorphological and clay mineralogy analysis were performed on the soil samples. Finally, the soils were classified according to two systems: Soil Taxonomy (2014) and WRB (2015). The origin of gypsum in the soils of the studied area was gypsum marl formations at altitudes. Soils of the region were classified using Soil Taxonomy system in two suborders of gypsids and salids, and classified according to the WRB in three soil reference groups of Gypsisol, Solonchak and Slonetz. Coating and lenticular gypsum crystals and clay coating were observed in the thin sections of the studied soils. Lenticular gypsum crystals were observed in fine-textured soils. The clay coatings observed in the natric and argillic horizons were due to the role of sodium dispersion and paleoclimate, respectively. Illite, chlorite, smectite, kaolinite, sepiolite and palygorskite clay minerals were found in the soils of the regions. The presence of gypsum in the soil and evaporitic formations in the area caused the formation of palygorskite and sepiolite minerals in the soil. An inverse relationship was found between the amount of palygorskite and sepiolite with the amount of smectite, so that due to more weathering in the more humid paleoclimate and with reducing the amount of gypsum, the amount of smectite increased and that of palygorskite and sepiolite minerals decreased.

The present research performed to investigate soil evolution in soils developed on sedimentary and igneous parent materials, northern Kerman. Four representative pedons were selected. Physicochemical properties and Micromorphological features investigated in soil samples. The principal oxides content measured using ICP-OES. Color, clay accumulation, Fe content, and geochemical indices were used to assess soil development in the studied pedons. Studied profiles classified in Aridisols order and Calcite, Gypsic and Argillic horizons were dominant. Mean of pedogenic, free, crystalline, and active Fe contents were determined as 9.4, 0.5, 8.8 g/kg and 0.06, respectively. The values of clay and Fe accumulation indices were obtained 17 (in pedon 3) to 76.5 (in pedon 2) and 24344 (in pedon 2) to 2788 (in pedon 3), respectively. The results showed the correlation between Fe contents and color indices at the 99% level. The mean weight of principal oxides noticeably increased in pedons 1 and 3 compared to other studied pedons. All of geochemical indices, except WIP, showed higher weathering in pedons 1 and 3.The results of color, Fe oxides and clay accumulation and CIW, CIA, PWI, V, PIA, STI and R geochemistry indices demonstrated higher evolution of pedon 3 compared to other studied soils. No significant difference in development rate reated to parent materials change was found. Likely, various evolution of studied pedons was due to intractions among geochemical indices and soil-forming factors and processes.

Climate and topography are two important soil-forming factors that affect the genesis, evolution, and classification of soils. Topography may influence soil evolution through attributes such as the direction, shape, and percentage of the slope, the amount of precipitation, penetration, and runoff, the rate of erosion, as well as the difference in the drainage conditions. On the other hand, organic carbon, the amount and type of clay, soil color, calcium carbonate, base saturation, leaching depth, and solubility of salts in the soil are closely related to the climate. Hence, this study aimed to investigate the effect of climate and topography on changing physicochemical, mineralogical, and micromorphological properties of soil.

This research focused on two regions including, Sardooeyeh and Bam. The Sardooeyeh region, with the soil moisture-temperature regime of xeric-mesic, is about 3500m above sea level. However, the mean elevation in the Bam region, with the aridic-thermic regime, is 900m. Eight representative pedons on the extrusive igneous parent material with an intermediate composition were selected, sampled, and described. Physicochemical, mineralogical, and micromorphological analyses performed on the soil samples, and the soils were classified using Soil Taxonomy and World Reference Base for Soil Resources (WRB). Soil pH, particle size distribution, electrical conductivity, equivalent calcium carbonate, cation exchangeable capacity, and gypsum were measured, then eight samples were selected for clay mineralogy investigations. A Bruker Dh8 Advance X-ray diffractometer at 30 mA and 40 kW was used to analyze the samples. Scanning electron microscopy was performed. The undisturbed soil samples from horizons were selected for micromorphological observations.

The results revealed the increase in the clay percentage, cation-exchange capacity, organic carbon, and equivalent calcium carbonate in the elevations with the xeric regime. On the other hand, an increase in the amount of electrical conductivity and gypsum percentage in the aridic regime was determined. Thus, changes in soil properties caused different soils, including a range of Mollisols and Alfisols (xeric regime) to Aridisols (aridic regime) in the Soil Taxonomy and the Chernozems, Luvisols, and Calcisols (xeric regime) to Solonchaks, Gypsisols and Cambisols (aridic regime) in the WRB system to be classified. One of the strengths of the WRB system compared to the Soil Taxonomy is the classification of buried soils and the use of the "Raptic" qualifier to indicate the lithologic discontinuity within the pedon. The results of clay mineralogy elucidate the presence of illite, palygorskite, chlorite, smectite, kaolinite, vermiculite, smectite-vermiculite interstratified minerals, and quartz. In the xeric regime, the illite mineral decreased, and vermiculite and smectite increased. However, the amount of illite increased in the aridic climate. Furthermore, the simultaneous presence of palygorskite and smectite-vermiculite interstratified minerals can be the result of the presence of polygenetic soils in this region. Calcite infilling, nodule, and calcite internal hypo-coating, with clay coatings, clay bridges, and link clay capping were among the dominant micromorphological pedofeatures observed in the xeric moisture. On the other hand, the simultaneous presence of calcite and clay coatings and infillings together with gypsum infillings and the interlocked gypsum plates prove the role of paleoclimate in soil formation.

Results of this study showed that the current climate, the paleoclimate prevailing in the region, and topography have key roles on the intensity of weathering, the amount of clay minerals, and the type of pedofeatures in the region. Besides, due to the lack of carbonate in the parent material, it seems that the increase of weathering in the xeric regime part of the area significantly influenced on the alteration of plagioclase mineral which in turn, increased secondary calcium carbonate.

Rheological characteristics of soils (including their deformation and flow behaviors when subjected to external stress) can provide important information on microstructural and microaggregate stability. One of the newest methods of assessing the stability of aggregates is the use of rheometric discussions in this regard. In other words, rheometry can be used to evaluate the elastic behavior of soil versus its plastic behavior in a range of aggregate deformation and thus a more quantitative interpretation of aggregate formation or stability against stress. In the last decade, Amplitude sweep test (AST) has been used to evaluate the stability of soil microstructure and its elastic behaviors. The present study was designed to determine the aggregate stability and viscoelastic behavior of the soil using the rheometric method. In the present study, physical, chemical, clay mineralogical properties and classification of dominant soil orders in Chaharmahal-va-Bakhtiari Province were studied and compared in order to determine the stability of aggregates and viscoelastic behavior of soils using the rheometric method.

Five different soil orders were described and sampled in Shahrekord, Farsan, and Koohrang cities. After air-drying and sieving of soil samples taken from the genetic horizons, the physical and chemical properties were measured using standard methods. Besides, the type of clay minerals was determined by the X-ray diffraction method. AST was used to quantify the initial rheological parameter values, including the storage (G') and loss moduli (G"), deformation limit (γL: when the material begins to irreversibly deform), deformation at flow point (γf: when the material becomes viscous), loss factor (tan δ = G''/ G') and integral z (which summarizes the overall elasticity of the material) in order to study microstructural stability and microaggregates of the five soil orders. Finally, the correlation diagram was plotted among soil properties and rheological parameters using R software. Besides, the soil was classified based on the American Soil Taxonomy (2014) and WRB (2015).

The studied pedons classified based on the American Soil Taxonomy (2014) and WRB (2015) in five different soil orders and four reference soil groups, including Entisol (Cryosol in WRB), Vertisol, Mollisol (Kastanozem in WRB), Alfisol, and Inceptisol (Calcisol in WRB). Semi-quantitative analysis of clay minerals showed that the soils have different clay minerals assemblage including kaolinite, vermiculite, smectite, illite, chlorite, and quartz. The results of the AST indicated that the deformation limit was significantly higher in subsoil horizons than topsoil horizons and was also higher in the clayey soils compared to sandy soils. The soils with “vertic soil properties” showed the high range of linear viscoelastic region (LVE) that attributed to the samples with high elasticity behavior. Soils with higher clay contents and further evolution showed higher rheological parameters, implying that these soils had more rigid microstructures incomparable with other soil orders which in turn, indicated the higher microstructural and microaggregate stability. In contrast, the horizon, which had high sand content and little soil development, had the lowest values for all properties, thus indicating a lack of micro-aggregate stability. Pearson correlation coefficient analyses revealed that integral z was influenced by soil physicochemical properties, and was higher in soils with the clay fraction dominated by expansive clay minerals and higher cation exchange capacity.

Altogether, the rheological parameters indicated that more developed soils had greater microstructural stability than their less-developed counterparts. As a result, rheological measurements may be useful for identifying the major factors that affect soil aggregation. In addition, these parameters can be used as indicators to evaluate the relative amount of soil evolution in future studies.

Introduction Landscape represents a large portion of land/terrain that is either formed by a repetition of similar or dissimilar relief/molding types or an association of dissimilar relief/molding types (e.g., valley, piedmont, mountain, etc.). It is usually affected by a set of natural (e.g., climate, organisms, parent material, topography, time, erosion, sedimentation, etc.) and/or artificial (e.g., artifacts) factors. Soil is one of the most important components of landscape that is affected by various factors such as water and wind. Aeolian or alluvial sediments (from seasonal rivers) in arid areas cause the formation of different landforms and change the landscapes in these areas. Therefore, the study of geoforms in arid regions can lead to a better understanding of geomorphological processes and soil change in these areas. There are various methods, including soil micromorphology and clay mineralogy, to understand the alteration of landscapes and the soils change on them. The aim of this study was to investigate the physical and chemical properties, clay mineralogy and micromorphology of soils in various geomorphic units of Davaran Region, Rafsanjan. Materials and Methods Seven dominant geomorphic units (geoforms) of the region, including pediment, margin of fan and cultivated clay flat, alluvial fan, desert pavement, margin of pediment and sand sheet, active drainage, margin of fan and uncultivated clay flat were selected using Google Earth images and field studies. Nineteen pedons were excavated and described in the geomorphic units. After selecting a representative pedon in each of the geoforms, their genetic horizons were sampled. Besides, in order to conduct soil micromorphology studies, undisterbed and oriented samples were collected from selected horizons. After transferring the samples to the laboratory, their physical and chemical properties were measured using standard methods. In addition, clay mineralogy studies were performed by X-ray diffraction method and micromorphological studies were done using a petrographic microscope. Finally, soil classification was performed based on both Soil Taxonomy (2014) and WRB (2015) systems. Results and Discussion Results showed that gypsification and calcification are the dominant soil forming processes in the studied region, which have led to the formation of Gypsic and Calcic horizons. This has placed the soils in the Gypsids and Calcids suborders based on the Soil Taxonomy system and the Gypsisols and Calcisols reference soil groups according to WRB system. The representative pedon in the margin of fan and cultivated clay flat (pedon 2) geoform lacks a salic horizon based on the Soil Taxonomy; while it is in the Solonchak reference soil group of the WRB. Also, the presence of argillic horizon in the representative pedon of the margin of fan and uncultivated clay flat geoform (pedon 7) indicates presence of a more humid paleoclimate in the history of the region. The results of clay mineralogy showed that the predominant minerals in the region include chlorite, illite, kaolinite, and smectite. The illite, chlorite, and kaolinite are inherited from papent materials of the soils, and the smectite has a transformation origin (from palygorskite and illite). Addition of this mineral by aeolian or alluvial sediments could not also be neglected. The micromorphological results indicated that the soil pores were mainly chamber. The presence of carbonates and gypsum in the studied soils has caused that the b-fabric in the most horizons to be Calcitic Gypsic Crystallitic. Gypsum was observed in the form of vermicular, lenticular, interlocked gypsum plates and subhedral shapes. Other pedofeatures in the studied soils include calcite nodule and limestone. Conclusion The simultaneous presence of aeolian and alluvial sediments in the different geoforms of Davaran region has caused the formation of stratified soils. Existence of dry climate and lack of significant vegetation in the region from one hand, and the addition of different sedimentary layers at different times (which causes soil rejuvination) on the other hand, has caused that the soils of the region, in general, not to be highly developed. As a result, few differences were observed among soils in different geoforms. Comparing the results of two soil classification systems for the studied soils showed that in general there is a relatively good correlation between them. Totally, the role of climate and parent material in alteration of the studied soils is evident; so that the physical and chemical properties, clay mineralogy and micromorphology of soils in different geoforms have been affected.

Soil spectroscopy has overcome many limitations of conventional soil analysis methods due to its rapid, accurate, cost-effective, and non-destructive nature. This study was aimed to investigate the capability of soil spectral data in estimating some key soil properties and comparing different spectral preprocessing methods in determining the performance of the partial least squares regression (PLSR) model. For this purpose, 100 soil surface samples were collected from the study area which was located between Neyriz and Estahban regions in the east of Fars Province. The samples were analyzed for organic carbon (OC), electrical conductivity (EC), calcium carbonate equivalent (CaCO3) and gypsum using standard laboratory methods. Then, the spectral reflectance of the soil samples was recorded in the range of 350-2500 nm and various spectral pre-processing methods were applied to the data. Afterwards, the soil properties were estimated using PLSR. The results indicated the desirable capability of PLSR method in estimating the amount of gypsum (RPD >2, R2 = 0.81, RMSE = 3.87) and its acceptable ability for OC, EC and CaCO3 (2< RPD < 1.4). Also, the best modeling systems for OC, gypsum and EC were obtained as the first derivative with Savitzky-Golay smoothing method (FD-SG), the standard normal variate method (SNV), and the second derivative with SG smoothing method (SD-SG), respectively. Besides, non-preprocessing data of soil CaCO3 provided better estimations than various pre-processing methods. Overall, the results revealed that the visible spectrum range provided the best performance for estimating of OC and EC, and the NIR range for CaCO3 and gypsum.

Playa, as an important geomorphic position in arid areas, covers about 1% of the continents and has attracted attention of soil scientists and geomorphologists. Soil genetic processes related to landforms and geomorphic processes are of great importance. Micromorphology is among necessary techniques in soil studies which has been used by several researchers. Micromorphological features together with other soil characteristics provide invaluable data for reconstructing soil genetic processes. Moreover, classification and identifying characteristics of soils are pre-requisites for the optimum use and management of soil resources. Soil Taxonomy and World Reference Base (WRB) is among the most extensively used classification systems worldwide. Since no data about soils of the Jazmoorian Playa is available, the present research was performed with the following

1) studying physical, chemical, and micromorphological properties of soils in the Jazmoorian Playa related to different geomorphic surfaces, and 2) classifying soils of the region by Soil Taxonomy (2014) and WRB (2015) systems.

The Jazmoorian playa is located in Kerman and Sistan Baloochestan provinces. The Jazmoorian Playa is a continental depression of late Pliocene. The playa is about 360 m above sea level with about 65 km length and 45 km width located between 58 ˚ to 60 ˚ longitudes and 27 ˚ to 28 ˚ latitudes. The area extends to the igneous Bazman Mountains to the northeast, the igneous Jebalbarez Mountains (granodiorite, andesite, granite) to the north and northwest, the Beshagard Ophiolite Mountains of Cretaceous and Paleocene to the south, and the colored Mélanges to the Oman Sea. Soil moisture and temperature regimes of the area were aridic (and aquic in limited areas) and hyper thermic, respectively. Wet zone, fan delta, clay flat, puffy ground clay flat, sodic clay flat, and salt crust were among the geomorphic surfaces investigated in the playa. In order to study the maximum soil variations in the area, eight representative pedons were described and sampled. Collected soil samples were air dried, grounded, and passed through a 2 mm sieve, and routine physical and chemical soil properties were then analyzed. Undisturbed soil samples were used for micromorphological observations. The soils were classified according to Soil Taxonomy (33) and WRB (11) systems.

Results showed that EC contents of the saturated extracts ranged from 0.5 (fan delta) to 222.2 (salt crust) dS/m. The soils of the playa in Kerman Province affected by the Halilrood River had less salinity compared to the soils on playa surfaces in Sistan Baloochestan Province under influence of the Bampoor River. In addition, salt crust was only formed in parts of the playa located in Sistan Baloochestan Province. Clay coating and lenticular gypsum crystals were among the micromorphological features observed in the Jazmoorian Playa’s soils. The clay coating was formed due to high Na content. However, lenticular gypsum was formed due to small volume pore spaces as well as high salinity of the area. High soluble salts (Table 3) caused a salt coating around pore spaces to be formed due to evaporation of saline water table. WRB system could better classify soils into Solonchak and Solonetz RSGs compared to Soil Taxonomy system which classifies all soils as the Salids sub order. Natric Aquisalids, Typic Natrisalids, Natric Haplosalids, and Puffic Haplosalids sub groups and Natrisalids great group are recommended to be added to Soil Taxonomy system for more harmonization between the two classification systems. Furthermore, the definition of salic horizon in WRB system (EC of at least 15 dS/m and the EC multiplied by thickness of at least 450) is recommended to be included in Soil Taxonomy, because of limitations induced by salts and for a better correlation of the two systems.

Results of physicochemical properties clearly showed that electrical conductivity of soil saturated extracts was in the range of 0.5 to 222.2 dS/m. The part of the playa located in Sistan Baloochestan Province is more saline than the part in Kerman Province. More salinity of playa in Sistan Baloochestan Province was attributed to the Bampoor River which passes through evaporative formations located in east and southeast of the area. Micromorphological observations showed clay coatings and lenticular gypsum crystals as pedogenic features. The soils of the area were classified as Aridisols and Entisols (according to Soil Taxonomy system) and Solonetz, Solonchaks, Fluvisols, and Regosols Reference Soil Groups based on WRB classification system. Moreover, WRB system was capable of separating saline from saline-sodic soils, however, Soil Taxonomy classifies both soils as Salids suborder. Therefore, WRB system is better suited for classification of the soils of our study area as compared with Soil Taxonomy.

Soil classification is a process of showing basic differences among soil classes (5). Different soil classification systems are created for soil classification, but Soil Taxonomy and World Reference Base for Soil Resources (WRB) are among the most favoured systems in the world including Iran. This system (WRB) is accepted by soil scientists in the world and Soil Taxonomy has also been used in several countries (7). Each of the two mentioned systems has its own strong and/or weak points to show soil characteristics. However, comparing Soil Taxonomy and WRB for calcareous and gypsiferous soils of central Iran, Sarmast et al. (16) reported that according to specifiers used in WRB, this system could be more efficient than Soil Taxonomy. Various environmental conditions and its fluctuations in Kerman Province caused different soils to be formed in the province. Use of soil moisture and temperature regimes by Soil Taxonomy which is totally neglected by WRB system may emphasize that Soil Taxonomy could provide better results for these soils. That is why the present research was performed to compare Soil Taxonomy and WRB systems in the area of the present research with different climates and to show the efficiency of the two systems to describe selected soil characteristics in Kerman Province.

According to climatic variations, four study sites were selected in Kerman Province. Sites 1 (elevation of < 2000 m asl) and 2 (elevation of >2000 m asl) in Baft and Rabor areas were located in the south west of the province. Moreover, sites 3 (around Jiroft and Anbarabad) and 4 (around Roodbar-e-Jonoob and Ghaleganj) were located at the center and south of the province, respectively (Fig. 1). Table 1 shows the soil moisture and temperature regimes of the areas under study (3). Twenty-five pedons on different geomorphic surfaces were described and one representative pedon on each geomorphic surface (total of 11 representative pedons) were selected (Fig 1). Soil description and sampling performed (18) and the collected samples transferred to the laboratory. It is to be noticed that soil moisture regime in site 3 has changed from ustic to aridic during normal years defined in Soil Taxonomy. Ustic/ hypertermic soil moisture/temperature regimes were reported for soils of Jiroft and Anbarabad according to the soil moisture and temperature map of soils of Iran (3). However, according to the latest climatic data (30 years' data and the concept of normal years as defind in Soil Taxonomy, 2014) used in the NSM Software, the soil moisture regime was estimated as weak aridic.

Histic, mollic, argillic, natric, calcic, anhydritic, and cambic horizons were investigated after field work and laboratory analyses. Results of the study show that addition of new Calcixeralfs, Gypsiustalfs, and Gypsicalcids great groups together with newly added Calcic Natrargids, Calcic Natrustalfs, Gypsic Calciustalfs, Typic Petrogypsids, Anhydritic Haplogypsids, and Angydritic Petrogypsids subgroups to the Soil Taxonomy system from one hand, and addition of anhydrite and hypercalcic qualifiers to WRB from the other hand, cause a higher correlation between the two systems. Besides, climatic fluctuations of the recent years in Jiroft and Anbarabad areas caused a change in the soil moisture regime according to normal years defined in Soil Taxonomy. That is why soil name was changed in Soil Taxonomy system. However, WRB system shows no variation because this system is not related to climatic data. Since anhydritic horizon was added to Soil Taxonomy (2014) system, addition of this horizon is recommended to WRB for better correlation of the two systems as was also suggested by Sarmast et al. (16). Meanwhile, soil names in the WRB system provide more information about characteristics of young soil (including yermic qualifier to show desert pavement) compared to Soil Taxonomy.

Conclusion:

 Soil classifications showed that WRB system could describe soil characteristics in the area more efficiently compared to Soil Taxonomy. Climate change caused a variation in soil moisture regime of Jiroft and Anbarabad areas according to normal years of Soil Taxonomy system, which in turn changed soil nomenclature in this system. WRB system is not related to climate that is why soil names were not changed in the above mentioned areas. Besides, WRB system is more efficient to classify gypsiferous soils because gypsum content which is an important factor for management of gypsiferous soils is better focused by WRB. However, lack of anhydritic horizon in the WRB system is a weak point, that is why addition of this horizon was suggested by the authors. It is recommended that soil moisture/temperature regimes of study sites be calculated by softwares using climatic data because the climatic variations of the recent years might have changed the soil moisture/temperature regimes reported in the map of 1998 due to the definition of normal years defind in Soil Taxonomy.

Introduction:

 Increasing demand for an international classification system as a unique communication tool in soil science has caused development of different systems.  Like many other countries, Soil Taxonomy and WRB are the most popular soil classification systems in Iran. Genetic and morphologic soil properties are used for soil classification in both systems. However, correlation of the two systems and efforts to harmonize them have been a major concern among soil scientists. Comparing Soil Taxonomy and WRB in gypsiferous and calcareous soils of central Iran, Sarmast et al. (13) reported that WRB using various qualifiers is more effective than Soil Taxonomy. Since no study on soils of Iranshahr and Dalghan Regions located in Sistan and Baloochestan Province has performed and/or no reported data is available, the present research was performed to: 1) study morphological, physical, and chemical soil properties in the area, 2) classify soils based on Soil Taxonomy (2014) and WRB (2015) systems, 3) compare the two systems for soil description in Iranshahr and Dalghan regions as a part of Sistan and Baloochestan Province, central Iran.

The study area starts from Iranshahr (590 m asl) in the center of the province and extends to Dalghan (390 m asl) in west. Alluvial fan, pediment, playa, and hill were among different landforms identified using field studies, topography maps (1:50000), and Google Earth image observations. To cover the maximum soil variations in the area, 10 representative pedons were selected, described, and sampled.

Calcic, gypsic, anhydritic, argillic, natric, and salic horizons identified after field work and laboratory analysis. Results of the study showed that addition of Yermic Torrifluvent, Yermic Torriorthent, Calcic Gypsiargid, Gypsic Natrsalid, Natric Gypsisalid, Anhydritic Gypsisalid, Anhydritic Calcisalid subgroups to Soil Taxonomy system from one hand, and addition of anhydrite and aquic (for Solonchak reference soil group) qualifiers to WRB system from the other hand, causes a higher correlation and more harmonization between the two classification systems. Meanwhile, the minimum percentage of calcium carbonate equivalent necessary for calcic horizon identification in coarse textured soils including gravel in Soil Taxonomy is also suggested to be added to WRB system. Besides, requirements of salic horizon in WRB system is recommended to be added to Soil Taxonomy. At the same time, soil names in WRB system provide more information and data about soil properties and characteristics in young soils (such as yermic qualifier showing desert pavement) compared to Soil Taxonomy. Soil Taxonomy is not able to properly classify saline soils of arid regions down to subgroup level which is a weak point for this system. That is why newly added Gypsic Natrsalids is suggested for soils with natric, gypsic, and salic horizons in the upper 100 cm of the soil. On the other hand, the requirements of salic horizon in WRB system (the minimum EC content of 15 dS/m and the EC multiplied by the horizon thickness of more and/or equal to 450) are also suggested for Soil Taxonomy.

Results of the study for both saline and sodic soils show more capability of WRB system compared to Soil Taxonomy to classify soils. From soil management point of view, natric horizon causes more negative effects compared to salic horizon because Na disperses the soil particles and destroys soil structure and sodic soils need more practices to be improved compared to saline soils. Results for gypsiferous soils also show more capability of WRB system compared to Soil Taxonomy because gypsum content which is important for gypsiferous soils management is properly concerned in WRB system. However, lack of anhydritic horizon in WRB seems to be a weak point for this classification system. That is why it is suggested to be added to WRB (13). Since Soil Taxonomy does not use independent abbreviations for anhydritic horizon compared to gypsic horizon, the Ba and Baa abbreviations are also suggested for Soil Taxonomy to be added.

Several archaeologists believe that there is a relationship between cultural residuals, human beings, and soil. Soil related factors such as age index, climate change, and paleoclimate are important in archaeology. Soils could be accounted as records of invaluable information. Appropriate compiling of these data cause better understanding of soil and landscape genesis, and human activities in the past. There are two distinguished archeological sites of Daqyanous (Islamic Era) and Konarsandal (before Islamic Era) in Jiroft area. Besides, Konarsandal site is surrounded by old and new Halilrood channels. Since no data about the comparison of soil evolution in the mentioned archeological sites were available, the present research was conducted to compare soil evolution of archaeological sites using soil classification, clay mineralogy, and micromorphology in Jiroft area.

soil samples were collected from three different archaeological sites including new channel of Halilrood (pedon 1), old channel of Halilrood (pedon 2) and, Daqyanous (pedon 3). The samples were air-dried and sieved (2 mm). Routine soil physical and chemical analyses including pH, EC, soil textural class, soluble sodium, calcium, and magnesium, and gypsum and calcite contents were performed. The studied pedons were classified using Soil Taxonomy system according to morphology, laboratorial results, and field observations. The clay minerals were determined by X-ray diffraction (XRD) method after carbonates, organic matter, and Fe were removed using Jakson (1965) and Kittrik and Hope (1963) procedures. Ten undisturbed samples were selected for micromorphology studies and thin section preparation.

Pedon 1 is affected by Halilrood River sediments, that is why an old soil together with a young soil was formed. Salinity and SAR in the old soil were higher than the upper young soil. A textural discontinuity was found between the old and the young soils. Natric, calcic, and gypsic horizons were found in pedon 1 and caused a Typic Natrargid to be formed in new Halilrood channel. Natric horizon due to high Na cation was formed in pedons 1 and 2. On the other hand, salic, natric, and cambic horizons formed a Typic Haplosalid in pedon 2 (old Halilrood channel). High salinity and SAR in the upper layers caused salic and natric horizons to be formed. Pedon 3 with argillic horizon is an old polygenetic soil. Available humidity in the past caused removal of carbonates from upper layers that followed by clay illuviation and argillic horizon formation. Salinity and SAR in this soil were low and a heavy texture was found in pedon 3. Since pedon 3 showed cambic, argillic, and calcic horizons, it was classified as Arenic Haplargids. Calcium carbonate, gypsum, Fe oxides, and clay coatings were among dominant micromorphological features observed in the studied pedons. Konarsandal archeological site is located in the lowlands of Jiroft plain downward Rabor and Baft elevations. Lenticular gypsum crystals could be attributed to the solution of upward Neogene formations and groundwater close to the surface which evaporates due to capillary. Powdery calcite, Fe-oxides, and clay coating and infilling of gypsum in pore spaces of pedon 1 were observed by micromorphological investigations. Diffused clay coating around pore spaces is explainable by high sodium content and Natric horizon formation. Lenticular, interlocked plates, and infillings of gypsum were observed in pedon 1. However, gypsum with irregular shapes and low content was investigated in pedon 2. This is due to location of this pedon in Halilrood old channel. That is why pedon 2 affected by Halilrood during long periods of time is unstable and shows less evolution compared to pedon 1. Irregular and lenticular forms of gypsum show weak soil development due to low rainfall, high evaporation, and excess salt. High NaCl is reported as a requirement for lenticular gypsum formation. This form of gypsum is supported by high salinity in pedons 1 and 2. High Na and natric horizon formation in pedons 1 and 2 caused dispersion of clay and ceased formation of clay films around pore spaces. Gypsum was not found in pedon 3 during filed and laboratory studies. Besides, gypsum was not observed by micromorphological observations. Clay and calcite coatings and calcite infillings were among the micromorphological features observed in pedon 3. Calcite coating on clay coating in this pedon could be attributed to the climate with more available humidity in the past followed by an arid climate. Carophyte algae fossil was only observed in pedon 3. Kaolinite, illite, chlorite, smectite, and palygorskite clay minerals were determined by X-ray diffraction. Palygorskite is highly related to the parent material and climate. Pedogenic palygorskite formation from transformation of 2:1 clay minerals and/or neoformation is reported by several studies. Due to the impact of paleoclimate with more available humidity, palygorskite was not found in Daqyanous archeological site. It seems that higher humidity in the past did not allow palygorskite formation or transformed it into smectite. Chlorite and illite are originated from parent material. Evidences of pedogenic mica minerals in arid and semi-arid environments were also found which is due to K fixation among smectite layers. Smectite with pedogenic origin is also reported by Sanjari et al. (29) in the study area. Chlorite, illite, and kaolinite clay minerals seem to be originated from parent material in the present study.

Laboratories analyses and micromorphology observations clearly showed weak development in Konarsandal pedons compared to high evolution of soils in Daqyanous archaeological site. The same results were also found for unstable surfaces of pedons 1 and 2 compared to stable surface of pedon 3. The stable surface provided the accumulation of clay and calcite coatings around the cavities and the formation of argillic and calcic horizons indicating high soil development. Results of the study showed polygenetic formation in soils. Soils in old Halilrood channel show high salinity and Na adsorption ratio compared to other two pedons under study.

Soil maps are a common source of information for land suitability studies. Land suitability studies are to compare land characteristics with the needs of land-use types and to select the best land-use productivity types for cultivation. Land evaluation analysis is considered as an interface between land resources and land use planning and management. However, the conventional soil surveys are usually not useful for providing quantitative information about the spatial distribution of soil properties that are used in many environmental studies. Development of the computers and technology lead to develop the digital and quantitative approaches in soil studies. These new techniques rely on the relationships between soil and the environmental variables that explain the soil forming factors or processes and finally predict soil patterns on the landscape. Different types of the machine learning approaches have been applied for digital soil mapping of soil classes. To our knowledge, most of the previous studies applied land suitability evaluation based on the conventional approach. Therefore, the main objective of this study was to assess the performance of digital mapping approaches for the qualitative land suitability evaluation in the Jiroft plain of Kerman province.

An area in the Jiroft plain of Kerman Province, Iran, across 28º14′ and 28º 26′N, and 57º 30′ and 57º 46′E was chosen. The study area is placed on alluvial plain, gravelly alluvial fans, eroded hills. Based on Google Earth image, geomorphology and topography maps and also field survey, 62 pedons were selected and excavated, and soil samples were taken from different soil horizons. Then, soil physicochemical properties were determined. To assess the climate, the climate information obtained from the Jiroft Synoptic Station. The average of soil properties was determined by considering the depth weighted coefficient up to 100 centimeters for potato. Qualitative land suitability evaluation for potato was determined by matching the site conditions (climatic, hydrology, vegetation and soil properties) with studied crop requirement tables presented by Givi (5). Land suitability classes were determined using parametric method. Land suitability classes reflect degree of suitability as S1 (suitable), S2 (moderately suitable), S3 (marginally suitable) and N (unsuitable). For digital approach, multinomial logistic regression (MLR) was used to test the predictive power for mapping the land suitability evaluation. Terrain attributes (elevation, slope, aspect, wetness index and multiresolution valley bottom flatness (MrVBF)), remote sensing indices (normalized difference vegetation index (NDVI), perpendicular vegetation index (PVI), and ratio vegetation index (RVI)), geology map, and geomorphology map were used as auxiliary information. Finally, all of the environmental covariates were projected onto the same reference system (WGS 84 UTM 40 N). Training and validating the model was done by leave-one-out cross validation. The accuracy of the predicted soil classes was determined using error matrices and overall accuracy.

The results showed that climatic conditions are suitable (S1) for potato. The most important limiting factors were the gravel content, soil acidity and soil salinity for potato growing in the study area. Land suitability classes S2 to N were determined based on land index in the study area. The modelling results demonstrated overall accuracy 0.47 and 0.25 for class and subclass of land suitability, respectively. It seems that low number of soil samples for training and validating of the model were probably caused to low accuracy as compared to the other researches. In addition, the overall accuracy decreased from class to subclass. The terrain attributes (slope and aspect), remote sensing indices (normalized difference vegetation index) and geomorphology map were the most important auxiliary information to predict the land suitability classes and subclasses. This indicates the importance of geomorphological processes for determining the land suitability class in the study area.

Results suggest that the land form, land position and geomorphology processes affect soil properties and then, land suitability classes. Therefore, variability of land suitability classes is function of variability of soil properties. Digital approaches could help to obtain the information with high resolution, provided that the criteria of suitability are associated with variability of soil properties. Although digital mapping approaches increase our knowledge about the variation of soil properties, integrating the management of the sparse lands with different owners should be considered as the first step for optimum soil and land use management.

Increase of water holding capacity induced by polymers has been developed in arid and semi-arid regions. The effect of polymers on increasing water holding capacity and the effect of selected polymers on some growth characteristics of corn plant under drought stress was carried out in both experimental and greenhouse condition, respectively.

The present research included two complementary parts performed in laboratory and greenhouse. First, the effect of 11 polymer treatments (polymer type and concentration) including Karacoat 1and 3 %, Acrylic 1 and 3 %, Polyvinyl acetate 1 and 3 %, Superab 0.5 and 1 %, Stockosorb 0.5 and 1 % and control without polymer on moisture changes of two soils (loamy sand and sand) during 11 times (0, 12 h, 1, 2, 4, 6, 8, 10, 12, 16, 20 day) were studied in laboratory and 4 best polymer treatments were selected for greenhouse cultivation. In greenhouse, the effect of polymer treatments (Karacoat 1and 3 %, Stockosorb 0.5 and 1 % and control without polymer) under drought stress (30, 50 and 80 % field capacity) on some growth characteristics of corn plant (leaf number, height, wet and dry weight of stem and wet and dry weight of root) were studied separately in loamy sand and sandy soils.

Results showed that increase of moisture in both treated soils was higher than control and from this point of view, water soluble polymer-Karacoat 3 % (18.5 % compared to loamy sand control and 35.9 % compared to sandy control) and Stockosorb 1 % hydrogel (95.8 % compared to loamy sand control and 3.4 times compared to sandy control) were more powerful. Mean moisture after 20 days for water soluble polymers and Superab hydrogel was higher in loamy sand than sandy soil. But, Stockosorb 1 % hydrogel was more effective in sandy soil (16.1 % increase compared to loamy sand soil). With increasing polymer concentration, the moisture content of polymer treated soil samples increased. To increasing water holding capacity Stockosorb 1% hydrogel in loamy sand (0-12 day) and sandy (0-16 day) soils was more successful than other polymer treatments. Both water holding capacity during the time and final moisture content in sandy soil treated with polymers were more than loamy sand soil. Leaf number, stem height, wet and dry weight of stem and dry weight of root in corn plant were reduced under drought stress. In contrast, height, wet and dry weight of corn stem were better in stockosorb hydrogel 1 % treatment. Wet weight of corn stem in loamy sand soil under drought stress was significantly affected (P < 0.01) by stockosorb hydrogel. Stockosorb 1% hydrogel increased wet weight of stem 59.29, 82.41 percent and 3.82 time in low, medium and severe stress compared to control, respectively.

According to the results karacoat 3 % and stockosorb 1 % are recommended for increasing moisture and water holding capacity of coarse texture soils. Moreover, polymer materials with properties such as useful longevity, high efficiency at low concentrations, and local application in the root zone of trees could provide ideal condition for plant which growth in soils with low water holding capacity. In addition, they are ideal for drought condition that is common in arid and semi-arid regions where rain is low and evaporation is high.

Wind erosion is one of the most important land degradation aspects especially in arid and semi-arid regions such as Kerman province. Wind direction and speed are two important erosive factors affecting wind erosion and sediment yield. The purpose of this study was to analyze the erosive winds of the province in order to determine the direction of predominant winds and the status and the potential of wind erosion during different periods of 8 to 11 years.

In this study, wind anemometric data for 8-11 y periods were analyzed using 12 synoptic stations in Kerman province. For this purpose, the WR Plot View software was applied in order to analyze the anemometer data and draw wind roses and storm roses of the selected synoptic stations of the province. Moreover, the sand roses of the studied stations were plotted using the Sand Rose Graph 3 software, accordingly different sand drift potential and direction indices were derived.

The results of wind rose analysis generally indicated that the western and southwestern winds dominated in the western part of the province, whereas the northern winds were more frequent in the eastern part. Storm rose analysis showed that in most stations, the highest erosive winds were mainly blown from the west and south west directions, while at Bam and Shahdad stations the north and at Zarand the southwest and northeast winds were predominate. According to this analysis, the most frequent winds at the speed classes of ≤6.7, 6.7-7.7, and 7.7-9.8 m s-1 were allocated to Jiroft (94.9%), Sirjan (8.0%) and Kahnooj (12.0%) stations, respectively. Among all the stations, Rafsanjan with 10.9%, 5.0%, and 4.1% showed the most frequent winds at the higher speed classes of 9.8-11.8, 11.8-13.9, and ≥13.9 m s-1, respectively. The analysis of resultant drift direction (RDD) implied that sand transport for the western stations of the province was mainly toward east and northeast directions, for Zarand station was from northwest to southeast and for Shahdad and Bam stations was from north to south directions. The minimum amount of total drift potential (DPt) was found at Baft and Jirof stations by 398 and 400 v.u., respectively, while Rafsanjan station with 1665 v.u. experienced the highest value of this index. Except for Baft and Jiroft stations with moderate wind potential, the other stations showed high wind potentials. The analysis of uni-directional index (UDI) indicated that except for Jiroft and Zarand stations which had high variability with multi-directional winds, for the other stations moderate variation with bi-directional winds and oblique angle were observed.

It was concluded that although wind erosivity analysis gives valuable information on wind erosion situation and sediment transport, it is necessary to be considered and used the threshold velocity as well as soil erodibility databases in order to achieve a more accurate analysis of wind erosion in the province.

Introduction: Under natural conditions, intensive and erosive storms commonly associate with high-speed winds. In fact, wind velocity affects water erosion rate through enforcing falling drops and enhancing rainfall erosivity. Therefore, knowledge of interaction between wind and rain as erosive agents on interrill erosion is of prime importance. However, no comprehensive study has been done on this topic under controlled laboratory conditions. This study was conducted to investigate interrill erosion affected by different rain intensities and wind velocities on several soils with different aggregate size distributions using the Simultaneous Wind-Rainfall-Runoff Simulator (SWRRS). For this purpose, a multisystem was constructed for the first time in Iran to investigate the simultaneous effects of wind and rain erosivity agents on soil erosion under laboratory conditions. Materials and Methods: The simulator was calibrated in two cases. First, the intensity and uniformity of the simulated rains were assessed for each nozzle, separately. Second, the calibration procedure was performed for different combinations of the selected nozzles to achieve the best performance. For each case, different water pressures were generated to introduce several water discharges and make initial raindrop velocities. Afterwards, the interrill erosion experiment was done using four constant wind speeds including 0, 6, 9 and 12 m s-1at the height of 40 cm which were applied in combination with three rain intensities of 30, 50 and 75 mm h-1 on three soil samples with different aggregate size distributions (D2mm, D4.75mm and D8mm). Each treatment was conducted at three replicates under laboratory controlled conditions. By using different wind speeds, rain intensities and soil aggregate sizes, interrill erosion rate was measured under steady state conditions. Results and Discussion: Results showed that wind velocity has a significant effect on interrill erosion rate and the interaction between wind and rain on interrill erosion was significant, as well. Although, there was no significant difference between the erosion rate at wind velocity of 0 and 6 m s-1, the wind velocity of 9 and 12 m s-1 showed significant difference with and higher erosion rates than the velocity of 6 m s-1. The mean erosion rate at wind velocities of 0, 6, 9, 12 m s-1 was 0.43 × 10-4, 0.54 × 10-4, 0.97 × 10-4 and 1.46 × 10-4 kg m-2 s-1, respectively. With increasing rain intensity from 30 to 75 mm h-1, the erosion rate increased from 0.52 × 10-4 to 1.16 × 10-4 kg m-2 s-1. On average, the erosion rate of the soil containing larges aggregates i.e. D8mm (0.73 × 10-4 kg m-2 s-1) was less than that with the finest aggregates i.e. D2mm (0.99 × 10-4 kg m-2 s-1). The findings of this study highlighted the importance and necessity of more attention to wind speed particularly those velocities faster than a threshold velocity in the study of interrill erosion. Conclusion: In arid and semi-arid regions such as most parts of Iran, rainstorms are usually accompanied by strong winds. Despite the undeniable influence of wind on the erosive power of rain, a host of research has investigated water and wind erosion processes, separately. Therefore, this study was done to investigate the simultaneous effect of wind velocity and rain intensity on interrill erosion rate in three soil samples. The results indicated that wind velocity has a remarkable influence on interrill erosion rate due to wind-driven rain. Wind velocities faster than 6 m s-1 increased interrill soil erosion rate, particularly those combined with higher rain intensities. This is due to an increase in the velocity of falling raindrops on the soil surface which results in greater kinetic energy. Also, the findings showed that the soil containing coarser aggregates due to greater random roughness exhibited less sensitivity and interrill erosion rates as compared with the soil having finer aggregates, especially at faster wind velocities. The rate of interrill erosion in soil D2mm was 1.35 times higher than soil D8mm indicating the importance of random roughness. In addition, there was no significant difference between the measured erosion rates at wind speeds of 0 and 6 m s-1, in all cases. However, with increasing wind speed from 6 to 9 and also to 12 m s-1, significant increases in soil erosion rates were observed. Accordingly, a threshold wind velocity can be considered in wind-driven interrill erosion. The findings of the present study can be applied for better understanding and modeling of water and wind erosion mechanisms and dominant processes.

Soil magnetic properties reflect the complex chemical, geological and biological interactions occur in the soil. Thus, knowledge about the factors affecting soil magnetic properties helps better understanding and interpreting the results.. The lithogenic magnetic minerals are often found in the coarse soil fractions (sand and silt) and they have inherited from parent rocks. Weathering and soil formation factors may lead increasing or decreasing of magnetic susceptibility. Climate and vegetation type are among the other factors affecting magnetic susceptibility too. Amount and distribution of magnetic susceptibility may also be affected by land use. The main objective of this research was to study the effect of different land uses and vegetation types on the magnetic susceptibility of topsoil related to soil properties.
The study area was located in MahoonakeZiba around the Bardsir region, Kerman Province. The moisture and temperature regimes of the study area were sub aridic and mesic, respectively. The study area is located in the alluvial plain with igneous parent material originated from andesite, volcanic tuff, anddacite. Four land uses including farmland, well-covered pasture, disturbed pasture and degraded dryland farm with similar climate, topography, and parent material were selected. Overall, 60 complex surface samples were collected from the depth of 0-15 cm. The physicochemical analyses were done on the samples after that the soils were air dried, crushed, and passed through a 2 mm sieve. The soils magnetic susceptibility (ᵡ) in low (0.46 kHz) and high (4.6 kHz) frequencies were measured using the Bartington MS2 dual frequency sensor in two replications. The frequency depended magnetic susceptibility (ᵡfd %) was calculated as a development index of soil forming factors reflecting ferrimagnetic particle sizes.
The pH of studied soils were in the range of neutral to alkaline and had the lowest coefficient of variance between measured parameters. The average of soil EC was 1.76 dS/m with a high coefficient of variance. The lowest amount of organic matter was in land use ofdegraded drylandfarm (0.26 %) and the highest was in farmland (2.15 %). The lowest amount of calcium carbonate with the coefficient of variance 12.37 % measured in the degraded pasture and its maximum was in the farmland. The loamy sand and sandy loam textural classes were found in the area under study. The minimum and maximum amounts ofᵡlf were determined in farmland (134.8× 10-8 m3 kg-1)and well-coveredpasture (1778.9 ×10-8 m3 kg-1 ), respectively and the relatively high mean value was 695.83 × 10-8 m3 kg-1. The topsoil of the study area was formed on alluvial deposits with a parent material originated from igneous andesite, tuff and dacite rocks. The high values of magnetic susceptibility of all soils under study could be attributed to the existence of initial magnetic minerals inherited from the parent material. The statistical analysis revealed a significant difference among ᵡlf values (p

Genesis and development of soils are highly affected by soil forming factors and processes. Climate and topography (landform) are among the factors affecting weathering of parent material and genesis and development of soils in an area. Besides, various morphological, physical, and chemical properties, micromorphology, and clay mineralogy of soils at different geomorphic positions are usually affected by different soil forming factors including parent material and climate. The objectives of the present research were to study the effect of climate and geomorphology on physicochemical properties, micromorphology, and clay mineralogy of the soils in Rayen area, Kerman Province.
The study area starts from Hezar mountain elevations close to Rayen city (south east of Kerman Province) and extends to plateaus surfaces around Bam city. Quaternary and Neogene formations were found from geology point of view. Mean annual precipitation is in the range of 200-300 mm. Five landforms including rock pediment, mantled pediment, piedmont plain, plateaus, and valley were investigated during field work followed by topography, geology, and Google map studies in the area. According to 1:2500000 map provided by Soil and Water Research Institute, xeric and aridic soil moisture regimes together with mesic soil temperature regime were found in the area. Nine representative pedons were studied based on climatic regimes and different geomorphic surfaces. Pedons 1 and 2 were located on rock pediment with an aridic soil moisture regime. On the other hand, pedon 3 was located on the same surface, but with xeric moisture regime. Pedons 4 and 5 were also located on mantled pediment with aridic and xeric moisture regimes, respectively. Pedon 6 was located on piedmont plain and in the aridic moisture zone. Pedons 7, 8 (Plateaus), and 9 (Valley) were all in the aridic moisture zone. Physical and chemical properties, micromorphology, and clay mineralogy of soils were investigated and the soils were classified using USDA Soil Taxonomy (12th edition) and latest edition of World Reference Base for Soil Resources (WRB) systems.
Cambic, gypsic, argillic (or argic), calcic, and petrocalcic horizons were investigated during field and laboratory studies. Typic Haplocambids (pedons 1 and 2), Typic Calcixerepts (pedon 3), Typic Torriorthents (pedon 8), Calcic Petrocalcids (pedon 7), Typic Calcigypsids (pedon 6), Typic Xerorthents (pedon 5), Typic Haplocalcids (pedon 4), and Typic Calciargids (pedon 9) were classified using Soil Taxonomy (2014) and Gypsisols (pedon 6), Calcisols (pedons 3, 4, 7, and 9), Cambisols (pedons 1 and 2), and Regosols (pedons 5 and 8) Reference Soil Groups were determined using WRB (2015) system. Electrical conductivity increased from rock pediment toward valley and decreased from aridic toward xeric soil moisture regimes. Formation of argillic horizon in pedon 5 (Xeric moisture regime) was attributed to the climate of present time, but pedons 8 and 9 with aridic moisture regime could probably have experienced a climate with more available humidity for argillic horizon to be formed. Besides, petrocalcic horizon formation in pedon 7 was also attributed to a climate with more available humidity in the past. A buried soil (Btkb horizon) was determined in pedons 5 and 8 under the modern soil. Soil moisture regime change from aridic to xeric in rock pediment surface caused change of Aridisol to Inceptisol, but classification of soils in WRB system, was not affected. Secondary forms of calcium carbonate including powdery pocket, soft masses, and mycelium and secondary gypsum such as fine and coarse pendants were found during field studies. Calcite, gypsum, and clay coatings and infillings together with isolated gypsum crystals and gypsum interlocked plates were among dominant micromorphological pedofeatures investigated. Calcite coatings on aggregates and soil particles associated with clay coating prove the role of paleoclimate in soil formation. On the other hand, presence of manganaze nodules is an evidence of oxidation/reduction condition taken place in the xeric moisture conditions of pedon 5 (rock pediment). Illite, chlorite, kaolinite, and smectite were investigated in both rock and mantled pediments, but palygorskite was only found in mantled pediments. Climate also played a significant role in determining the source (pedogenic or geogenic) of clay minerals.
Results of this study clearly showed the close relationship among soil formation, topography (geomorphic surface) and climate. Soil physicochemical properties, micromorphology, clay mineralogy, and soil classification were highly affected by climate and geomorphology.

The optimum and sustainable use of soil is only possible with correct and complete understanding of its properties. The objectives of the present research were to study 1) genesis and development of soils related to different geomorphic surfaces in Kouh Birk Area (Mehrestan City), 2) Soil classification according to Soil Taxonomy (2014) and WRB (2014) systems, and 3) physicochemical properties, clay mineralogy and micromorphology of soils.
Mean annual rainfall and soil temperature in the selected location are 153.46 mm and 19.6 oC, respectively. From geological point of view, the studied area is a part of west and south west zones and Flysch zone of east Iran. Soil temperature and moisture regimes of this part are thermic and aridic, respectively. Eight representative pedons on different surfaces including rock pediment, mantled pediment, Alluvial fan and Upper terraces were selected, sampled, and described. Routine physicochemical analyses, clay mineralogy, and micromorphological observations performed on soil samples. Soil reaction, texture, electrical conductivity, calcium carbonate, and gypsum were identified. Four samples including Bt horizon of pedon 1, Bk1 horizon of pedon 4, By2 horizon of pedon 5 and Bk1 horizon of pedon 7 were selected for clay mineralogy investigations. Four slides including Mg saturated, Mg saturated treated with ethylene glycol, K saturated, and K saturated heated up to 550 oC were analyzed. A Brucker X-Ray diffractometer at 40 kV and 30 mA was used for XRD analyses. Undisturbed soil samples from Bt horizon of pedon 1, Bk2 horizon of pedon 2, Btn horizon of pedon 3, By2 horizon of pedon 5, Bk1 horizon of pedon 7, and By1 horizon of pedon 8 were selected for micromorphological observations. A vestapol resin with stearic acid and cobalt as hardener was used for soil impregnation. Bk-Pol petrographic microscope was used for micromorphology investigations.
Due to the presence of argillic and petrocalcic horizons in rock pediment, soils of this surface were more developed compared to other landforms. High amount of CaCO3 (39.5%) was observed in pedon 4 on rock pediment geomorphic surface which is attributed to calcareous parent material. The presence of argillic horizon in this geomorphic position is due to the more available water of the past climate. The maximum salinity was observed in the mantled pediments. Calcic over gypsic horizons formed in pedon 7 on alluvial fan surface due to higher solubility of gypsum than calcium carbonate. Kaolinite, illite, chlorite, and palygorskite clay minerals were found in pedons 1 and 4 on rock pediment. Palygorskite in this position seems to be pedogenic, but kaolinite, illite, and chlorite are inherited from parent material. Mantled pediment and alluvial fan showed smectite, kaolinite, illite, chlorite, and palygorskite clay minerals. Pedogenic smectite in this position is probably formed from weathering of illite and chlorite. On the other hand, palygorskite stability decreased in mantled pediment surface. This is the reason why smectite was the dominant clay mineral in this landform. Clay and calcite coatings were investigated in Bt horizon of pedon 1 (rock pediment). Coatings and infillings of calcite in Bk2 horizon of the same geomorphic position caused a calcic crystallitic b fabric. A diffused clay coating due to the presence of Na in Btn horizon of pedon 3 in rock pediment was observed. Micromorphological observations of By2 horizon in pedon 5 (mantled pediment) showed gypsum interlocked plates and gypsum infillings. Interlocked plates formed due to re-solubility of gypsum crystals. Micro spars and infillings of calcite are among dominant pedofeatures found in Bk1 horizon of pedon 7 (alluvial fan geomorphic surface). A calcic crystallitic b fabric and Primary calcite mineral were also observed in this pedon. Release of Ca from calcareous parent material caused Ca to SO4-2 ratio to be increased which could be a probable source of gypsum formation. Results of the study showed that more and less developed soils formed on rock pediment and upper terrace geomorphic surfaces, respectively. Illuviation of clay, gypsum, and CaCO3 together with formation of cambic, calcic, petrocalcic, gypsic, argillic, and natric horizons were among the dominant pedogenic processes in studied soils. Paleosols containing Bt horizons were only observed on rock pediment geomorphic surface. Kaolinite, illite, chlorite, and palygorskite clay minerals were observed in almost all surfaces. Smectite was not discovered in rock pediment, but was only investigated in mantled pediment and alluvial fan which could be attributed to higher available moisture of formation time in these surfaces. Secondary calcite and gypsum caused stability of pedogenic palygorskite in soils under study. Micromorphological observations proved the presence of clay and calcite coatings, calcite and gypsum infillings, and gypsum interlocked plates. Gypsum pedofeatures were not observed in rock pediment, but clay and calcite pedofeatures were only found. On the other hand, clay and calcite pedofeatures were not observed in upper terraces and gypsum pedofeatures were the only features determinded in this position.
Results of the present research showed that difference in soil characteristics is highly affected by geomorphology.

Study of land use effects on soil quality indicators leads to sustainable management and preventing progressive land degradation. The TM (1987) and ETM+ (2000 and 2005) data were used to study land use change effects in Mahan-Joopar area on soil quality indicators. Fifty random soil samples from 0-30 cm depth of each land use were taken using provided maps. Organic matter, microbial respiration potential, bulk density, pH, EC, and soil texture were investigated as soil quality indicators. Eight land uses including fruit orchards, woodlands, pistachio orchards, cultivated, barren, bare land, fallowed, and haloxylone land were detected. Results showed overall accuracies of 89.4, 95.2, and 91.7 % with kappa coefficients of 85, 92, and 88% for maps provided in 1987, 2000, and 2005, respectively. Generally, the investigated quality indicators showed that woodlands, fruit orchards, cultivated land, and pistachio orchards enhanced soil quality better than other land uses.