Physiographic Units Research Articles

Geomorphic signatures of neotectonic activity along the Western Andean Front in the Chilean Andes (35°S to 37°S)

AbstractCharacterizing neotectonic activity along mountain fronts in active orogens is the key to better understanding trajectories of landscape evolution, climatic‐tectonic couplings and natural hazards. One such prominent mountain front is the Western Andean Front (WAF), which defines the boundary between two main physiographic units along the Chilean Andes (15°S to 39°S): the Central Depression and Principal Cordillera. This study analyses the geomorphic imprints of neotectonic fault activity in the WAF between 35°S and 37°S. We used several topographic metrics, including the mountain‐front sinuosity index (Smf), the valley floor width‐to‐height ratio (Vf) and the stream length‐gradient (SL) index to gain information about the regional distribution of deformation patterns and its relative tectonic activity for distinctive segments. In addition, a raster map combining rock strength (RS) and mean annual precipitation (MAP) allowed discriminating lithology‐climate vs. tectonics influence on SL anomalies from catchments spanning from the main deformation zone to the regional drainage divide. We use the local relief and swath profiles to quantify the incision and transient state of mountain fronts to evaluate the geomorphic response to tectonic and/or climatic input. Our analysis highlights significant variations from north to south, delineating two distinct segments with different topographic, geomorphic and geometric fault characteristics. These segments are indented at approximately 36°S. From north to south, there is a segment with an inactive thrust front with a primarily climate‐driven fluvial response over long timescales and a second segment with a transient state adjusting to relatively high uplift rates. Morphometric data analysis, DEM‐based morpho‐structural maps, geological maps and previous research support the interpretation of two sets of neotectonic faults: (1) NNE‐striking reverse faults with a dextral slip component and (2) NW‐striking sinistral slip faults, likely a response to deformation partitioning caused by oblique subduction on a continental margin.

Clay composition patterns and their influence on the adhesive strength of earthen plasters

The clay fraction of earthen plasters is the part responsible for the acquisition of cohesion and adherence that they possess against deterioration factors. Adherence is the property responsible for keeping the plaster together with the wall and is influenced by the percentage content of clay as well as by its mineralogy and the heterogeneity of minerals that may be present. However, it is still unknown in depth how clay minerals perform in the adherent properties of earthen plasters when the composition is heterogeneous in the material. The objective of this study is to evaluate the incidence of the mineralogical complexity of clay mineralogy in the variability of the adherence of earth plasters. To evaluate the variability, considering that the mineralogy of the soils depends directly on the place and the formation processes, eight soils from Tucumán (Argentina) corresponding to different physiographic units were analyzed. A methodology was designed for sample preparation that allows soils to be compared through adhesion tests. They were characterized by XRD to determine their mineralogical composition and by the hydrometric method to determine their granulometry. To evaluate the adherence of mixtures made with the respective soils, it was proposed in the first instance to compensate the granulometry of the soils to equate them and, once the plasters were made, this property was evaluated through shear and pull-off tests. The results showed that they allowed us to identify that the soils presented a pattern of mineralogical composition common to all the physiographic units, made up of the Ill and K pair, the former being predominant. For this pattern, it was observed in particular that there is a positive correlation between the increase in Ill content with the increase in the adhesive strength of the plasters. Clay minerals from the Sm group also contribute to the increase in adherence when the percentage is greater than or equal to 11%. On the contrary, K and Cl do not influence the increase in adhesive strength.The clay fraction of earthen plasters is the part responsible for the acquisition of cohesion and adherence that they possess against deterioration factors. Adherence is the property responsible for keeping the plaster together with the wall and is influenced by the percentage content of clay as well as by its mineralogy and the heterogeneity of minerals that may be present. However, it is still unknown in depth how clay minerals perform in the adherent properties of earthen plasters when the composition is heterogeneous in the material. The objective of this study is to evaluate the incidence of the mineralogical complexity of clay mineralogy in the variability of the adherence of earth plasters. To evaluate the variability, considering that the mineralogy of the soils depends directly on the place and the formation processes, eight soils from Tucumán (Argentina) corresponding to different physiographic units were analyzed. A methodology was designed for sample preparation that allows soils to be compared through adhesion tests. They were characterized by XRD to determine their mineralogical composition and by the hydrometric method to determine their granulometry. To evaluate the adherence of mixtures made with the respective soils, it was proposed in the first instance to compensate the granulometry of the soils to equate them and, once the plasters were made, this property was evaluated through shear and pull-off tests. The results showed that they allowed us to identify that the soils presented a pattern of mineralogical composition common to all the physiographic units, made up of the Ill and K pair, the former being predominant. For this pattern, it was observed in particular that there is a positive correlation between the increase in Ill content with the increase in the adhesive strength of the plasters. Clay minerals from the Sm group also contribute to the increase in adherence when the percentage is greater than or equal to 11%. On the contrary, K and Cl do not influence the increase in adhesive strength.

Effects of topography, climate, mineralogy and physicochemical properties on potassium forms in various soils of Fars province, southern Iran

The relationship between potassium (K) and soil physicochemical properties can be used to understand the K cycling. Topography, as a soil forming factor, has an important effect on the soil characteristics of every region. This study was conducted to investigate K and its relationship with climate, mineralogy, and physicochemical properties in toposequences of two regions (Sepidan and Darab) in southern Iran. XRD analysing patterns showed montmorillonite, illite, chlorite, and kaolinite as diagnostic minerals of these regions. Due to being located in arid regions of Iran and lack of good rainfall, the results did not show any significant difference between the selected areas. So, climate could not be considered as an effective factor in supplying K for plants. In both regions, topography affected soil development as a soil forming factor, so that anywhere the more developed soil was observed, the more extracted K forms were found. In different physiographic units of Sepidan region, topography, by affecting soil properties through microclimate, drainage and sunshine quality, caused differences in distribution of K forms. The correlation between different K forms and soil properties in both regions because of weathering and releasing K from K-bearing minerals like illite, showed a relationship with soils finer section.

Employing Remote Sensing Technologies and Geographic Information in the Hydrological Analysis of the Hilla River Valley in Babylon Governorate

The study aims to employ geospatial technologies in the Hydrological Analysis of water basins and their importance in (Arid and Semi-arid regions). The analysis was conducted to extract the characteristics of the Terrain surface such as Degree of Slope, Direction of Flow, Accumulation of Flow, Physiographic units, water basins and other characteristics using the Digital Elevation Model (DEM), which is one of the basic components of Geographic Information Systems (GIS). Normalized Difference Water Index (NDWI) and Topographic Wetness Index (TWI), which is based on the extraction of terrain surface characteristics.

The Nature of the Pedogenic and Geoinformatics Distribution of Iron Oxides in Different Physiographic Units

The study was conducted within different physiographic units in central and northern Iraq to find out the nature of the effect of these units on the genetic distribution of iron oxides within the soil pedon. Sex Soil pedons representing the nature of the variability of the physiographic units were elected, in addition to taking 34 surface samples representing the nature of the variability of the soil units horizontally within the physiographic units to prepare maps of the spatial distribution of iron oxides based on geospatial technologies, Soil Pedons described the morphology and wavelength 5 YR for Soil pedon located within the mountainous region that was affected by iron oxides The results showed that the highest content of iron oxides was in the mountainous physiographical unit in the surface horizon Mollic horizon while the lowest content of oxides was in the physiographical unit of the river basin. The Geoinformatics distribution maps revealed 3 class of iron oxides, the low class, the medium class, and the high class. The most abundant class was the moderate class, with an estimated area of about 1051.8575.

The Nature of the Effect of the Physiographic Location on the Spectral Behavior of Soil Horizons and the Distribution of Vegetation in Central and Northern Iraq

Three soil sites in central and northern Iraq were chosen to represent the nature of three physiographic units, namely, the mountainous unit, the undulating unit, and the river basin unit, to study the effect of unit variation on the nature of soil pedological properties and its spectral behavior. The results reached a diagnosis of the nature of the variation in the characteristics of the soil represented by the variation of the morphological characteristics represented by the difference of the wavelength if 5YR prevailed for the elevation within the mountainous unit and the soil color was dark reddish-brown, while in the rest of the units it was 10YR and the predominance of the light color was affected by the different physiographic units, which was reflected in the diagnosis of the surface diagnostic horizon Mollic horizon Representing the mountainous unit, and subsurface horizon representing the Argillic horizon, and Ochric horizon, and calcic horizon within the undulating unit, as well as the high content of organic matter and iron oxides in the mountainous unit, and the values reached 34.1 grams.9.02 as well as the variability of the soil separations, as the sand separation increased in the amount representing the unit of the river basin and reached 486 g.kg and The lowest value of the spectral reflectivity was in the region representing the mountainous physiographic unit, and it reached 35% for the subsurface horizon, while the reflectivity in the rest of the units rose to 62%. Absorption bands were diagnosed at wavelengths 1400 and 1900 nm. Near-infrared is represented by wavelengths 1750-2000 and at wavelengths 2000-2500. The values of the natural variation index for plants were 0.30 with an area of 4357 km2.

The effect of agricultural exploitation and physiographic location on the soil particle size distribution for soils in Diyala Governorate

The study area was chosen to include three physiographic sites on the Diyala River, as it is located in the village of Umm Al-Azam between longitudes 33.71785 east and latitudes 44.6185 north. There are four pedons in each A physiographic unit, two of which are in cultivated sites and the other two are in unexploited agricultural sites, so the total of the studied pedons is twelve. The results of laboratory analyses showed that the sand content in the physiographic units of the cultivated soils ranged between 151.19 - 583.20 g kg-1 , as it was noted that the highest content was in the soils of river basins, while in the physiographic units of the abandoned soils, the sand content ranged between 146.62 - 600.50 g kg -1 , as its highest content was in soils River basins as well. As for the silt particle, the results showed that its content in the physiographic units of the cultivated soil ranged between 170.00 - 543.11 g kg-1 , as it was noted that its highest content was in the soils of the depression unit, while in the physiographic units of the abandoned soils, the content of the silt ranged between 54.42 - 553.01 g kg-1 , as the highest content was in pedons soils the river. As for the particle clay, its content in the cultivated physiographic units ranged between 52.10 - 375.67 g kg-1 , as the highest content was in the soils of river levee, while in the soils of the abandoned physiographic units, it ranged between 54.42 - 335.57 g kg-1 , which was the highest value for it. When soils levee of rivers . Keywords: particle, distribution, physiographic location, agricultural exploitation

Assessment of the desertification sensitivity of Northwestern El Minya Governorate, Egypt using MEDALUS model

Desertification leads to a decline in land production, resulting from biophysical interaction and human factors with temporal and spatial changes. This paper aims to evaluate the desertification sensitivity using Mediterranean Desertification and Land Use (MEDALUS) approach in the Northwestern El Minya Governorate in Egypt. The study area is one of the promising and important areas for land reclamation and developmental projects. Four indicators; climate, vegetation, management, and soil, were used in this study. Landsat 8 (OLI) satellite image 2021 was processed to calculate NDVI index to assess vegetation quality index. Then, it was classified into land cover classes to calculate the management quality index. ASTERDEM satellite data and the climate data were used in the climate quality index. Seventy soil samples were collected and analyzed for chemical and physical properties to be used for the retrieval of soil quality index. These indicators were integrated and used as input criteria in the model of desertification sensitivity. The physiographic unit extraction indicated that significant landforms were included in the study area namely; Old wadi Sediments, Peniplain, old river terraces, Shoulders, Sand sheets, Rock outcrops, and Sand dunes, Erosional Plains, Hill and Plain out wash. The obtained results showed that the severely sensitive area to desertification was represented by 86.7 % of the study area. The main factors affecting the sensitivity were climate conditions (arid, semi-arid), low soil quality and management in addition to the low vegetation cover. Furthermore, about 3% of the study area was located in the moderate sensitive class while the low sensitive area exhibits 1.06 %. Present study supports decision makers to reduce the constraining environmental conditions.

Changes in Land-Cover/Land-Use Pattern in the Fortore River Basin (Southern Italy) and Morphodynamic Implications

In Southern Italy, studies dealing with the analysis of multidecadal land-use/land-cover (LULC) changes at the basin scale are scarce. This is an important gap, considering the deep interrelationships between LULC, soil erosion, and river and coastal dynamics. This study provides a contribution in filling this gap by analyzing the LULC patterns and changes in an area of southern Italy, i.e., the Fortore River basin, which occurred between 1960 and 2018. To this end, we conducted a GIS-aided comparison and analysis of LULC data from 1960, 1990, and 2018, respectively. The LULC changes were analyzed at both the basin and the physiographic unit scale. The results showed that most of the LULC changes occurred between the 1960s and 1990s, while from the 1990s onward, great stability in LULC was evident in the basin. The obtained data were mostly coherent with national-, regional-, and basin-scale trends, although some scale-dependent discrepancies were noted. The river and shoreline dynamics fully reflected the duration and the amount of phases of the changes in LULC stability at the basin scale.

Characterization and suitability assessment of the soils of Iwo series for cocoa production in rainforest area Southwestern, Nigeria

Characterization and soil suitability assessment is a vital tool for understanding the nature and status of soils. It is one of the strategies for achieving food security as well as sustainable environment. This study was conducted to assess the suitability of the soils of Iwo series for sustainable production of cocoa. The study was carried out in 2022, in an area located approximately between 7°32' N and 7°33' N and longitudes 4°32' E and 4°40' E within the Teaching and Research Farm (T&R-F) of Obafemi Awolowo University (OAU), Kajola, Ile-Ife, Nigeria. Three profile pits were established, described and sampled with one at different physiographical units following the guideline for soil profile description according to FAO/UNESCO guideline. The soil samples collected were analyzed for particle size distribution, pH, total nitrogen, available phosphorus, exchangeable bases, and organic matter using standard method. Land characteristics obtained were matched with the crop requirements for cocoa to obtain the soils’ suitability classes using parametric method. The results showed that all the soils are well drained and deep. The texture of the soils ranged from sandy loam to sandy clay loam at the surface and sandy clay loam to clay at subsurface. Soil reaction ranged from highly acidic to slightly acidic (4.2-5.8 water and 3.9- 5.7 pHCaCl2) with low to moderate amounts of organic matter (0.4 to 1.74%) and available nitrogen (0.02-0.14%). Available phosphorus varied from 0.52-24.77 mg/kg in all the horizons in the profiles with the highest values at the surface soil horizons, an indication that soil organic matter contributes significantly to the available P in these soils. The exchangeable bases were low and the relative abundance of the exchangeable bases followed the order: Ca> Mg > Na>K at the exchangeable site. Suitability evaluation of the soils was carried out using parametric approach and the result showed that the soils of mapping units A and B are presently not suitable (N1) while mapping unit C is marginally suitable for cocoa production. With the appropriate fertility management, the soils of mapping unit A were classified as marginally suitable (S3) while soils of mapping unit B and C were classified as moderately (S2) for cocoa production. The limiting factors were mainly low soil fertility (low level of available phosphorus, macro-nutrients, nitrogen and organic matter). Therefore, combined application of organic fertilizer with inorganic fertilizers should be encouraged for optimum productivity.

A pedological study attempting to combine soil taxonomy and WRB classification systems

The study area is located in the North-Eastern part of the Nile Delta, northern of Ismailia canal and western Suez Canal. It comprises an area of about 3,058.8 km2 (728,285.38 feddans). This work aims to identify the main physiographic units and its features, as well as emphasise the importance of combining soil taxonomy (2014) and WRB classification (2022) systems. Two main physiographic units were distinguished in the study area according to the previous studies, interpretation of satellite image and digital elevation model (DEM) as well as field observations; the first consists of fluvio-marine flats and the second river terraces which include the fluvial and deltaic origin. According to field morphological descriptions as well as chemical and physical analyses, representative profiles are classified by using both Soil Taxonomy and WRB systems. The current study is the third manuscript to emphasise the importance of using both systems together in order to obtain maximum possible characteristics of the earth. Below are examples that illustrate this importance. Soils of profile No. 4 which represent the fluvio-marine soils are classified according to soil taxonomy as follows: Typical Haplosalids, fine silty, mixed, thermic. While these soils are classified according to WRB as follows: Fluvic Sodic Solonchaks (Siltic/Loamy/Clayic, Chloridic, Evapocrustic, Ochric, Hypersalic). Soils of gypsiferous which represent soils of profile No. 6 are classified according to Soil Taxonomy as: Gypsic Aquisalids, loamy over sandy, mixed, thermic, whereas the application of the WRB system reveals the following: Fluvic Calcic Gypsic Sodic Gleyic Solonchaks (Loamic, Chloridic, Hypersalic).

PEDOLOGICAL STUDY OF HILLY SOILS DEVELOPED ON BASEMENT COMPLEX TERRAIN IN MINNA, NIGER STATE, NIGERIA

A pedological characterization of hilly soils developed on basement complex terrain was carried in Minna, Niger State, Nigeria. The site was delineated into three physiographic units (positions) and designated as summit, shoulder and foot slope. Two modal profile pits were excavated in each unit to permissible depths, giving a total of six (6) profiles. The soil samples were analysed in the laboratory following standard analytical procedures. Particle size analysis showed dominance of sand over other mineral fractions irrespective of the physiographic units. Silt was next to sand in dominance and clay particle was the least in particle size. Bulk density increased with increasing soil depth in all the physiographic positions while porosity decreased down the profiles. Soil reaction (pH) ranged from moderately acid to slightly acidic in all the terrains. Organic carbon, total nitrogen and available P decreased with the increased in soil depth in all the landforms. Calcium and Magnesium were moderate while Potassium rated high in the sampled soils. The mean Na in the sampled soils rated low to moderate. Cation Exchange Capacity (CEC) in the soils rated moderate while percentage base saturation (BS) rated high. The soils are non- sodic and the electrical conductivity (EC) values are low. Thesoils of summit and shoulder were classified as Typic Paleustalfs while the footslope soils were classified as Typic Paleudalfs. The soils were classified as Plinthosols when correlated with WRB for soil resource.

Evaluation of database and some soil characteristic of Kumkale Agricultural Enterprise soils in GIS

General Directorate of Agricultural Enterprises (GDAE), which has been operating since 1994, is a state institution whose aim is to protect the gene resources as well as the production of seeds, breeding and raw materials for agriculture and agriculture-based industry. There are more than 30 agricultural enterprises established for similar purposes in Türkiye. One of these enterprises is Kumkale Agricultural Enterprise (KAE) located within the borders of Çanakkale province. The aim of this study is to reveal the current potentials of KAE lands, for which detailed studies have been made before, to create a database in Geographic Information System (GIS) and to produce various thematic maps. In this study, important soil characteristics such as slope, soil depth, surface stones, drainage, as well as soil series and physiographic units included in the survey report were mapped and the areas covered were calculated in GIS. With the digitization has determined that the agricultural enterprises lands in question are spread over an area of 7309 decares in total. In terms of soil series, the highest distribution area belongs to Karabatak series (948.2 da), while Alluvial soils (3094.8 da) have the highest distribution area in terms of physiographic units. In addition, most of the lands consist of 0-2% slope (4478.9 da), deeper than 120 cm (5936.8 da), stone-free (5677.2 da) and without drainage problems. As a result, it will be useful to examine both the temporal and spatial changes of the lands of GDAE, which has a significant production capacity in Türkiye, to make new field studies and compare them with the old survey studies in terms of guiding future studies.

Effect of Geographic Altitude on Carbon Stock in two Physiographic Units of the Reserved Forest of the Universidad Nacional Agraria de la Selva

The objective of the research was to evaluate the effect of geographic altitude on the carbon stock in two physiographic units of the Reserved Forest of the Universidad Nacional Agraria de la Selva, Tingo Maria-Huanuco. The methodology used was the field manual for the remeasurement and establishment of plots of the Amazon Forest Inventory Network (RAINFOR), for which 2 hectares were permanently established (one hectare in low and high hills) in which the diameter (greater than or equal to 10 cm) and the height of the trees were measured. Finally, the density of the wood was obtained from previous studies. The pantropical model formula was used to estimate the carbon stock. The results show that geographic altitude significantly affects carbon stock (p < 0.05) in low and high-hill forests, concluding that this may be due to differences in meteorological variables such as precipitation, temperature, and humidity.

The EPM model as a tool for analyzing the impact of dams on sediment production

The implementation of the EPM model on a time scale aims to reconstruct the production of sediment in a specific time range. The results will be compared with the evolution of the correlated physiographic unit and over the same time period.The sediment production rates analysis shows an increase in production between 1990 and 2018.The trend is in contrast with the evolution of the shoreline, in fact, the coastal physiographic unit is affected, in various sections, by a progressive and constant retreat. A possible cause could be related to dams construction along the Ofanto River.For each dam have been identified: (i) the starting year of commissioning, (ii) the area of the basin involved and (iii) an estimate of the potential impact on the production of sediment. The start-up of the San Pietro dam at the end of the 1950s and the Locone and Conza dams at the beginning of the 1990s are matched by a strong increase in the erosion process along the entire physiographic unit.The results of the study show that the use of the plug-in YES allows to map the areas of greatest impact on the production of sediment and to estimate the volume, providing important information in feasibility studies and dam management. In addition, the plug-in YES and its implementations also find potential in the implementation of VIA studies (environmental impact assessment) for the ability to assess the actual impact of the dam on the environment.

FERTILIZER-INDUCED GEOCHEMICAL FRACTIONS OF PHOSPHORUS IN FRUIT ORCHARDSS

Phosphorus (P) is essential to all known life forms because it is a key element in many physiological and biochemical processes. In this study, different physiographic units of Atabey Plain have developed soils with varying characteristics. The variability in land use and fertilizer input management causes changes in the availability and geochemical fractions of phosphorus. In this study, 29 surface soil samples (0-20 cm) were taken from various fruit orchards to investigate the plant cover-related inter-fraction mobility and availability of P as a function of soil characteristics. Sequentially extracted geochemical P fractions were: sodium bicarbonate [NaHCO3-P (organic Po, inorganic Pi, and Total Pt)], sodium hydroxide [NaOH-P (Po, Pi, and Pt)], citrate bicarbonate dithionite (CBD-P), hydrochloric acid (Ca-P), and residual (Res-P) phosphorus. In order to study the relationship of phosphorus fractions with soil properties, chemometric analyses were performed. According to the results, the average concentrations of the fractions in descending order were: Ca-P (200-1029 mg kg-1) > Res-P (55.3-449 mg kg-1 ) > CBD-P (56.5-204 mg kg-1) > NaOH-Pi (26.0-206 mg kg-1) > NaHCO3-Pi (4.38-93.4 mg kg-1) > NaOH-Po (0.55-30.0 mg kg-1) > NaHCO3-Po (0.26-7.56 mg kg-1). The added fertilizer P was likely to be converted to NaOH-P in the short term and Ca-P and/or CBD-P for a relatively longer time. It was determined that the fractal distribution of these fractions varied according to the land use pattern and soil properties such as texture, organic matter, carbonates, and iron and manganese oxide minerals.

Geospatial variability of soil physico-chemical properties of Moridhal watershed in Dhemaji district of Assam, India using Remote sensing and GIS

Remote sensing and GIS have opened new vistas towards understanding spatial variability of properties of the soil and ensuring resource use in a sustainable manner. The current study was conducted to assess the variability of physical and chemical properties of the flood-prone soils of the Moridhal watershed under Dhemaji district of Assam. The watershed was delineated using toposheets (1:50,000) and geocoded FCC (False Colour Composite) of Resourcesat-2, LISS-4. Four physiographic units of the Moridhal watershed were delineated which included upper piedmont plain, lower piedmont plain, alluvial plain and flood plain. A total of 170 geo-tagged soil samples collected from different physiographic units were analyzed for various physico-chemical properties. The assessed physico-chemical properties of the watershed showed wide spatial variability. The results showed an increasing trend in the amount of very fine sand and silt from the upper piedmont plain to the floodplain. Bulk density, particle density and porosity of the studied area varied from 1.10 to 1.67 g/cm3, 2.16 to 2.74 g/cm3 and 24.99 to 54.68 %. The pH was extremely acidic to slightly acidic and the soils were found to be moderate to high in organic carbon. The CEC of the soils ranged from 3.88 to 19.40 cmol(p+)/kg and the available nitrogen, phosphorus and potassium varied from low to high. The spatial distribution showed that about 20,408 ha soils of the study area contained more than 40-60 per cent sand, 24,833 ha soils had 20 to 40 per cent silt and 13,915 ha of soils exhibited 20 to 30 per cent clay. Nearly 97.85 % of the watershed area had medium status of available nitrogen as well as available P2O5 content, while 79.96 % of soils had low K2O content.

Geochemical and mineralogical processes leading to variation of soil characteristics on calcareous toposequence in semiarid ecosystem condition

Soils are under the influence of their formation processes at varying rates. Determining the variability and characteristics of soils due to the formation processes’ effects is vital for sustainable soil management. This study aimed to investigate soils formed on limestone and on different physiographic units (summit, shoulder, backslope and footslope) under semiarid climatic condition. That is why, the present study assessed clay mineralogy, weathering indices, mass loss/gain states, and physic-chemical properties of different profiles. It is concluded that smectite clay mineral is dominant in the profile IV located on footslope position with differences in clay mineralogy due to physiographical change. The summit physiographic unit includes the highest aggregate stability (63.74%). The soil’s field capacity and wilting point contents showed statistically significant variation with the increase in smectite clay minerals in the PIV profile on the footslope unit (p < 0.01). In addition, a positive (0.506; p < 0.05) directional relationship was found between the variability in physiographic units (from summit to footslope) and the available water content (AWC). In addition, bulk density and porosity characteristics varied depending on the particle size distribution and land use type. The soils formed on shoulder and backslope units classified as Entisol soil order are described as “not decomposed” according to the Chemical Alteration Index (CIA), Chemical Weathering Index (CIW), and Plagioclase Alteration Index (PIA) values. On the other hand, in the Inceptisol and Vertisol soils, it was determined leaching process for basic cations in the PI and PIV profiles located on the summit and footslope. As for mass balance system, the highest losses from the soil formed on the backslope whereas, the PI and PIV formed on the footslope position gains. As a result of this study, it has been revealed that soil formation process in the summit and footslope is more effective than in other physiographic units. Therefore, physico-chemical properties are mainly affected by these processes.

Differentiation sedimentological environments of soil series materials within irrigation and river basins from middle-mesopotamian

This work was carried out in East Gharaf lands which were limited with 45 50 30 " , 45 57 30 " longitudes and 32 45 15 " , 32 45 35 " latitudes . Parameters of sorting of soil material separates were used in terms of ( median diameter , inclusive graphic standared deviation бI , inclusive graphic skewness skI , kurtosis and tranformed kurtosis ) to study the statuse of soil material sorting . Stewart diagrams were used for the differenetiation of sedimentation environments .These digrams showed that , sdiments were of one main sedimentation environments ( ie river environments ) . In , addition the sediments grouped in two subenvironment clusters within the main sedimentation environment provence .These subenveronments were of fine separates sedimentation (river sediment) and medium to coarse separates sedimentation (irrigation sediments) . Both sediments are recent and local physiographic units .Sediments of soil materials were characterized and correlated to their sedimentation environments by the use of triangular diagrams and illustrated in terms of the relative percentages of light minerals ( chert , feldspars , biotiet ) fractions and heavey minerals (pyroxenes, garnet , chlorite) in order to assure their sedimentation environments . Accordingly , it can be suggested that , the use of light minerals gave better distinction and differentiation between sediments of river and irrigation basins . Also ,the soil use of separetes were the best in the differentiation between the subenvironments of sedimentation of river and irrigation sediments .

Carbon stocks across different environments, disturbance regimes, and stand age in Fitzroya cupressoides forests, the longest-lived species of the southern hemisphere

Forest disturbances influence Fitzroya cupressoides forest structure and carbon stocks at multiple spatial and temporal scales. Natural disturbances such as landslides and volcanism affect and give rise to the mostly pristine Fitzroya stands present in the Andean cordillera. On the other hand, mostly human-caused fires and logging have been the main processes shaping the structure of Fitzroya stands in the Coastal range and of Fitzroya small remnants in the Central depression. The main goal of this study was to assess the carbon stocks and accumulation rates of Fitzroya forest stands according to their development stage under different disturbance regimes and environmental conditions given by the three physiographic units where the species grows (Coastal range, Central depression, and Andean range). The site selection included an age sequence of stands, known as a chronosequence approach. We identified Fitzroya post-disturbance stands in three different stages of development: young forest stage (mean stand age of the main cohort ≤ 200 years old), mature forest stage (200–800 years old), and old growth forest stage (800–1,500 years old). The following biomass components were considered: living standing trees, dead standing trees (snags), and logs from dead trees laying on the ground (coarse woody debris). Old-growth Fitzroya forests reached a mean total carbon stock (standing live trees, snags, and coarse woody debris) of 507, 279, and 331 Mg C ha−1 in the Andean and Coastal ranges, and Central depression, respectively. Fitzroya cupressoides contributes, in average, more than 80% to the total carbon stock in the Andean and Coastal ranges, and 63% in the Central depression. The remainder corresponds mainly to Nothofagus spp. The high carbon stocks in old-growth stands in the Andean range are explained by Fitzroya longevity, larger size, wood decay resistance, and the low recurrence of volcanic events. Carbon accumulation rates differ between the forests in the three physiographic units (Central depression&amp;gt;Andean range&amp;gt;Coastal range), mainly due to the different growth rates and environmental conditions present in each unit. In the context of climate change, conserving old-growth stands with large biomass and carbon stocks and restoring Fitzroya forests should be recognized as a key contribution toward national and global goals to mitigate global warming.