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THIS RESEARCH aims to create and analyze thematic soil maps for promising areas for agricultural expansion along the northwest coast of Egypt. The study area is 3151.671 km² and consists of a plateau and elevated areas merging into coastal lowlands. Remote sensing data were used with a digital elevation model to map the physiographic units and characterize land surface features. Five different physiographic entities are recognized; each mostly associated with the soil sub-great groups Typic Haplocalcids and Typic Torripsamments. Data collected through land survey and laboratory analysis were used to create thematic soil layers that were analyzed to determine land factors that limit agricultural development. The results showed that the land surface factors hinder agricultural development due to the steep slope and undulation of the land surface. Analysis of thematic soil maps showed that agricultural development in the region is mainly constrained by coarse soil texture, shallow soil depth, high CaCO3 content, and low CEC. To achieve agricultural sustainability in the region, improved drainage, organic fertilization, and crop selection are required. [ABSTRACT FROM AUTHOR]

To date, 55 species of bats have been recorded over a wide range of altitudes from 64 to 4,154 m above sea level (a.s.l.) in Nepal. One third of Nepal, including eight protected areas, most of the Higher Mountain region and the western part of the country, has yet to be surveyed. In this study, mist netting, harp trapping, roost and acoustic surveys revealed a total of 34 species of bats belonging to 22 genera from nine districts of Nepal. Coelops frithii and Harpiocephalus harpia were noted for the first time from the country. Bats were recorded at altitudes from 240 to 3,232 m, with 25 species recorded from middle elevation ranges (1,001–2,000 m a.s.l.), 21 species from higher elevation ranges (2,001–3,232 m a.s.l.), and 20 species from lower elevation ranges (240–1,000 m a.s.l.). The distribution patterns across different ranges were species-specific (e.g., irregular in Myotis csorbai, hump-shaped in Submyotodon caliginosus, and linear in Nyctalus noctula), with high species richness observed at elevations from 501 to 1,000 m a.s.l. (22 species), followed by 1,001–1,500 m a.s.l. (21 species). These data are expected to guide the designation of new survey and monitoring areas in the future. Consequently, further detailed surveys and monitoring, particularly in western Nepal and the Higher Mountain regions, are likely to yield new distribution records of bats, both nationally and globally. [ABSTRACT FROM AUTHOR]

Background and aims – In spite of their proximity to the coasts, the flora of the islands and islets of the Algerian coasts has been poorly studied. This work is the first to provide an overall view of the richness and the determinants of the Algerian island flora. Material and methods – The study is based on a compilation of original floristic data. Two classifications of 30 islands and islets were derived from PCA and HCPC performed on the species occurrence matrix and on a matrix of flora descriptors including species richness, functional traits (life form, seed dispersal, pollination), and biogeographic range. We performed an RDA to explain the variation in flora characteristics by a set of physiographic (longitude, latitude, elevation, area, isolation, steepness index, and area/perimeter ratio) and biotic (seabird density and human presence) variables. Key results – The floristic inventory encompassed a total richness of 295 vascular plant taxa (including subspecies and varieties) on the 30 studied sites. Five main groups of islands and islets can be distinguished based on vegetation composition and three from flora descriptors. RDA model selection revealed that the combination of four variables (seabird density, area, latitude, and longitude) explained 26.6% of the variation in flora characteristics. Taken alone, the density of yellow-legged gull colonies and the island area were the main drivers of this variation. Results showed that floristic richness was associated with larger island area and higher seabird density, the importance of some plant functional traits, such as zoochory and entomogamy, and with a higher proportion of Eurasian holarctic species. Conclusion – In the context of island flora conservation, some of these small islands of Algeria can be considered as “modern refuges” from human pressures, and this is particularly important in the context of Mediterranean ecosystems characterised by a quasi-permanent human impact in various habitats. Two new important plant areas (IPAs) for Algeria are proposed following the results of these floristic inventories [ABSTRACT FROM AUTHOR]

In the Himalayas, the lives and livelihoods of millions of people are sustained by water resources primarily depending on the moisture brought by Western Disturbances and Indian Summer Monsoon. In the present study, a network of 12 precipitation stations was established across the Kashmir Valley to understand the spatial and meteorological factors controlling precipitation isotopes. Temperature and relative humidity are dominant meteorological factors, whereas altitude, proximity to forest canopy, land use/land cover, windward and leeward sides of the mountains are the main physical factors influencing precipitation isotopes. The study suggests that the Mediterranean Sea and nearby water bodies along with continental recycling are the dominant sources of moisture from October to May, while the Arabian Sea, Bay of Bengal and continental recycling are the main sources of moisture from June to September. However, some precipitation events from October to May collect moisture from the Arabian Sea and some precipitation events from June to September collect moisture from the Mediterranean Sea. The occasional passage of Western Disturbances in summer merging with the Indian Summer Monsoon yields heavy to very heavy precipitation. The study provides a better understanding of complex spatial and meteorological phenomena controlling precipitation isotopes across the Western Himalayas. [ABSTRACT FROM AUTHOR]

Many distinct glacial episodes in the past ~1 million years in the Central Lowlands of North America left behind a patchwork of glaciated landscapes of different ages and formed through different glacial, paraglacial, and proglacial processes. Herein, we synthesize and reconcile diverse data sources across nine states in the Central Lowlands to create a generalized landform regions map, incorporating information from surficial geology, age-constrained glacial boundaries, soil properties and parent material, and topography. The resulting map presents regions of till plains, moraines, outwash plains, and glacial lakes with ages ranging from 10.2 cal ka BP to greater than 500 cal ka BP. This new map improves on regional perspectives of the glaciated Central Lowlands by modifying and reconciling boundaries to agree with a variety of spatial data sources with finer detail. This refined map enables a more accurate spatial analysis of the landform regions by reducing noise from imprecise boundaries.

Pollen and sediment data from a 10.5 m-deep alluvial exposure and a secondary tributary exposure at Upper Arroyo, a seasonal river, in Saltillo, Mexico, were examined with the aim of reconstructing the vegetation and environmental history during the Holocene as a whole. The role of climate change in Chihuahuan Desert flora development after 8800 BP was assessed, in addition to more local physiographic factors, such as erosion and accumulation, soil development and denudation, and hydrological entrenchment. Climate change appeared to have been a principal agent of vegetation change in the Early and Middle Holocene, with a periodic expansion of desert vegetation. A reduction in the environmental carrying capacities for mesophytic flora according to physiographic factors, such as soil erosion and channel entrenchment, was then identified after 2300 BP, also promoting azonal ecological niches for xerophytic vegetation in southern Coahuila, Mexico, that persist despite modern variations in precipitation. [ABSTRACT FROM AUTHOR]

IntroductionPhysiography is a part of earth science studies in which the physical characteristics of the drainage basin such as area, perimeter and relief, slope, direction, etc. are studied. The studies that examine the physical characteristics and shape of a basin are called Physiography. Knowledge of the physiographic characteristics of a basin along with information about the climatic conditions of the region can provide us with a relatively accurate image of the quantitative and qualitative function of the hydrological system of that basin (Pitlick, 1994). The increase in the rank of waterways in a drainage basin is under the influence of various geomorphological, geological, and climatological ecosystems and contexts. In dealing with open systems, the researchers’ assumption is usually on the effectiveness of specific and accessible vectors and the evaluation of the system's behavior in relation to those vectors. The area of study in this research includes Iran. Iran with an area of about 1648195 square kilometers is approximately located between 25-40 degrees north latitude and 44-64 degrees east longitude. Materials and MethodsIn this study, the accuracy of physiographic relationships in the basins was discussed. The existing relationships and the connection between them represent the relation of physiographic characteristics of the basin. In dealing with open systems, the researchers’ assumption is usually on the effectiveness of specific and accessible vectors and the evaluation of the system's behavior in relation to those vectors. Accordingly, in this study, the increase in the rank of the waterways drainage basin of Iran in the form of 984 sub-basins was investigated in terms of the bifurcation ratio, total length of waterways, the total average of waterways, and basin area. The relation between the equal rank of waterway and drainage basin area and also the relation between specific retention constant and slope and drainage density are among the physiographic characteristics of the drainage basin that were evaluated in this study. For this purpose, first, the layer of main rivers and waterways was prepared from DEM 30*30 extracted from the SRTM satellite. After extraction of the waterway in Arc GIS 10.3 software, Iran's rivers were ranked based on the Horton-Strahler theory. The relation between the equal rank of waterway and drainage basin area and also the relation between specific retention constant and slope and drainage density are among the physiographic characteristics of the drainage basin that were evaluated in this essay. DiscussionIn the drainage basin of Iran, a regression equation was established between the ‘area’ as an independent variable and the sum of flow ranks as a dependent variable, and the obtained equation responded positively to this hypothesis with a favorable level of significance. The amount of the explanation coefficient of most sub-basins is more than 0.99, which indicates the great effectiveness of the expanse of the basins on the sum of the ranks of rivers flow. The lowest explanation coefficient is in the Abarkooh-Sirjan basin (0.89) and then in Dar-Anjir Desert sub-basins (0.92) (probably due to the basins being dry and playa), Aras (due to having just one bank) And Haraz-Qarah Su (0.96), and Sefidrud-Haraz (0.97) (due to the different climate of the basins), respectively. The bifurcation ratio has an inverse relationship with the ranks so that as the waterway rank increases, the bifurcation ratio coefficient decreases.The highest percentage belongs to the Sefidrud-Haraz (82%), Gavkhouni 72%), and Namak Lake (62%) basins. The common feature of the three basins is that their final drain is located in a corner of the basin and not in the center. Siahkuh Desert sub-basins (35%), Bandar Abbas-Sadich (36%), Karkheh and Abarkooh-Sirjan (37%) have the lowest frequency percentage of high ranks. In the drainage basin, a regression equation was established between the area and equal ranks according to their frequency. In this equation, the area was the independent variable and the bifurcation ratio was the dependent variable and according to the level of significance obtained from the equation, the drainage basin responded positively to the hypothesis. Basins with smaller areas also had smaller bifurcation ratios. The highest explanation coefficients belong to Qarah-Su- Gorganrood (99%) and Dur-Anjir Desert (98%) sub-basins, and the lowest explanation coefficients belong to Sefidrud and Hamun-e Jaz-Murian (50%), Hamun-e Mashekl (54%), Urmia (59), and Helleh (62%) sub-basins.The flow length of each rank is measured and categorized in all basins. The prevailing result is the existence of a negative relationship between total flow length and rank. A regression equation was established between retention constant and slope, and regression equations were estimated with a positive procedure. In this examination, the slope was considered the independent variable and the retention constant was considered the dependent variable. Some basins were excluded from the examination, most likely due to the topographic and lithological effects of the basins that have changed the specific retention constant. Basins may be more expanded in the mound area, reducing drainage density in these areas. Even among the basins where acceptable regression equations have been obtained, the explanations coefficient varied between 50% (Hamun-Helmand, Abarkooh-Sirjan, Sefidrud) up to a maximum of 79% (Gavkhouni) and most of them had been between 50% and 60%. ConclusionThere is a direct relationship between the two parameters that is, the sum of the rank of waterways in a drainage basin and the area of the drainage basin of Iran so that in most drainage basins the explanation coefficient of these two parameters is estimated to be 99%. In the drainage basin of Iran, the amount of the explanation coefficient of the bifurcation ratio and increasing the rank of rivers varies from 35% in the Siahkuh Desert basin to 82% in the Sefidrud drainage basin. The area of the basin with a 99% explanation coefficient may affect the bifurcation ratio. In some basins of Iran that have active tectonics or rivers are captured or diverted, sometimes the flow length is fewer in the lower ranks than in the higher ranks. Provided that the topography of the basin is balanced over time, by increasing the rank of waterways, the flow length average increases in the same rank. The assumption that as much as the retention constant of the basin increases then the drainage density of the basin decreases, can be generalized in most of the drainage basins of Iran with an explanation coefficient higher than 90%. Keywords: Physiography, Specific Retention, River Ranking, Drainage Basin. References- Ali, U., & Ali, S. A. (2014). Analysis of drainage morphometry and watershed prioritization of Romushi-Sasar catchment, Kashmir valley, India using remote sensing and GIS technology. International Journal of Advanced Research, 2(12), 5-23.- Elmi Zadeh, H., Mah Peykar, O., & Sadatmand, M. (2014). Investigation of fractal theory in river geomorphology (case study: Zarrineh River). Journal of Quantitative Geomorphological Research, 3(2), 130-141 (in Persian).- Hack, J. T. (1975). Dynamic equilibrium and landscape evolution. Theories of Landform Development, 1, 87-102.- Horton, R. E. (1945). Erosional development of streams and their drainage basins; hydro physical approach to quantitative morphology. Journal of Geological Society of America Bulletin, 56(3), 275-370.- Lanzoni, S., Ferdousi, A., & Tambroni, N. (2017). River banks and channel axis curvature: Effects on the longitudinal dispersion in alluvial rivers. Journal of Advances in Water Resources, 113, 55-72.- Nautiyal, M. D. (1994). Morphometric analysis of a drainage basin using aerial photographs: A case study of Khairkuli Basin, District Dehradun, UP. Journal of the Indian Society of Remote Sensing, 22(4), 251-261. - Oruonye, E. D., Ezekiel, B. B., Atiku, H. G., Baba, E., & Musa, N. I. (2016). Drainage basin morphometric parameters of River Lamurde: Implication for hydrologic and geomorphic processes. Journal of Agriculture and Ecology Research International, 5(2), 1-11.- Perasad, G. (2009). Trends and techniques of geomorphology. Translated by Mehran Maghsoudi and Mohammad Taher Khani. Tehran: Selected Publications (in Persian).- Pitlick, J. (1994). Relation between peak flows, precipitation, and physiography for five mountainous regions in the western USA. Journal of Hydrology, 158(3-4), 219-240.- Raj, P. N., & Azeez, P. A. (2012). Morphometric analysis of a tropical medium river system: A case from Bharathapuzha River Southern India. Open Journal of Modern Hydrology, 2(4), 91-98.- Schumm, S. A. (1956). Evolution of drainage systems and slopes in badlands at Perth Amboy, New Jersey. Geological Society of America Bulletin, 67(5), 597-646.- Singh, V., & Singh, U. C. (2011). Basin Morphometry of Maingra River, district Gwalior, Madhya Pradesh, India. International Journal of Geomatics and Geosciences, 1(4), 891-902.- Wang, G., Gertner, G., Fang, S., & Anderson, A. B. (2003). Mapping multiple variables for predicting soil loss by geostatistical methods with TM images and a slope map. Journal of Photogrammetric Engineering and Remote Sensing, 69(8), 889-898.

The aim of the study was to determine the most important environmental factors (topography, climate, and soil) affecting changes in production and canopy cover of plant variations and to prepare prediction maps, based on the most important factor, in semi-steppe rangelands of Hir-Baghrou, Ardabil province, Iran. First, by detecting the vegetation types and different classes of environmental factors, the production and canopy cover were estimated in 1-m2 plots at full flower stage of dominant species. Then, to determine the most important environmental factors, affecting the production and canopy cover changes, the principal component analysis (PCA) was used. For modeling, first, the correlation between the most effective environmental factors was obtained from the PCA. Then, the highly correlated factors were eliminated and the quadratic polynomial models were obtained. Finally, the obtained models were simulated in GIS. The results of the PCA showed that the first six components with 71.65% had the greatest effect on the production and canopy cover changes. Based on the root mean squared error (RMSE), simulating maps of production (RMSE=0.76) and canopy cover (RMSE=0.48) by effective factor (annual precipitation) showed the highest accuracy. The results of this study can be used to manage the rangelands of Ardabil province to create a balance between supply and demand of production and also to balance carbon.

A physiographic-based multilinear regression model supported by GIS was developed to estimate spatial rainfall variability in the Southwest Iberian Peninsula. The area study includes a wide diversity of landscape features and comprises four Portuguese regions and one Spanish province (totalizing 28,860 km2). The region suffers a very strong Mediterranean influence, with a major cleavage between winter and summer seasons. Thus, the analysis was carried out separately for the wet (October to March) and dry (April to September) semesters. From an initial set of 10 explanatory physiographic variables, five were selected to be used in the multilinear regression, as they allowed generating models by map algebra that fitted well with the last 40 years of monthly rainfall data records. These records were obtained from 163 weather stations, filtered from an initial set of 230 (142 stations in Portugal and 88 in Spain). The correlation between the physiographic-based multilinear regression model and a model obtained by interpolation from rainfall historical data showed to be good or very good in approximately 75% of the area under study. Results show that physiographic-based models can be effectively used to estimate rainfall where there is a lack of rain gauges, or to densify spatial resolution of rainfall between rain gauges. [ABSTRACT FROM AUTHOR]

Introduction: The Zagros forests, which are one of Iran's most important forest ecosystems, contain a diversified vegetation that includes trees, shrubs, and herb-layer species. Identification and precise knowledge of their ecological role in this ecosystem can help in natural resources protection and sustainable development. In order to study the effects of physiographic factors (aspect, slope, and elevation) on the woody plants species diversity and also soil carbon stock in the central Zagros, the maple tree (Acer monspessulanum Var. cinerscens) forest in Hashtadpahlu region which is located in Lorestan was selected. Material and methods: Within the forest, 37 circular plots, each measuring 1000 m², were placed systematicrandomly for this purpose. Richness and diversity indices were calculated for woody species within plots. Soil samples were taken from a depth of 0-30 cm to measure the quantity of carbon stock in the soil and the value of soil organic carbon and bulk density for soil samples were measured. Results and discussion: In this forest, 11 different woody plant species (trees and shrubs) from seven different families were investigated. The results showed that the highest diversity of shrub species was observed in the northern aspect and the lower slopes (class of 5-20%), while the elevation has no significant effect on the shrub diversity. Also, the physiographic factors had no significant effect on shrub species richness and tree species diversity and richness. The most soil carbon stock was measured in the eastern aspect while the other physiographic factors had no significant effect on carbon stock. The reduced carbon supply on the northern slopes relative to the rest of the slopes could be a result of heavy grazing, low density and poor vegetative quality of woody species, reduction of tree litter and other plant species and climatic conditions in this slope. As a result, the most important factors impacting the number of species diversity indices in the Acer forest are the aspect and slope. Conclusion: The richness and diversity of woody species in the Acer sp. forest are appropriate and physiographic factors have played an important role in the values of their indices. Physiographic parameters have an impact on the carbon stock of the soil. As a result, environmental variables should be considered in the management of Zagros forests due to its extensive distribution. [ABSTRACT FROM AUTHOR]

Intensifying permafrost thaw alters carbon cycling by mobilizing large amounts of terrestrial substrate into aquatic ecosystems. Yet, few studies have measured aquatic carbon fluxes and constrained drivers of ecosystem carbon balance across heterogeneous Arctic landscapes. Here, we characterized hydrochemical and landscape controls on fluvial carbon cycling, quantified fluvial carbon fluxes, and estimated fluvial contributions to ecosystem carbon balance across 33 watersheds in four ecoregions in the continuous permafrost zone of the western Canadian Arctic: unglaciated uplands, ice‐rich moraine, and organic‐rich lowlands and till plains. Major ions, stable isotopes, and carbon speciation and fluxes revealed patterns in carbon cycling across ecoregions defined by terrain relief and accumulation of organics. In previously unglaciated mountainous watersheds, bicarbonate dominated carbon export (70% of total) due to chemical weathering of bedrock. In lowland watersheds, where soil organic carbon stores were largest, lateral transport of dissolved organic carbon (50%) and efflux of biotic CO2 (25%) dominated. In watersheds affected by thaw‐induced mass wasting, erosion of ice‐rich tills enhanced chemical weathering and increased particulate carbon fluxes by two orders of magnitude. From an ecosystem carbon balance perspective, fluvial carbon export in watersheds not affected by thaw‐induced wasting was, on average, equivalent to 6%–16% of estimated net ecosystem exchange (NEE). In watersheds affected by thaw‐induced wasting, fluvial carbon export approached 60% of NEE. Because future intensification of thermokarst activity will amplify fluvial carbon export, determining the fate of carbon across diverse northern landscapes is a priority for constraining trajectories of permafrost region ecosystem carbon balance. Plain Language Summary: Freshwaters are a main component of the global carbon cycle and climate. Yet, their role in climate change is uncertain in permafrost regions, where thaw is releasing large amounts of carbon and enabling production of climate‐warming greenhouse gases. To reduce uncertainty, we measured stream chemistry and carbon fluxes across four ecoregions including a global hotspot of permafrost thaw in the western Canadian Arctic. Comparing across ecoregions, lowlands were strong sources of biological carbon dioxide and methane to the atmosphere; mountain rivers ferried products from chemical rock weathering downstream; and streams affected by permafrost thaw‐induced wasting transported large amounts of particulate carbon. Typical of northern ecosystems, carbon fluxes in non‐thaw‐affected streams were equivalent to 6%–16% of carbon uptake by terrestrial vegetation. However, in watersheds affected by thaw‐induced wasting, carbon fluxes were up to 100 times higher and approached 60% of vegetation carbon uptake. Together, these findings reveal that thermokarst‐susceptible terrains are poised to emerge as a significant component of the Arctic ecosystem carbon balance and global climate feedbacks, due to hydrologic carbon fluxes that will intensify as permafrost thaw accelerates. Key Points: Permafrost landscape history regulates fluvial carbon (C) sources and export across a transect of continental glaciation and thermokarstFluvial C flux equaled 6%–16% of vegetation C uptake in most watersheds and 60% in those affected by permafrost thaw‐driven mass wastingThaw‐susceptible terrains will be significant to Arctic ecosystem carbon balance as permafrost thaw and hydrologic carbon fluxes intensify [ABSTRACT FROM AUTHOR]

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The transformation of rocks and organic inputs into parent material and soil is a dynamic process controlled by physical, chemical and biological factors. In this process, the parent material, climate, topography, organism and time are known as formation factors. The differences in physiography cause variability in soil properties with the effect of other formation factors. In this study; It is aimed to reveal how the physiographic variability is reflected in the profile morphology and the statistical effects of this reflection on soil properties. Morphological descriptions of four soil profiles (PI, PII, PIII, PIV) were made in the north-south direction to represent the varying physiographic units (shoulder, toeslope, backslope) and some physical and chemical properties of soil samples taken on the basis of the horizon were determined. In addition, the variables in soil properties were evaluated with some statistical parameters. As a result of the study, all profiles were classified as Lithic Xerorthent / Petrocalcic Leptosol. While the profiles on the upper and lower skirts have similar characteristics, it has been determined that the profile in the low plain differs in terms of horizon depth and thickness, soil color, lime content, texture and water characteristics. With this study, it has been revealed that the relationship can be explained more clearly as a result of the evaluation of the change in soil properties with statistical approaches.

Landforms of the United States (1939) by Erwin Raisz is one of the best examples of cartographic excellence depicting the landscape based on underpinning geological structure. With the block diagram as the foundation for landform mapping, this paper details the development of the landform map comparing works and lives of two of the most prominent physiographic landform cartographers, Erwin Raisz and Armin K. Lobeck, who each had Dr. Douglas Johnson as a PhD advisor at Columbia University. Comparing the 1921 Physiographic Diagram of the United States by Lobeck with the 1939 Raisz map, this paper argues that Raisz far exceeded Lobeck in the articulation of the landscape by way of the map. [ABSTRACT FROM AUTHOR]

A study was conducted in lower Shiwaliks of Punjab, India to study the soil organic carbon (SOC) stock variation in hill, piedmont plain and alluvial plain regions of Punjab, and further to investigate the SOC variability down the slope in the lower Shiwaliks region of Punjab. The SOC fractions viz. very labile carbon, labile carbon, less labile carbon and recalcitrant were determined using standard methodologies. The total SOC stock in 0–60 cm soil depth was highest in plain region (31.81 Mg ha−1), followed by piedmont (23.43 Mg ha−1) and lowest in hill region (22.86 Mg ha−1). Whereas, the SOC concentration in surface layer was highest in foot slope (5.76 g kg−1) followed by mid slope (4.14 g kg−1) and lowest in up slope (2.32 g kg−1). Among the SOC fractions the average labile carbon content in soil samples was found in the order, hills (0.81 g kg−1) > piedmonts (0.73 g kg−1) > plains (0.50 g kg−1). The soil bulk density (Db) was higher in the plain than that of piedmont and hills. Moreover, a similar trend is observed in case of water holding capacity. Regression analysis has revealed significant relationship between Db and SOC stock at p

Pollen and sediment data from a 10.5 m-deep alluvial exposure and a secondary tributary exposure at Upper Arroyo, a seasonal river, in Saltillo, Mexico, were examined with the aim of reconstructing the vegetation and environmental history during the Holocene as a whole. The role of climate change in Chihuahuan Desert flora development after 8800 BP was assessed, in addition to more local physiographic factors, such as erosion and accumulation, soil development and denudation, and hydrological entrenchment. Climate change appeared to have been a principal agent of vegetation change in the Early and Middle Holocene, with a periodic expansion of desert vegetation. A reduction in the environmental carrying capacities for mesophytic flora according to physiographic factors, such as soil erosion and channel entrenchment, was then identified after 2300 BP, also promoting azonal ecological niches for xerophytic vegetation in southern Coahuila, Mexico, that persist despite modern variations in precipitation.

Introduction Physiography is a part of earth science studies in which the physical characteristics of the drainage basin such as area, perimeter and relief, slope, direction, etc. are studied. The studies that examine the physical characteristics and shape of a basin are called Physiography. Knowledge of the physiographic characteristics of a basin along with information about the climatic conditions of the region can provide us with a relatively accurate image of the quantitative and qualitative function of the hydrological system of that basin (Pitlick, 1994). The increase in the rank of waterways in a drainage basin is under the influence of various geomorphological, geological, and climatological ecosystems and contexts. In dealing with open systems, the researchers’ assumption is usually on the effectiveness of specific and accessible vectors and the evaluation of the system's behavior in relation to those vectors. The area of study in this research includes Iran. Iran with an area of about 1648195 square kilometers is approximately located between 25-40 degrees north latitude and 44-64 degrees east longitude. Materials and Methods In this study, the accuracy of physiographic relationships in the basins was discussed. The existing relationships and the connection between them represent the relation of physiographic characteristics of the basin. In dealing with open systems, the researchers’ assumption is usually on the effectiveness of specific and accessible vectors and the evaluation of the system's behavior in relation to those vectors. Accordingly, in this study, the increase in the rank of the waterways drainage basin of Iran in the form of 984 sub-basins was investigated in terms of the bifurcation ratio, total length of waterways, the total average of waterways, and basin area. The relation between the equal rank of waterway and drainage basin area and also the relation between specific retention constant and slope and drainage density are among the physiographic characteristics of the drainage basin that were evaluated in this study. For this purpose, first, the layer of main rivers and waterways was prepared from DEM 30*30 extracted from the SRTM satellite. After extraction of the waterway in Arc GIS 10.3 software, Iran's rivers were ranked based on the Horton-Strahler theory. The relation between the equal rank of waterway and drainage basin area and also the relation between specific retention constant and slope and drainage density are among the physiographic characteristics of the drainage basin that were evaluated in this essay. Discussion In the drainage basin of Iran, a regression equation was established between the ‘area’ as an independent variable and the sum of flow ranks as a dependent variable, and the obtained equation responded positively to this hypothesis with a favorable level of significance. The amount of the explanation coefficient of most sub-basins is more than 0.99, which indicates the great effectiveness of the expanse of the basins on the sum of the ranks of rivers flow. The lowest explanation coefficient is in the Abarkooh-Sirjan basin (0.89) and then in Dar-Anjir Desert sub-basins (0.92) (probably due to the basins being dry and playa), Aras (due to having just one bank) And Haraz-Qarah Su (0.96), and Sefidrud-Haraz (0.97) (due to the different climate of the basins), respectively. The bifurcation ratio has an inverse relationship with the ranks so that as the waterway rank increases, the bifurcation ratio coefficient decreases. The highest percentage belongs to the Sefidrud-Haraz (82%), Gavkhouni 72%), and Namak Lake (62%) basins. The common feature of the three basins is that their final drain is located in a corner of the basin and not in the center. Siahkuh Desert sub-basins (35%), Bandar Abbas-Sadich (36%), Karkheh and Abarkooh-Sirjan (37%) have the lowest frequency percentage of high ranks. In the drainage basin, a regression equation was established between the area and equal ranks according to their frequency. In this equation, the area was the independent variable and the bifurcation ratio was the dependent variable and according to the level of significance obtained from the equation, the drainage basin responded positively to the hypothesis. Basins with smaller areas also had smaller bifurcation ratios. The highest explanation coefficients belong to Qarah-Su- Gorganrood (99%) and Dur-Anjir Desert (98%) sub-basins, and the lowest explanation coefficients belong to Sefidrud and Hamun-e Jaz-Murian (50%), Hamun-e Mashekl (54%), Urmia (59), and Helleh (62%) sub-basins. The flow length of each rank is measured and categorized in all basins. The prevailing result is the existence of a negative relationship between total flow length and rank. A regression equation was established between retention constant and slope, and regression equations were estimated with a positive procedure. In this examination, the slope was considered the independent variable and the retention constant was considered the dependent variable. Some basins were excluded from the examination, most likely due to the topographic and lithological effects of the basins that have changed the specific retention constant. Basins may be more expanded in the mound area, reducing drainage density in these areas. Even among the basins where acceptable regression equations have been obtained, the explanations coefficient varied between 50% (Hamun-Helmand, Abarkooh-Sirjan, Sefidrud) up to a maximum of 79% (Gavkhouni) and most of them had been between 50% and 60%. Conclusion There is a direct relationship between the two parameters that is, the sum of the rank of waterways in a drainage basin and the area of the drainage basin of Iran so that in most drainage basins the explanation coefficient of these two parameters is estimated to be 99%. In the drainage basin of Iran, the amount of the explanation coefficient of the bifurcation ratio and increasing the rank of rivers varies from 35% in the Siahkuh Desert basin to 82% in the Sefidrud drainage basin. The area of the basin with a 99% explanation coefficient may affect the bifurcation ratio. In some basins of Iran that have active tectonics or rivers are captured or diverted, sometimes the flow length is fewer in the lower ranks than in the higher ranks. Provided that the topography of the basin is balanced over time, by increasing the rank of waterways, the flow length average increases in the same rank. The assumption that as much as the retention constant of the basin increases then the drainage density of the basin decreases, can be generalized in most of the drainage basins of Iran with an explanation coefficient higher than 90%. [ABSTRACT FROM AUTHOR]

Many distinct glacial episodes in the past ~1 million years in the Central Lowlands of North America left behind a patchwork of glaciated landscapes of different ages and formed through different glacial, paraglacial, and proglacial processes. Herein, we synthesize and reconcile diverse data sources across nine states in the Central Lowlands to create a generalized landform regions map, incorporating information from surficial geology, ageconstrained glacial boundaries, soil properties and parent material, and topography. The resulting map presents regions of till plains, moraines, outwash plains, and glacial lakes with ages ranging from 10.2 cal ka BP to greater than 500 cal ka BP. This new map improves on regional perspectives of the glaciated Central Lowlands by modifying and reconciling boundaries to agree with a variety of spatial data sources with finer detail. This refined map enables a more accurate spatial analysis of the landform regions by reducing noise from imprecise boundaries. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the most important environmental factors (topography, climate, and soil) affecting changes in production and canopy cover of plant variations and to prepare prediction maps, based on the most important factor, in semi-steppe rangelands of Hir-Baghrou, Ardabil province, Iran. First, by detecting the vegetation types and different classes of environmental factors, the production and canopy cover were estimated in 1-m2 plots at full flower stage of dominant species. Then, to determine the most important environmental factors, affecting the production and canopy cover changes, the principal component analysis (PCA) was used. For modeling, first, the correlation between the most effective environmental factors was obtained from the PCA. Then, the highly correlated factors were eliminated and the quadratic polynomial models were obtained. Finally, the obtained models were simulated in GIS. The results of the PCA showed that the first six components with 71.65% had the greatest effect on the production and canopy cover changes. Based on the root mean squared error (RMSE), simulating maps of production (RMSE=0.76) and canopy cover (RMSE=0.48) by effective factor (annual precipitation) showed the highest accuracy. The results of this study can be used to manage the rangelands of Ardabil province to create a balance between supply and demand of production and also to balance carbon. [ABSTRACT FROM AUTHOR]

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The objective of this article was to study the effect of geographical features and geological formations on some physicochemical properties of soils in order to better identify the soil and optimize land management for sustainable agriculture in the southern part of the plain. Urmia, with an area of 35000 (ha) in the province of Western Azarbaijan, Iran. In this investigation, satellite images, aerial photographs, topographic and geological maps were used to identify and distinguish different land forms, soil series classified based on geomorphological and geophysical methods. 30 soil profiles were drilled and the FAO standard dimensions were described. Samples were taken from five soil profiles in each genetic horizon and transferred to the laboratory. The soil moisture and temperature regime was determined as Xeric and Mesic. The soils of the studied area were classified as Fluventic Inceptisols and grid subgroups. The most dominant formations in the Barandoz and Ghasemlou river basins were limestone and lime, which is one of the determining factors in rock formation in different soils in the study area. On the other hand, physiography and topography have also played an important role, so that the upper terraces have more developed soils and some sloping regions have younger and less developed soils. With the decrease in height and proximity to Lake Urmia, the effect of the groundwater level and its salinity on the profiles is evident. Meanwhile, the river bank has young and uncovered soils due to the sediments of the current era.

One of the uncontrolled and very fast spring cultivation activity areas in the recent years is found in tectonic-karstic depression of the Elmalı district of Antalya province in the western part of the Taurus Mountain Range. The main aim of this study is to determine temporal and spatial changes in the spreading of the greenhouse areas on three different physiographic units in the Elmalı Depression. Here in the Eskihisar region, Pansharped satellite name and spatial resolution in 2009 and 2016 respectively, GeoEye-1 0.5 m and WorldView-3 0.4 m, in the Gölova-Çukurelma region with 0.6m GeoEye-1 satellite images with 0,5m and finally, in the Beyler region, 0.5 m WorldView-2 and Spot-7 1.5 m satellite images were used. As a result of the classification made with Maximum Likelihood technique which is one of the controlled classification techniques, the total greenhouse assets calculated from the raster data were compared with the total greenhouse assets calculated from the data obtained by the terrestrial measurements, the accuracy of the study was calculated. Physiographic units and greenhouse production areas are respectively 126.19 ha in the Eskihisar region on alluvial land, 104.41 ha in Gölova-Çukurelma area, which contains very old lake base and alluvial fan, and finally, 38.23 ha in the Beyler area on the land of the basement. When the percentage increase in greenhouse activities is evaluated as time dependent, the highest increase is in Gölova-Çukurelma region (313.51%), second in Eskihisar region (166.27%) and the lowest increase in Beyler region (61.35%). When the accuracy rates of the study are examined, the highest accuracy of the year 2009 (94.83%) in the Eskihisar region, in 2016 (92.04%), Gölova-Çukurlema 2008 (89.33%), the lowest accuracy in 2016 (83.52%) in the Beyler region in 2011 (87.72%) in 2016 (83.95%).

The publication of Fenneman's two volumes on physiography: The Physiography of Western United States and the Physiography of Eastern United States, was the culmination of over 20 years of work toward formalization of the physiographic regions in the United States. This paper details the relevant works that predate these volumes, the two volumes themselves, as well as briefly describing Fenneman's career and the continued use of the works 80 plus years post-publication. [ABSTRACT FROM AUTHOR]

The transformation of rocks and organic inputs into parent material and soil is a dynamic process controlled by physical, chemical and biological factors. In this process, the parent material, climate, topography, organism and time are known as formation factors. The differences in physiography cause variability in soil properties with the effect of other formation factors. In this study; It is aimed to reveal how the physiographic variability is reflected in the profile morphology and the statistical effects of this reflection on soil properties. Morphological descriptions of four soil profiles (PI, PII, PIII, PIV) were made in the north-south direction to represent the varying physiographic units (shoulder, toeslope, backslope) and some physical and chemical properties of soil samples taken on the basis of the horizon were determined. In addition, the variables in soil properties were evaluated with some statistical parameters. As a result of the study, all profiles were classified as Lithic Xerorthent / Petrocalcic Leptosol. While the profiles on the upper and lower skirts have similar characteristics, it has been determined that the profile in the low plain differs in terms of horizon depth and thickness, soil color, lime content, texture and water characteristics. With this study, it has been revealed that the relationship can be explained more clearly as a result of the evaluation of the change in soil properties with statistical approaches. [ABSTRACT FROM AUTHOR]

Restoring degraded forest is essential if we are to reduce human pressure on natural ecosystems and their biodiversity. Forests were nationalized in 1957 in Nepal and as a consequence, forest cover declined from 45% in 1964 to just 29% in 1994. However, as its response, sectoral plans and policies, particularly introduction of community-based forest management programs since the 1980s and conservation activities resulted in large scale forest cover restoration. Here, we examined the forest cover change in the Gandaki River Basin (GRB), the catchment with the largest altitudinal variation (ranging from ± 93 to 8167 m) and environmental and ecological significance. To see how forests have changed since then, we analyzed snapshots of spatiotemporal, ecological and physiographic changes in forest cover, and forest type at decadal intervals from 1996 to 2016 using Landsat 5 and 8 satellite images. We observed an overall gain in forest cover of 207 km2, from 7571 km2 (34.4% of the total area) in 1996 to 7778 km2 (35.3%) in 2016. Of the 21 forest cover types identified, the greatest forest coverage during 2016 was of Schima-Castanopsis forest (25.9%) and hill sal forests (16.4%). In terms of physiographic zones, land below 500 m (Tarai) where most people live, witnessed gradual declines in forest cover, in contrast to large increases in forests above 500 m. Historical examination of forest cover at ecological and physiographic scales helps to identify the elevation-wise distribution of forest resources, vegetation composition, ecosystem characteristics, anthropogenic pressure upon vegetation, and hence the overall influence of LULC upon the environment. These outputs will assist planners, policy makers, and researchers in their formulation of effective basin wide plans and policies to ensure the protection of basin level biodiversity and ecosystem function. [ABSTRACT FROM AUTHOR]

A study was conducted in lower Shiwaliks of Punjab, India to study the soil organic carbon (SOC) stock variation in hill, piedmont plain and alluvial plain regions of Punjab, and further to investigate the SOC variability down the slope in the lower Shiwaliks region of Punjab. The SOC fractions viz. very labile carbon, labile carbon, less labile carbon and recalcitrant were determined using standard methodologies. The total SOC stock in 0–60 cm soil depth was highest in plain region (31.81 Mg ha−1), followed by piedmont (23.43 Mg ha−1) and lowest in hill region (22.86 Mg ha−1). Whereas, the SOC concentration in surface layer was highest in foot slope (5.76 g kg−1) followed by mid slope (4.14 g kg−1) and lowest in up slope (2.32 g kg−1). Among the SOC fractions the average labile carbon content in soil samples was found in the order, hills (0.81 g kg−1) > piedmonts (0.73 g kg−1) > plains (0.50 g kg−1). The soil bulk density (Db) was higher in the plain than that of piedmont and hills. Moreover, a similar trend is observed in case of water holding capacity. Regression analysis has revealed significant relationship between Db and SOC stock at p < 0.05. Further, analysis of variance (ANOVA) at p < 0.05 has indicated significant differences among concentration of SOC and stock influenced by land use and soil depths. Thus, an understanding of the effect of physiography on SOC via such studies is important for soil quality management. [ABSTRACT FROM AUTHOR]

Pedological surveys and physiographic characterization of a watershed are fundamental procedures for planning the soil use. Thus, the aim of this study was to characterize and map the soil classes of the Lajeado Pessegueiro watershed, located in Guarujá do Sul, Santa Catarina, Brazil. The types of land use and occupation, slope classes and physiography of the study area were delineated and described. Data were collected from 19 complete soil profiles and 9 extra samples. Physiographic analysis was performed using prior information on the photopedology of the terrain geomorphological characteristics, climatic conditions, vegetation, land use and geological conditions. The watershed has a predominant undulating relief (406.51 ha). The predominant land use is agricultural, with temporary annual crops (50.09%). The predominant physiography is colluvial erosional slope (35.53%), followed by erosional slope (27.13%), plateau slope (21.55%), alluvial colluvial valley bottom (10.51%) and erosional colluvial slope (5.23%). The soil classes found were Red Nitosols (37.54%), Haplic Nitosols (8.22%), Haplic Cambisols (35.20%), Fluvic Cambisols (3.92%), Red Argisols (10.09%) and Litholic Neosols (5.04%). The data showed the importance of using the physiographic analysis of the area with geoprocessing techniques, assisting pedological surveys with presentation through thematic maps. These maps serve as a base material in studies evaluating land uses, and those aiming to contribute to a better planning of soil use.