Soil morphology

Many Missouri forest soils exhibit fragipans, which influence soil productivity, ecosystem services and land management. Fragipan bearing soils tend to occur where loess thickness is moderate (1 to 2 meters) or where the soil profile exhibits evidence of mass wasting of weathered limestone residuum. Consensus is consolidating around the self-weight collapse of loess and residuum after repeated wetting and desiccation. The use of gravel as an indicator of parent material differences and its correlation with fragipan development is not perfectly aligned, thus although most fragipans do exhibit a bisequal soil profile, the placement of the lithologic discontinuity is difficult given mass wasting, eluviation-illuviation, side slopes, and other soil processes that contribute to increasing the bulk density and conferring strength. Fragipan genesis is evolving; however, research involving Ecosystem Site Descriptions are a fusion of a land parcel's soil properties, vegetational community, hydrology, and climate to guide land management. Ecological Site Descriptions associated with fragipan bearing soils are necessary, especially when making land management decisions.

This study clarifies the morphology, genesis, physico-chemical properties and classification of soils developed from volcanic parent materials of Mbeya Region, Tanzania. Six typical pedons (MWK 01, IFIG 02, MKY 03, MWZ 04, KYE 01 and NDE 01), were identified, described and 33 soil samples analyzed for physical and chemical characteristics. Results indicate that all pedons were very deep, with textures ranging between fine and coarse. Soil moisture retention ranged between low and medium (78 -101 mm/m). Some pedons had volcanic ash layers of varying thicknesses and buried 2BC, 2Bwb or 3Bwb horizons, typical of recent volcanic soils. Topsoils had low bulk and particle densities ranging between 0.70 to 1.26 g cm -3 and 1.95 to 2.55 g cm -3 , respectively. Organic carbon (OC) content ranged from medium to very high (1.29 to 5.58%). The studied pedons had extremely acidic to very slightly acidic pH ranging from 4.02 to 6.58. Cation exchange capacity (CEC) ranged from medium to very high (16.8 -41 cmol(+) kg -1 soil for topsoils and 21 -42.6 cmol(+) kg -1 for subsoils). All studied pedons had pH NaF > 9.5, reflecting an exchange complex dominated by amorphous Fe and Al oxides and/or humus complexes. Phosphate retention capacity (PRC) ranged from 25 to 97% and one pedon (MWZ 04) met the andic properties requirement of PRC ≥ 85%. SiO 2, Al 2 O 3 and Fe 2 O 3 ranged from 46.5 to 62.1%, 26.3 to 38.4% and 4.0 to 9.8%, respectively. On the basis of computed Chemical Index of Alteration (CIA), the degree of weathering of the studied pedons followed the trend NDE 01>MKY 03>MKW 01>KYE 01>IFIG 02>MWZ 04. According to USDA Soil Taxonomy, the studied pedons were classified as Alfisols (pedons MKW 01, MKY 03 and NDE 01), Inceptisol (pedon IFIG 02), Andisol (pedon MWZ 04) and Entisol (Pedon KYE 01), respectively correlating to Alisols, Cambisol, Andosol and Umbrisol of WRB for Soil Resources. The studied soils were generally rated as having low to medium fertility.

Soil horizons reflect soil processes and convey information about past and present soil conditions. The identification and delineation of soil horizons are affected by lateral and vertical variation in soil properties. Early studies focused on the variation of horizon thickness and the waviness of horizon boundaries, but did not consider within-horizon lateral and vertical variation. Here we review studies that investigated variation in the master horizons O, A, E, B, and C. We summarize what is known about soil horizon variation, quantify the variation in different horizons, and investigate whether the variation increases or decreases with depth. The variation within horizons differs among soils, and the magnitude of the variation varies for different soil properties. Variation within soil horizons or laterally within a few square meters may be considerable, and the within-horizon variation changes with depth. Horizon thickness does not seem to be related to the variation of soil chemical and physical properties within the horizon, i.e., thicker horizons do not necessarily have higher variation in their soil properties. Three case studies are presented: Spodosols and Histosols (Russia), Alfisol and Mollisol (USA), and Oxisol (Brazil). Factors that affect the within-horizon variations include landscape position, parent material, vegetation, fertilization, tillage, drainage, and time. The vertical distribution of soil properties can be quantified using soil depth functions. Digital soil morphometrics techniques can assist in the quantification of two-dimensional soil profile properties and variations.

The open pit minning process has an impact on soil properties, including the soil physical properties. The physical properties of soil in the rehabilitation area will develops over time. This study purpose was to determine the soil physical properties development in the 20 years old rehabilitation area and compare it with the forest area. Soil samples test was carried out in the laboratory, data analysis refers to the criteria for assessing the soil physical properties. Based on the soil profiles observations it is known that the rehabilitation area has 3 horizon, horizon boundaries are clear; 72 cm root depth; soil consistency and soil structure varies, soil texture is the silty clay loam. Theforest area has 6 horizon, horizon boundaries are diffuse, 117 cm roots depth; soil consistency is predominantly firm (moist conditions) and sticky to very sticky (wet conditions); soil structures is sub-angular bocky and angular blocky, soil texture is sandy loam. The value of soil permeabili...

Background: Soil carbon stocks (SCS) play a key role in regulating soil fertility and global climate. Determining the amount of SCS through a pedological approach is still limited, while the amount of SCS in highland areas based on elevation is still debated, also the role of elevation-slope combinations on SCS is not well known. This research aims to determine the amount of SCS in each soil horizon, elevation, slope position and also the effect of elevation and slope position on SCS. Methods: A total of 46 undisturbed and disturbed soil samples were collected in each pedogenic horizon from 12 soil profiles at four elevation levels ie 700-715; 1000-1060; 1300-1351; 1600-1616 meter above sea levael (m.a.s.l.) and three slope positions (foot, middle, and upper of slope) in Gayo highland Arabica coffee plantation fields. Result: The results showed that SCS of soil horizons in Arabica coffee plantations in the Gayo highlands varied from 5.97 to 84.56 MgC.ha-1 , with SCS of the upper horizons being higher than those of the lower horizons. The amount of solum SCS from the soil profile also varied from 73.91 to 218.25 MgC.ha-1. Based on the elevation, the highest mean amount of SCS of the solum was 157.35 MgC.ha-1 which was found at the elevation of 1600-1616 m.a.s.l, whereas the mean amount of solum according to the slope position was 167.34 MgC.ha-1 which was found on the foot of slope. Elevation and slope position significantly increased the SCS with the highest value found in the combination of 1000-1060 m.a.s.l, and foot of slope.

The study was conducted in three selected sites representing the soils of three governorates of central and northern Iraq (Salah al-Din, Kirkuk, and Erbil), to determine the effect of morphological, physical and chemical characteristics of some soil genetic horizons on their spectral reflectivity using digital camera as well as Knowing the degree of soil development and classification according to the Quantitative (American) system for classifying soils, Three pedons representing these soils were excavated, the horizons were morphologically diagnosed and samples were obtained from each horizon of each pedon from the soils of the study sites to conduct some laboratory tests for the physical and chemical properties. Pictures were taken that combine dry and wet samples; In order to calculate the spectral reflectivity and RGB values using ERDAS software. The results revealed a heterogeneity in the morphological characteristics represented by the dominant color class of each pedon, with ...

The countries of the European Union have joined, inter alia, soil protection in the Common Agricultural Policy (hereinafter referred to as CAP). Accelerated soil erosion is a problem resulting from inappropriate land management, which affects both the presence of organic matter and the soil structure. The tool for elimination of negative impacts on soil can be its sustainable use. This requires the use of an accurate system to improve its condition. The first step should be problem identification and localisation. The research is aimed at the identification of water erosion risk areas by using selected methodological procedures. The research area was located at the intensively used hilly land of the Southwestern Slovakia. The digitisation of the manual interpretation of erosion risk areas with the use of aerial photos, erosion modelling, chemical analysis of soil organic matter (SOM) and analysis of soil structure were used. Verification was implemented via the field research with the use of the soil probes. Methods affirmed significant presence of the water erosion in the area. Efficient identification of erosional processes is possible via combination of presented methods by taking into consideration geological, geomorphological, pedological and geographical conditions and the use of the area over a longer period of time. The results of using methods that ensure accurate and effective localisation of erosion surfaces can be used for sustainable land use and its conservation.

Currently, soil characterization and classification are becoming the primary source of information for precision agriculture, land use planning, and management. Thus, this study was focused on perusing the landscape-scale spatial variation of soils in data-scarce areas using toposequence-based ground sampling to characterize and classify the soils. Six typical profiles representing major landforms were opened and studied for their morphological characteristics and physical and chemical properties. Results revealed that the soils were shallow to very deep in depth, moderately acidic to moderately alkaline in soil reaction, non-saline in salinity, and clay to sandy loam in texture. The soils were found to be very low to low in organic carbon, very low to medium in TN, low to medium in av. P, very low in av. S, very low to low in av. B, high to very high in CEC and very low to very high in base saturation. The soils were also found deficient in Zn and sufficient in Fe, Cu, and Mn. Foll...

Land use capability class (LUCC) is of great importance in guiding on land uses in terms of their potential and conserving natural resources for next generations. The concept of land capability is useful in this respect because it is a composite assessment of land and soil, which incorporates the key physical characteristics that limit sustainable land management. Such an approach is simple and logical in approach, is widely known and accepted in the rural community and has been applied widely. LUCC system the range of suited crops decreased from class 1 to 8 and the management inputs required to produce suited crops increases from class 1 to class 8. However, the combination of soils, climate and types of agriculture in a particular area or region may make certain lower capability lands valuable for agriculture. Join analysis of LUCC with topography offers a precious tool to agricultural practices and land use planners revealing the most suitable land for agricultural aims both from LUCC and physiographic point of view. The main objective of this study was to determine relationship LUCC and land forms using GIS in Bafra Plain and near district found in the Kızılırmak Delta and located in the central Black Sea region of Turkey. The study area covers about 77796.1 ha. In this study, LUCC information derived from soil database prepared by the Rural Affairs General Directory and topographic maps scaled 1:25.000 to generate digital elevation model (DEM) were used. According to LUCC distribution of the study area, suitable land for agricultural application ranged from class 1 to class 4 is 53244.4 ha whereas, 24551.7 ha of the total area is non suitable (from class 5 to 8) for tillage. Land slope, aspect, hill shade, drainage network, creation of a three dimensional network structure of earth surface are among application of DEM. In finally, LUCC map painted in various colors was combined by the hill-shade image to generate three dimensional view images.

The name of Vertisol is derived from Latin “vertere” meaning to invert, thus limiting the development of classical soil horizons. These soils have the capacity to swell and shrink, inducing cracks in the upper parts of the soil and distinctive soil structure throughout the soil. The formation of these specific features are caused by a heavy texture, a dominance of swelling clay in the fine fraction and marked changes in moisture content. The swell-shrink behavior is attributed to the wetting and drying of the soil mass. In this study, morphology, physico-chemical characteristics and classification of two vertisols that were formed on alluvial delta plains, were investigated. The first one has been formed on the Bafra Plain found in the Kizilirmak Delta and located in the central Black Sea region of Turkey. The soil is very deep, color ranges from dark olive brown to very dark grayish brown (in dry and wet conditions) and clay content is between 53-63 % within the one meter. The seco...

explain (i) the physical processes involved in fragipan genesis, such as self-weight collapse followed by physical The evolution of fragipans in the Great Lakes region is poorly ripening (Bryant, 1989), or (ii) the physical and chemical understood despite the common occurrence of fragipans in the region. To help resolve this problem, three soils with fragipans in northern processes involved in fragipan bonding by agents, such Michigan were studied to evaluate the pedogenic pathways for fragi-as translocated silica or Si-rich pan evolution, and the results extended to soils forming under similar aluminosilicates (Karathanasis, 1989) or precipitation conditions. Soil characterizations were made via field, physical, chemiof acid-weathering products (Smeck et al., 1989), or (iii) cal, and micromorphological observations and analyses and were evalboth . Formation and development uated in terms of the major models of fragipan genesis. Because it of these binding agents have been proposed to occur in appears that a combination of pedogenic models best explains many association with lithologic, hydrologic, or weathering of the fragipan properties of our soils, while also allowing for their discontinuities in the solum Kara-variable expression, we developed a new model-one that integrates thanasis, 1989; Smeck et al., 1989). The purpose of this study was to (i) identify and evolution for many soils in Michigan and the Great Lakes region. The Michigan Model of Fragipan Evolution (MMFE) is therefore a describe pedogenic processes important to fragipan evosynthesizing model that involves the self-weight collapse of a wet soil lution based on some Michigan soils, formed in till, that or parent material, followed by physical ripening of the collapsed have variable fragipan expression, (ii) infer fragipan zone. Ripening helps to retain the closely packed fabric and intergrain genesis based on data from these soils, linked to existing bridging in the collapsed zone, creating a protofragipan. Later, amorpedogenic models, and (iii) evaluate our findings in phous bonding agents precipitate in the protofragipan due to its positerms of these models so as to develop a new, synthesiztion near a weathering-front discontinuity. The resulting fragipan deing, and integrating model of fragipan evolution. Alvelops progressively and becomes better expressed with further though developed from and for Michigan soils, our pedogenesis. Fragipan degradation is eventually initiated by an inmodel may have, theoretically, wide applicability. creasingly prominent, perched zone of saturation that forms seasonally above the fragipan. With time, processes associated with fragipan degradation and translocation of materials to lower parts of the profile MATERIALS AND METHODS exceed processes associated with progressive development, and the Soil series from across northern Michigan that exhibit varifragipan is destroyed. able degrees of fragipan expression were studied. The Feldhauser (coarse-loamy, mixed, active, frigid Oxyaquic Glossudalfs), Munising (coarse-loamy, mixed, active, frigid Alfic M ost papers on fragipan genesis have focused on Oxyaquic Fragiorthods), and Glennie (coarse-loamy, mixed, superactive, frigid Oxyaquic Fraglossudalfs) soil series repre-loess parent materials of the southcentral and sent weakly, moderately, and strongly expressed fragipans, midwestern USA. Fragipan research, particularly gerespectively, relative to other soils with fragipans in the region. netic studies, has been less active elsewhere. During the A study location for each series was selected based on site past two decades, only a few have discussed fragipan similarities, and the soils were sampled from a backhoe pit. genesis for the Great Lakes region (e.g., Habecker et Details on field and laboratory analyses are provided else- al., 1990; Miller et al., 1993; Bockheim, 2003). Fragipans where . Sodium citrate-dithiin Michigan, more specifically, have been studied very onite was used to extract Fe, Al, and SiO 2 on the Ͻ2 mm little since Yassoglou and Whiteside (1960), despite fraction of all genetic horizons (Ross and Wang, 1993; Loeptheir common occurrence across northern Michigan. pert and Inskeep, 1996); results are written with a sub-Moreover, they have not been evaluated in terms of the scripted d. Undisturbed, bulk samples were collected from all proto-major genetic models developed for glaciated regions fragipan and fragipan horizons for micromorphological deduring the past four decades (e.g., Olson and Hole, 1967; scription using scanning electron microscopy (scanning elec-

The scientific study of the soil started almost 70-80 years ago with two school of thoughts, one worked in the lab and others in field. The main aim of the researchers studying in the field was to determine the profiles of soil along with its horizons so as to extent the knowledge on physical, chemical and biological properties. The distinctness of soil with depth means that soil has unique profile. All the soils in the world has some specific depth functions. The change of soil color or soil texture in a soil profile can be considered a good indicator of the soil formation and process and has been used as a proxy for degree of development or soil age. Uniform, gradational and rapidly changing soil textures are examples of soil profile forms used for soil classification. In the current study we studied twelve profiles having four different land uses and observed several horizons having various boundaries. The upper horizons were having diffused and wavy boundaries than the lower hor...

The soils on Imo Clay Shale residua were sampled at Anaku and Igbariam in Anambra state, Nigeria to characterize, classify and evaluate their current suitability for rice production following standard scientific procedures. After several auger borings, modal profiles were sited, dug, described, and sampled. The soils generally belong to loamy textural classes or finer, especially in the subsoil layers. The morphological and physical properties of soils showed that the soils were poorly drained, favouring high water retention due to low hydraulic conductivity and slow permeability. All these conditions favour good rice performance. Though the soils contained high levels of exchangeable bases, exchangeable acidity was equally high leading to low base saturation (< 35%). Thus, the soils were classified as Typic Kanhaplaquults (Soil Taxonomy) and correlated to Gleyic Cambisols (World Reference Base for Soil Resources). Due to fertility inadequacies, the current suitability unit of the soils for rice production is S2f. This implies that for sustainable rice production supplementary nutrient especially P2O5 from triple superphosphate or rock phosphate need to be applied. Based on the soil chemical results the following recommendations were made for optimum rice production: 100.00-120.00 kg ha-1 urea, 60.00 kg ha-1 P2O5 from triple superphosphate and 15.00 kg ha-1 K2O (muriate of potash).

Purpose Land preparation (e.g., leveled ditches, leveled benches, adversely graded tableland, and fish-scale pits) is one of the most effective ecological engineering practices to reduce water erosion in the Loess Plateau, China. Land preparation greatly affects soil physicochemical properties. This study investigated the influence of different land preparation techniques during vegetation restoration on soil conditions, which remained poorly understood to date. Materials and methods Soil samples were collected from depths of 0-10, 10-20, 20-40, 40-60, 60-80, and 80-100 cm, in the typical hilly watershed of Dingxi City, Loess Plateau. Soil bulk density (BD), soil organic matter (SOM), and total nitrogen (TN) were determined for different land preparations and vegetation type combinations. Fractal theory was used to analyze soil particle size distribution (PSD). Results and discussion (1) The effect of land preparation on soil properties and PSD varied with soil depth. For each land preparation category, SOM and TN values showed a significant difference between the top soil layer and the underlying soil depths. (2) The fractal dimension of PSD showed a significant positive correlation with clay and silt content, but a significant negative correlation with sand content. (3) The 20 cm soil layer was a boundary that distinguished the explanatory factors, with land preparation and vegetation type as the controlling factors in the 0-20-and 20-100-cm soil layers, respectively. Conclusions Land preparation and vegetation type significantly influenced soil properties, with 20 cm soil depth being the boundary for these two factors. This study provided a foundation for developing techniques for vegetation restoration in water-limited ecosystems.

The name of Vertisol is derived from Latin "vertere" meaning to invert, thus limiting the development of classical soil horizons. These soils have the capacity to swell and shrink, inducing cracks in the upper parts of the soil and distinctive soil structure throughout the soil. The formation of these specific features are caused by a heavy texture, a dominance of swelling clay in the fine fraction and marked changes in moisture content. The swell-shrink behavior is attributed to the wetting and drying of the soil mass. In this study, morphology, physico-chemical characteristics and classification of two vertisols that were formed on alluvial delta plains, were investigated. The first one has been formed on the Bafra Plain found in the Kızılırmak Delta and located in the central Black Sea region of Turkey. The soil is very deep, color ranges from dark olive brown to very dark grayish brown (in dry and wet conditions) and clay content is between 53-63 % within the one meter. The second pedon has been formed on the Çarşamba Plain found in the Yeşilırmak Delta and located in the central Black Sea region of Turkey. This pedon has also more than one meter depth, clay content changes between 53-56 %. However, this pedon has lighter color than other one. Slickensides, clay cutans and crack of 3-5 cm wide extends beyond one meter were observed in both pedons. According to Soil Taxonomy and FAO-Unesco Soil Map of the World Legend classification systems, the pedon formed on Bafra delta plain was classified as Chromic Endoaquert sub group and Chromic Vertisol soil unit while, the other pedon formed on Çarşmaba delta plain was classified as Typic Haplustert sub groups and as Eutric Vertisol soil unit, respectively.

Measuring soil water-physical properties is laborious, time-consuming, and expensive. That provokes a lot of scientists to estimate them which action is troubled by the usage of different soil texture classification systems. The study proposes a rapid, reliable, and universally applicable methodology for soil textural transformations between different classification systems. The method of discrete mathematics is applied to make the conversion of particlesize classes from the Kachinsky system, which is used in Bulgaria to the International systems. Three different data sources were used to determine the water-physical properties of soils from textural data -376 soil profiles from Bulgaria, extraction from the SoilGrids system for the Plovdiv district in Bulgaria and data from CanSIS/NSDB database. The relationship between the dependent variables field capacity (FC), wilting point (WP) and bulk density (BD), and independent variables sand, silt, and clay soil content was sought in the form of a regression equation. The applied stepwise regression procedure produces a close dependence between the soil texture and its water-physical properties.

Biogeochemical and hydrological cycles are currently studied on a small experimental forested watershed (4.5 km²) in the semi-humid South India. This paper presents one of the first data referring to the distribution and dynamics of a widespread red soil (Ferralsols and Chromic Luvisols) and black soil (Vertisols and Vertic intergrades) cover, and its possible relationship with the recent development of the erosion process. The soil map was established from the observation of isolated soil profiles and toposequences, and surveys of soil electromagnetic conductivity (EM31, Geonics

This study examines the role of abiotic (texture, calcium carbonates or iron) and biotic parameters (earthworm and enchytraeid activities) on the initial phases of soil aggregation. Our research focused on humus forms in alluvial soils, which are considered as young and heterogeneous environments. We hypothesized that the soil structure formation is determined by both the nature of the recent alluvial deposits and the soil fauna. For this purpose, six sites were chosen throughout two types of softwood forests (willow and alder forest) representing two stages of vegetation succession. Evidence of soil texture influence on aggregate stability was observed. A dominance of a coarse sand fraction caused a quick colonization of enchytraeids and epigeic earthworms while a silty texture favoured the presence of anecic earthworms, thus increasing the aggregate stabilisation. Iron forms, acting as cementing agents, were observed in the coarse silt, while calcium carbonates were equally distributed among the textural fractions. Active calcium carbonate fraction, binding organic matter with mineral components, was not found in the coarse sand fraction. In conclusion, the tree age cannot alone be used as an indicator of the humus form evolution but biological and physicochemical parameters also influence the initial steps of soil structuration.

The objective of this study was to determine direct and indirect effects of some soil properties on soil penetration resistance. The experimental field was gridded with 80 m intervals in the E-W and N-S directions, and soil penetration resistance was measured at 72 intersections using a penetrologger. Soil samples from upper and lower soil layers were also taken at the same points for determining physical and chemical soil properties. The results of study indicated that the highest direct effect to upper soil layer compaction was sand, silt and clay content and the lowest was bulk density. On the other hand, the highest direct effect to subsoil layer compaction was bulk density and lowest was clay content.

Based on field soil-ameliorative and laboratory-analytical studies, the main properties and ameliorative state of the soils of the foothill plain of the Mirzachol Steppe have been studied, within the territory of the Djizak steppe. The characteristic of the modern salt accumulation is given in connection with the development of irrigation of the territory, as well as the peculiarities of the manifestation of secondary salinization on irrigated lands.

The most potential soil order in Indonesia is dominated by Inceptisols, whereas the topography combined with a climatic factor are the main factors to regulate pedogenetic process. This research was intended to determine the pedogenetic process and soil development on various terrain positions at the southeast toposequence of Mount Manglayang areas that have hilly topography. The researched area was 28.83 ha. Based on those conditions, this research aims to study the pedogenetic process and soil development in the southeast slope toposequence of Mount Manglayang, the relationship between the physical, chemical, and mineralogical soil properties, the soil classification to family level based on soil taxonomy, National Soil Classification, and FAO soil classification systems. This research used survey, descriptive, and comparative methods. The result showed that the pedogenetic processes identified were the formation of B horizon through clay accumulation, soil colour, and soil structure development, and the formation of amorphous kaolinite and halloysite minerals. Based on soil taxonomy, the soil were classified as Fluventic Humudepts, coarse-loamy, kaolinitic, isohyperthermic at the upper slope and Fluventic Dystrudepts, fineloamy, kaolinitic, isohyperthermic at the middle and lower slopes. According to National Soil Classification, the soil is Humic Cambisol at the upper slope, Distric Cambisol at the middle slope, and Cromic Cambisol at the lower slope. FAO classified the soil as Umbric Cambisols at the upper slope and Dystric Cambisols at the middle and lower slopes.

The scarcity of comprehensive characterizations of soils associated to gentle summit depressions of the Northeastern Brazilian Coastal Plains justifies this work, which had as objective to provide basic information for the more diverse agricultural and non-agricultural uses. For that, representative soils (Spodosols or similar soils) from these environments were selected in Alagoas, Sergipe and Bahia states. This approach included characterization of morphological, mineralogical and micromorphological properties of the soil profiles, employing standard procedures. The morphological characterization corroborated the effect of the podzolization process during the formation of these soils. The mineralogy of the clay fraction of these soils was basically composed of kaolinite and quartz, which, associated to the very sandy texture, helped in the understanding of the obtained data. The soil micromorphological study, besides confirming the field morphology, mainly in regard to the strong cementation, aggregated value to the work in terms of the secure identification of the clay illuviation process (non-identified in the field), in association with the dominant podzolization process.

The New Bedford Harbor Superfund Site in southeastern Massachusetts includes the shallow northern reaches of the Acushnet River estuary through the commercial port of New Bedford and adjacent areas of Buzzards Bay. The sediments in the harbor are contaminated with high levels of polychlorinated biphenyls (PCBs) and heavy metals from the industrial development surrounding the harbor. From the 1940s through the 1970s, electrical capacitor manufacturing plants discharged PCBs into New Bedford Harbor and its estuaries. In the mid-1970s US Environmental Protection Agency (EPA) sampling identified PCBs in the river and harbor sediments greater than 100,000 mg/kg. In 1979, the Massachusetts Department of Public Health prohibited fishing and shell-fishing from the river and harbor due to the high levels of PCB contamination found in the harbor and in the seafood from the area. The site was included on the National Priorities List (NPL) in September 1983 as one of the most contaminated PCB sites in the United States. In September 1998, after years of study and public debate, EPA selected a cleanup remedy that involved the dredging and containment of approximately 170 acres of PCB-contaminated sediment. The principal goals of the project were the reduction in health risks from consumption of PCB-contaminated local seafood and from exposure to contaminated shoreline sediments, and the improvement of water quality in the marine ecosystem.

Understanding of soil forming factors is crucial to define physical, mineralogical and morphological properties of soils. In addition to that soil formations were highly associated with slope positions which have influence on pedogenetic and weathering process of the soils. Because, topography or relief affects how water and other material are added to and removed from soils. The aim of this study is to enhance our understanding of the role toposequence in controlling chemical weathering, influence on physical and mineralogical properties in soils developed on basaltic parent material under sub-humid terrestrial ecosystem in Black Sea region of Turkey using geochemical and mineralogical data obtained from X-ray diffraction and Scanning Electron Microscope analysis. For this purpose, four representative profiles formed on different topographic positions of transect were investigated and designated according to Soil Survey Staff (2014)/IUSS Working Group WRB (2015) classification systems. The results clearly showed that topography strongly affects soil physical, mineralogical and morphological characteristics either directly or indirectly in the local region even soils formed on the same parent material with the same climatic condition. This case was also explained with chemical weathering indices (Chemical Index of Alteration and Chemical Index of Weathering) in this study.

As Thesis research advisors, we hereby Certify that we have read and evaluated the Thesis entitled "Assessment of Soil Physicochemical Properties along the Toposequence at Golina Afar Region Ethiopia prepared under our guidance by Mohammed Musa. We recommend that it be submitted as fulfilling the thesis requirement of the Natural Resource Management Department for defense.

Paleosols can widely be used as chronometric markers, and the so-called Finow soil is reported to be a supraregional marker in the sandy deposits in northern central Europe and Siberia. The Finow soil is thought to be associated with pedogenesis between the Allerød and the Younger Dryas with subsequent fossilization by eolian activity. The formation of the 5-to 15-cm-thick brownish Finow soils is often explained by brunification and some minor illuviation of clay. Although the Finow soil has been described at several distant sites, the lack of an entire soil sequence consisting of a topsoil and a subsoil recently raised doubts about the formation of the Finow soil. We present a micromorphological approach together with grain size analysis from two sites in northeastern Germany (Glashütte and Jänschwalde in Brandenburg) and one site in Poland (Błędno) where purported Finow soils have been reported and were dated in earlier studies to investigate the processes that led to the formation of the Finow soil. Our findings show that the three studied Finow soils are characterized by clay migration, rather than brunification, and that the Finow soils are situated below well-drained sandy deposits at hydrological barriers. Whereas at Glashütte, the soil organic matter of an Usselo soil acts as a hydrological barrier, at Jänschwalde and Błędno, changes in the granulometry of the sandy deposits presumably act as a hydrological barrier. At Jänschwalde, the illuvial horizon is the least developed of the three sites and the eluvial horizon has a depth of only 40 cm, but at Glashütte, the Finow soil below the 330-cm-thick sandy deposit shows extensive features of clay illuviation. Hence, we propose that the thickness of the eluvial horizon strongly influences the degree of clay illuviation in the Finow soil. Further, we propose that due to the well-drained character of the sandy substrates, the formation of the Finow soil is limited to the supply of clay for the clay migration rather than being time limited. Therefore, the clay illuvial features of the Finow soil are indicative of neither the suggested pre-Holocene soil development nor of the lack of the eluvial and topsoil horizons of the supposedly truncated Finow soil due to late Quaternary soil erosion or landscape activity. Indeed, the clay illuviation that causes the formation of the Finow soil can visually accentuate sedimentological changes, but because the clay illuviation is a postsedimentary process, the indicative potential of the Finow soil is site specific. Hence, we conclude that the use of the Finow soil as a supraregional chronometric or pedostratigraphic marker should be avoided.

This study was carried out in Kilombero District, Tanzania with the objective of characterizing the soils in terms of their morphology, genesis, physico-chemical properties and classification. Three pedons KISA-P1, MKU-P1 and MBA-P1 were identified within the Kilombero Valley, dug, described and sampled. Disturbed and undisturbed soil samples were taken from designated pedogenic horizons for physical and chemical analysis in the laboratory. Using both field and laboratory data soils were classified using both USDA Soil Taxonomy and World Reference Base for Soil Resources schemes of classification. Results show that the three pedons were developed under Isohyperthemic temperature and Aquic moisture regimes. All pedons were deep (100-120 cm). Whereas Pedons KISA-P1 and MBA-P1 had sandy clay loam topsoils overlying sandy clay subsoils, Pedon MKU-P1 had clayey texture throughout its profile depth. All pedons had low chromas of ≤ 3 and redoximorphic features in form of abundant mottles particularly in the subsoils. Topsoils of Pedons KISA-P1 and MBA-P1 had dominantly friable to very friable moist consistence while those of Pedon MKU-P1 had very firm moist consistence. Subsoil moist consistence varied from firm to extremely firm (Pedons KISA-P1 and MKU-P1) and from friable to very firm (Pedon MBA-P1). Structures were dominantly weak to moderate subangular blocky in all studied soils but some horizons were structureless single grained and massive. Soil reaction ranged from extremely acid (topsoil of MBA-P1) to mildly alkaline (subsoil of MKU-P1) with pH values of 4.44 and 6.73 respectively. Topsoil organic carbon and total nitrogen contents in the studied pedons were low (0.66 to 1.4%) and very low to low (0.08 to 0.19%) respectively. CEC soil values were rated as low to medium ranging from 8.4 to 23.8 cmol (+)/kg respectively in Pedon KISA-P1 and Pedon MKU-P1. Percent BS values varied between and within studied pedons and ranged from low < 50% to high > 50%. Studied soils manifested nutrient imbalances in respect of basic cations. On the overall, fertility of the studied soils was rated as low to medium. According to USDA Keys to Soil Taxonomy, Pedons KISA-P1 and MKU-P1 classified as Inceptisols, equivalent to Cambisols in WRB for Soil Resources whereas Pedon MBA-P1 classified as Entisols equivalent to Fluvisols. All three sites were recommended for paddy production.

Soil classification is a useful tool for understanding and managing soils. Latest editions of Soil Taxonomy (2014) and WRB (2015) were compared for classification of calcareous and gypsiferous soils of southern Kerman in the present research. Soils along Jiroft-Kahnooj transect with ustic and hyperthermic moisture and temperature regimes were selected. Eleven pedons were described and sampled. Routine physical and chemical analyses were performed and soils were classified according to Soil Taxonomy (2014) and WRB (2015) systems. Calcic, gypsic, anhydritic, salic, argillic (argic), and cambic diagnostic horizons were investigated after field and laboratory work. Based on the findings of the research, it is recommended that new Calciustalfs and Saliustepts great groups and Salic Anhydritic Calciustepts, Salic Calciustepts, Anhydritic Calciustepts, and Anhydritic Saliustepts subgroups are added to Soil Taxonomy (2014) classification system. Anhydritic diagnostic horizon, property, or material and paralithic qualifier were also suggested for WRB (2015) classification system. Calcium carbonate equivalent percentage needed for calcic horizon in WRB (2015) system is suggested to be redefined as the 2.c required characteristics of calcic horizon in Soil Taxonomy (2014) system. Results of the study showed that WRB (2015) classification system using various qualifiers and specifiers could classify soils of the area, especially saline soils, more efficiently than Soil Taxonomy.

Dynamics and distribution of soil characteristics as influenced by landscape /topographic features in acidic soils of Tsegede area in Northern Ethiopia has limited information. This study was conducted to characterize soil properties and classify major soil types. Four representative profiles along top sequence from varying slope positions crest at (Chegarkudo), upper slope and middle slope at (Endassilassie) and lower slope at (Intabela) were opened and described in-situ for morphological properties of soils and sampled horizon-wise for physico-chemical soil properties’ analysis. The results showed that soils at crest and upper-slope position were characterized by shallow depth, whereas those at middle and lower-slope positions exhibited relatively deep. The soil consistence ranges from slightly hard to hard (dry), friable to very friable (moist), yellowish red to dark red brown (dry) in color, moderate medium sub-angular to strong thick angular blocky in structure. The pH of surface soil ranged from 5.14 to 5.74 which was strongly acidic to slightly acidic and varied from clay loam to clay in texture, organic carbon, exchangeable bases and cation exchange capacity varied with profile depth. Based on the world reference base legend, the soils were classified as Skeletic Leptosols about 3756 ha, Cambic Leptosols about 1926 ha, Dystric Cambisols about 1883 ha and Leptic Cambisols about 1966 ha.

The soil cover of the forest-steppe and steppe zones of the East European Plain is characterized by diverse soil combinations revealed during large-scale and detailed soil mapping against the background of a traditional zonal sequence of dominant automorphic soils alternating from the north to the south and clearly displayed on small-scale soil maps. The composition, configuration and functioning of particular soil cover patterns are determined by the soil forming factors acting within a given area. The elementary soil areas (detailed scale) and elementary soil cover patterns maps (large scale) of the Central Russian, Kalach, and Volga Uplands are created by both traditional and digital soil mapping methods. Low-contrasting soil combinations with the background Haplic Chernozems (Loamic or Clayic, Pachic) alternating with zooturbated Haplic Chernozems (Loamic or Clayic, Pachic) on convex elements of the microtopography and Luvic Chernozems (Loamic or Clayic, Pachic) on concave eleme...

une grande hétérogénéité de la stabilité structurale entre les différents sites alors que ces derniers présentaient le même type de sol. Le MWD de la croûte variait entre 0,33 et 2,04 mm tandis que le MWD de la sous-croûte variait entre 0,23 et 1,42 mm. La texture du sol et le pH étaient très homogènes entre les sites étudiés, tandis que la teneur en eau, la teneur en matière organique et la CEC variaient plus fortement. Bien que certaines corrélations aient été identifiées (par exemple r=0.57 entre le MWD du test à l'humectation lente et la teneur en carbone organique), aucune de ces propriétés n'a permis de prédire précisément la stabilité structurale. La stabilité structurale de la croûte était significativement supérieure à celle de la sous-croûte. Les grandes différences de stabilité structurale mesurées impliquent des érodabilités très contrastées. Comme un seul type de sol a été étudié, ce résultat prouve que l'érodabilité peut être très variable spatialement pour un type de sol donné. L'érodabilité inter-rigole du sol devrait être mesurée sur le matériau exact qui subit l'érosion, c'est-à-dire le matériau de surface. L'utilisation du matériau sous-jacent aurait engendré une forte surestimation de l'érodabilité et donc un biais important dans les prédictions d'un modèle d'érosion.

une grande hétérogénéité de la stabilité structurale entre les différents sites alors que ces derniers présentaient le même type de sol. Le MWD de la croûte variait entre 0,33 et 2,04 mm tandis que le MWD de la sous-croûte variait entre 0,23 et 1,42 mm. La texture du sol et le pH étaient très homogènes entre les sites étudiés, tandis que la teneur en eau, la teneur en matière organique et la CEC variaient plus fortement. Bien que certaines corrélations aient été identifiées (par exemple r=0.57 entre le MWD du test à l'humectation lente et la teneur en carbone organique), aucune de ces propriétés n'a permis de prédire précisément la stabilité structurale. La stabilité structurale de la croûte était significativement supérieure à celle de la sous-croûte. Les grandes différences de stabilité structurale mesurées impliquent des érodabilités très contrastées. Comme un seul type de sol a été étudié, ce résultat prouve que l'érodabilité peut être très variable spatialement pour un type de sol donné. L'érodabilité inter-rigole du sol devrait être mesurée sur le matériau exact qui subit l'érosion, c'est-à-dire le matériau de surface. L'utilisation du matériau sous-jacent aurait engendré une forte surestimation de l'érodabilité et donc un biais important dans les prédictions d'un modèle d'érosion.

The structural mountain range of Baturagung continue to undergo soil development, influenced by various factors, including landform, geomorphological processes, and land use management. This research is grounded in the potential of soil resources based on landform, demanding precise land management and conservation. The study involved transecting and soil sampling across different landform features in the eastern part of Parangtritis Village. The delineation of these features was aided by the modification of the topographic position index-based landform classification. Research data revealed that the landform types encompass shoulders, backslopes, footslopes, toeslopes, depressions, and floodplains. Each of these landform features exhibits distinct soil characteristics concerning depth, color, texture, and mottling, as well as organic matter, manganese, and carbonate content. These characteristics also represent soil problems that require special management, including shallow soils, steep soils, Vertisols, and anthropogenic soils experiencing compaction. Proper soil management is essential to mitigate land degradation. Therefore, investigating the variations in soil characteristics based on geomorphology is crucial for comprehending their formation and development processes and for factoring them into land management decisions.

This study was conducted to characterize dominant soil type at Dakawa Irrigation Scheme (DIS), Tanzania. Typical soil at DIS was identified, excavated and described using Guidelines. Six disturbed samples were taken from soil profile horizons together with three undisturbed core samples for laboratory analysis. The pedon developed from Neogene alluvial parent materials under ustic moisture and isohyperthermic temperature regimes. The pedon was very deep (> 150 cm), moderately well drained, with gray to very dark gray soil colours. CaCO 3 concretions characteristic of calcic horizon were observed in subsoil. Soil texture was sandy clay loam throughout the pedon. pH was rated as medium (5.5 -7.0) to very high (7.0 -8.5) respectively for topsoil and subsoil. OC and N levels were very low; CEC and exchangeable bases were low to medium. Bulk densities were high (1.8 gcm -3 ) to very high (>1.9 gcm -3 ) for topsoil and subsoil, respectively. Study on moisture retention properties showed that subsurface (95 -100 cm) and intermediate (45 -50 cm) horizons retained more water than surface (0 -5 cm) soil, congruent with increasing clay content with depth. According to Soil Taxonomy and World Reference Base for Soil Resources, pedon at DIS classified as Vertic Calciustepts and Haplic Vertic Cambisols, respectively. These taxa reflect properties that may guide use and management of soils at DIS including selection of crops and fertilizers and rates to use. Organic fertilizers were recommended to increase organic matter content in soil. Use of acidifying inorganic fertilizers and gypsum as soil amendments should also be taken onboard to correct emerging sodicity.

This study clarifies the morphology, genesis, physico-chemical properties and classification of soils developed from volcanic parent materials of Mbeya Region, Tanzania. Six typical pedons (MWK 01, IFIG 02, MKY 03, MWZ 04, KYE 01 and NDE 01), were identified, described and 33 soil samples analyzed for physical and chemical characteristics. Results indicate that all pedons were very deep, with textures ranging between fine and coarse. Soil moisture retention ranged between low and medium (78 -101 mm/m). Some pedons had volcanic ash layers of varying thicknesses and buried 2BC, 2Bwb or 3Bwb horizons, typical of recent volcanic soils. Topsoils had low bulk and particle densities ranging between 0.70 to 1.26 g cm -3 and 1.95 to 2.55 g cm -3 , respectively. Organic carbon (OC) content ranged from medium to very high (1.29 to 5.58%). The studied pedons had extremely acidic to very slightly acidic pH ranging from 4.02 to 6.58. Cation exchange capacity (CEC) ranged from medium to very high (16.8 -41 cmol(+) kg -1 soil for topsoils and 21 -42.6 cmol(+) kg -1 for subsoils). All studied pedons had pH NaF > 9.5, reflecting an exchange complex dominated by amorphous Fe and Al oxides and/or humus complexes. Phosphate retention capacity (PRC) ranged from 25 to 97% and one pedon (MWZ 04) met the andic properties requirement of PRC ≥ 85%. SiO 2, Al 2 O 3 and Fe 2 O 3 ranged from 46.5 to 62.1%, 26.3 to 38.4% and 4.0 to 9.8%, respectively. On the basis of computed Chemical Index of Alteration (CIA), the degree of weathering of the studied pedons followed the trend NDE 01>MKY 03>MKW 01>KYE 01>IFIG 02>MWZ 04. According to USDA Soil Taxonomy, the studied pedons were classified as Alfisols (pedons MKW 01, MKY 03 and NDE 01), Inceptisol (pedon IFIG 02), Andisol (pedon MWZ 04) and Entisol (Pedon KYE 01), respectively correlating to Alisols, Cambisol, Andosol and Umbrisol of WRB for Soil Resources. The studied soils were generally rated as having low to medium fertility.

Background: Manihot esculenta, the most important tropical root crop which supply dietary staple food for about 800 million
populations worldwide. Twenty soil profiles that represent the soil Pedology and soil quality are similar in their concept in
relation to soil formation. In this regards, soil quality can be considered as part of the science of pedology. Significant
differences in yield of Tapioca (Manihot esculenta) with selected soil properties and subsequent interpretations as influenced
by land use are explained.

Methods: Soil samples were taken from designated pedogenic horizons for physico-chemical properties in the laboratory. Soil
textural class, saturated hydraulic conductivity, Cation Exchange Capacity, Base Saturation Percentage, soil organic carbon,
exchangeable cations, available N, P, K content and available micronutrients were analysed. The general fertility of the soils in the
area is discussed highlighting their potentials and constraints.

Result: A comprehensive analysis of soils in the study area showed that shallow soil depth of <47 cm and more clay of 44% with
high bulk density of 1.4 gcc-1, low hydraulic conductivity of 0.12 cmhr-1, low base saturation percentage of 77%, more exchangeable
sodium percentage of 7.96% with low available N, P and K of 110, 10.75 and 142.25 kg ha-1, respectively in low yielding soils are
the major constraints in the tract might behind the yield differences in Cassava.

La caracterización y la abundancia de la macrofauna del suelo y su relación con la morfología del suelo, fueron evaluadas en áreas de fragmentos forestales de bosques secundarios en el Centro para la Biodiversidad y el Turismo del Amazonas, del Servicio Nacional de Aprendizaje - SENA, en Leticia, Amazonía colombiana. La macrofauna del suelo (invertebrados mayores o iguales a 2 mm de diámetro) fue evaluada en dos períodos estacionales (mayo y octubre) con diferentes registros de precipitaciones. Fue encontrado una abundancia total de 5332 individuos de la macrofauna del suelo, distribuidos en 14 órdenes taxonómicas. El fragmento forestal conservado (FFC) fue el área que registró una mayor diversidad florística, y presentó la mayor densidad de la macrofauna del suelo en ambos periodos de muestreo. Los grupos de insectos Isoptera y Formicidae, fueron predominantes, sobre todo, en el FFC. Las comunidades de macrofauna del suelo no detectaron correlaciones significativas con las variable...

In order to diagnose the extent of development of some gypsum soils and their suitability for agricultural production, prepare maps of the spatial distribution of gypsum, and thus prepare a digital spatial database that fulfills the requirements for successful management of agricultural lands, five gypsum chain units were selected in the city of Al-Dur in Salah al-Din Governorate, and 5 soil beds were dug and models were taken from each horizon representative of the soil. Then, 41 surface samples were taken, representing all the series of the region, in order to prepare a map of the spatial distribution of gypsum using geospatial techniques. The results showed the diagnosis of the ochric epipedon surface horizon and the subsurface diagnostic horizon, the Gypsic Endopedon, in series A3.3 and A1.1, and the presence of gypsum in the form of gypsum cones in these horizons. The results of the spatial distribution map also revealed that the type of gypsum with a high content occupies a large area in the study area, estimated at about 44.26 km2, which leads to a problem in root growth and obstruction of the root system, which negatively affects the productivity of the crop and thus will negatively affect the productivity of agricultural lands, which requires the development of plans. Successful management achieves the preservation of the soil resource in order to achieve sustainable development goals of providing food and preserving these natural resources.

In order to diagnose the extent of development of some gypsum soils and their suitability for agricultural production, prepare maps of the spatial distribution of gypsum, and thus prepare a digital spatial database that fulfills the requirements for successful management of agricultural lands, five gypsum chain units were selected in the city of Al-Dur in Salah al-Din Governorate, and 5 soil beds were dug and models were taken from each horizon representative of the soil. Then, 41 surface samples were taken, representing all the series of the region, in order to prepare a map of the spatial distribution of gypsum using geospatial techniques. The results showed the diagnosis of the ochric epipedon surface horizon and the subsurface diagnostic horizon, the Gypsic Endopedon, in series A3.3 and A1.1, and the presence of gypsum in the form of gypsum cones in these horizons. The results of the spatial distribution map also revealed that the type of gypsum with a high content occupies a large area in the study area, estimated at about 44.26 km2, which leads to a problem in root growth and obstruction of the root system, which negatively affects the productivity of the crop and thus will negatively affect the productivity of agricultural lands, which requires the development of plans. Successful management achieves the preservation of the soil resource in order to achieve sustainable development goals of providing food and preserving these natural resources.

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.

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 km 2 .

The study area was chosen within the agricultural lands in the north of Kirkuk governorate to prepare a map of organic matter and calcium carbonate content. It identified three sites in Kalwor, Shwan, and Altun Kupri and collected 20 representative surface samples of the soil of agricultural lands in these sites. The maps were prepared in a software environment Arc GIS. 20 surface samples of soil from sites north of Kirkuk were chosen, representative of the nature of land uses, including field crops, rangeland, and barren soils, to study the spatial variations of some chemical soil characteristics of Kirkuk Governorate. The results revealed the nature of spatial variations in the content of organic matter, as it ranged between (0.58-19.54) g kg-1 , where the highest value was reached in ton coopers in lands exploited by growing field crops represented by corn, while the calcium carbonate content ranged between (208-365) g kg-1 .In conclusion, moderate organic matter content was dominant, specifically in exploited agricultural lands that follow a good soil management system, while the very abundant and plentiful variety was in lands that were not agriculturally exploited. The very high content of calcium carbonate is prevalent in most of the lands of the study area, which need agricultural land management, especially because they suffer from a specific factor, which is the high content of calcium carbonate, and in the future, it may lead to desertification of these lands.

Soil compaction is a widespread degradation process in forest sites. Soil degradation occurring on the structural formation of a natural soil system by rainfall or mechanical outer forces generally results in soil particles to be rearranged tighter than its previous status. In this case, soil compaction -defined as the increase in bulk density of soil- develops with negative effects on soil-plant-water relations. With the compaction, the density of soil increases while the porosity rate decreases, creating a harder formation in soil and consequently lower degree of hydraulic conductivity. Higher soil compaction usually occurs in densely used places including recreational areas, settlements, logged forests, fruit gardens, agro-forestry systems and nurseries. The compaction may occur naturally, but it can also be started by outer factors such as soil preparation tools, heavy equipments, tire traffic, livestock grazing or fires. Besides causing deterioration on physical and hydrologica...

Soil electrical conductivity (EC) is a soil quality indicator that is associated to attributes of interest for site-specific soil management such as soil moisture and texture. The present study performed spatial monitoring of soil moisture in two experimental fields of Brazilian soils for two consecutive years and modeled its influence on soil EC. Soil EC, moisture and clay content were evaluated by statistical, geostatistical and regression analyses. Semivariogram models, adjusted for soil moisture, had strong spatial dependence, but the relationship between soil moisture and soil EC was obtained only in one of the experimental fields, where soil moisture and clay content range was higher. In this same field, the correlation coefficients between soil moisture and clay content were above 90%. In the second field, the low soil moisture and clay content range explain the absence of a relationship between soil electrical conductivity and soil moisture.

A soil profile representative of typical soils of Mwala District, Kenya, was dug to study its morphology, soil physico-chemical characteristics and to classify it using two internationally known soil classification systems. Disturbed and undisturbed soil samples were taken from designated pedogenic horizons for physical and chemical analysis in the laboratory. Soil morphological observations revealed that the pedon is well drained and very deep with dark brown to dark yellowish brown topsoil overlying brown to strong brown sandy clay loam to sandy clay subsoil.