Argillic Horizons Research Articles

Pedological Factors, Classification, Physical-Chemical Properties and Management Strategies of Inceptisols in the Boca Formation of Temanggung, Cetral Java, Indonesia (Study: Horticultural Land Management)

Abstract The purpose of this research is to see the development of soil and management strategy of the boca formation in the Temanggung, Central Java, Indonesia. The boca range in Temanggung are hills located in Danurejo, Central Java, which are part of the old Sumbing mountain formation. This area is thought to be an intrusion area of cracks from the old Sumbing mountain, located at the foot of the mountain between Sumbing and Sindoro mountains. The boca formation is located at 705.9 m above sea level (m asl), in general the Boca formation consists of breccia, andesite, anglomerate and tuff. Vegetation that grows in the boca range includes bamboo and cotton. Soil genesis in the boca range has not yet reached an advanced stage of development characterized by the formation of an argillic horizon. The observed soil shows a diagnostic horizon, the cambic horizon. The soil acidity level (pH 5-6.5), falls into the slightly acidic class, with a texture dominated by geluhan. Based on the data obtained through field survey and laboratory analysis, the soils in the boca range are classified into Inceptisols based on USDA, Cambisols based on PPT and Cambisols based on WRB with ustic regime.

STUDY SOIL DEVELOPMENT AND CLASSIFICATION IN ERBIL PROVINCE, KURDISTAN, IRAQ USING MATHEMATICAL INDICES

The study area located at Erbil province, Kurdistan, Iraq, seven pedons were elected. Twenty-one soil samples were collected in the study area. Different physiochemical and fertility indices have been used to determine the soils development, despite of generating interpolated maps for them. The results indicated that the low values of clay were found in the less pedon developed and argillic horizon existed in development pedons. Study soils were non-saline, slightly to moderately alkaline, and had relatively high bulk density values. Organic matter is concentrated at the soil surface. Considerable total carbonates are found in studied soils and have irregular distribution manner, as well as have high CEC values. Low C/N ratio due to highly decomposed organic matter. The active CaCO3/total CaCO3 increases with depth in all pedons, while, slightly fluctuated in one pedon. The ratio of total clay in BH /AH was found just in some pedons and more than (1) therefore these soils are considered development, and are more developed depending on the ratio of fine clay/total clay. Soils are classified into three groups the first was the least developed soils, the second group has the most development. Third group are intermediate in their development. Pedogenic processes included leaching, illuviation, eluviation, alkalization, humification, lessivage, desalinization, calcification, decomposition, and littering. Studied soils classified as Inceptisols and Mollisols.

Fractionation of rare earth elements in soil profiles along an elevation gradient in central Taiwan

The distribution of rare earth elements (REEs) in soils is affected by climate, which is one of the main factors controlling soil formation. However, variations in the geochemical behavior of soil REEs with pedoclimatic changes have rarely been investigated. This study determined the mobilization/retention and fractionation of REEs in nine soil profiles derived from sandy shale along an elevation gradient from 49 m to 2394 m above sea level in the Central Mountain Range of Taiwan. The experimental results indicated a gradually decreased ΣREEs trend with increasing elevation/rainfall. Clay content significantly (p < 0.05) correlated with REEs, which accumulated in argillic horizons. Moreover, a decreasing GdN/YbN ratio with increasing secondary minerals (i.e., clay and pedogenic Fe and Al oxides) implied their preferential sequestration tendency for heavy REEs over light REEs. This preferential association coupled with intensifying illuviation along the climatic gradient, resulted in increasing LaN/SmN and decreasing GdN/YbN ratios with increasing weathering degree and elevation (p < 0.01). Our results demonstrate that in the studied humid tropical region, increasing moisture availability caused by higher rainfall and lower air temperatures with rising elevation has led to stronger illuviation and more advanced soil development, which is reflected in REE fractionation and can be quantified by the ratios GdN/YbN and LaN/SmN.

Characterization and classification of soil resources of hittinahalli sub-watershed derived from basalt in Northern dry zone of Karnataka

Eighteen Typical pedons representing upland, midland, and lowland forms in a Hittinahalli subwatershed of Vijayapur district were studied for their morphological characteristics and physicochemical properties. The soils were shallow to very deep (25 to &gt;150 cm), very dark brown to black (Munsell color chart) and moderately well to poorly drained. The soil structure changes from weak, medium sub- angular blocky on the surface to moderate, coarse sub-angular blocky in the subsurface horizons. The soils are moderately alkaline to strongly alkaline (7.59–9.41), low to high in organic carbon (0.08–0.75 g/kg). The pedons on uplands exhibit the development of an argillic horizon (Bt). The pedons on the midlands and lowlands have cambic horizons (Bw), classified as Verisols and Inceptisols, respectively. The lowlands (P6, P10, P16, and P18) and midlands (P7, P8, P12, P15, and P17) are classified as fine, mixed, Iso-hyperthermic, and Typic Haplustalfs.

Palaeosols as stratigraphic proxies and palaeosurface markers in distributive fluvial systems

Palaeosols can be used as stratigraphic proxies, palaeosurface indicators, and palaeorelief reconstitution tools, as they reflect a complex interrelationship between sedimentation, erosion, non-deposition, and pedogenesis. The objective of the article was to estimate the relative time of formation of palaeosols of the Marília Formation, to determine the periods of non-deposition and non-erosion, indicative of stabilities on the surfaces, and to interpret the profiles as markers of palaeosurfaces in distributive fluvial systems (DFS) of the Late Cretaceous of Brazil. Eleven sections of the Marília Formation (S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, and S11) were described, comprising forty-three profiles. The pedotypes classification (polygenic, compound, and cumulative) and the determination of palaeosols' relative formation time and residence time were based on the specialized literature. The reconstitution of pedosedimentary cycles considered the dynamics of sedimentation, erosion, and pedogenesis. Eight sedimentary cycles and 45 pedosedimentary cycles were interpreted. All the Maastrichtian pedosedimentary cycles of the Bauru Basin corresponded to depositional cycles interspersed with erosive and pedogenic processes. Palaeosols with argillic (Btk, Bt, Bss) and calcic (Bkm) horizons, developed from fluvial sandstones, evolved in processes predominantly after the deposits, with later erosive processes. However, although most of the profiles developed in periods between deposits and erosion, pedogenic processes also occurred concomitantly with the sedimentary cycles, favouring the formation of polygenetic profiles, which presented the longest pedogenic cycles in chronological terms. Palaeosols with argillic horizons can be important stratigraphic landmarks. They represent stopping moments in erosion and sedimentation of up to 1.374 My, thus consisting of the closing of high-frequency depositional cycles. Although palaeosols can demonstrate relief inversion and pedotypes with Bt-horizons can indicate ancient regional surfaces, the complete reconstitution of the topography becomes more possible at the local level, in a palaeoslope approach, due to the variability of pedofacies.

Assessing profile uniformity of soils from weathered clastic sedimentary rocks in southwest China

The 41 pedons from weathered clastic sedimentary rocks were selected to assess the parent material and soil profile uniformity. The results can help to divide argillic horizon and identify the differences among the various soil profiles in soil quantitative classification. The Ti/Zr ratio and particle size distribution of soils were analyzed to quantitatively assess parent material uniformity. Next, the morphological characteristics, physical and chemical properties, generalizable horizon development indices and geochemical element characteristics of soils were analyzed to quantitatively assess soil profile uniformity. Finally, the coefficient of variation (CV) of soil properties were used as the input variables of the random forest model to assess soil profile uniformity. The results showed that the parent materials were all uniform in terms of geochemical elements, while 63% were assessed as exhibiting lithologic discontinuity in terms of particle size caused by different surface erosion force of slope water. In addition, 20% of the profiles showed large internal color differences, and the generalizable horizon development indices suddenly changed along the vertical direction. The physical and chemical properties and geochemical elements varied greatly in the principal component analysis grouped by parent material, being assessed as soil profile inhomogeneous due to complex abundant clastic sedimentary rocks and different slope terrain conditions. In the pedogenesis, the slope deposit and soil forming process can cause 85% of soils with lithologic discontinuity to exhibit soil profile uniformity. When assessing soil profile uniformity, the CVs of the clay-free particle size distribution were the best input variable of the random forest model, and it is most convenient to use the five indices of CVs of Al, Si/Al ratio, clay, total phosphorus and Na as the input variables.

Litologie a paleopůdy klikovského souvrství ve vrtu 2140 01T1 Dunajovice, třebonská pánev

The 2140 01T1 borehole sampling the Late Cretaceous non-marine strata of the Klikov Formation in the central part of the Třeboň Basin in southern Bohemia provided ~ 70 m thick alluvial succession composed of alternating sandstone and mudstone intervals that overlays deeply weathered crystalline basement. The mudstone interval in the lower part of the Klikov Formation is separated by sandy layers into several 2–4 m thick fining-upward units. The sharp-based sandy layers with fusain, carbonized stems and rip-up clasts of underlying mudstone are interpreted as avulsion deposits. They grade upwards into heterolithic sand-silt sequence and mottled massive mudstone with burrows, rhizohalos and variably developed pedogenic features. Such cyclic arrangement probably reflects autogenic processes on distal floodplain with episodic deposition and upward increasing subaerial exposition and pedogenic overprint. In the middle to upper parts of the Klikov Formation up to 6 m thick channel sandbodies with sharp erosional bases cutting into the underlying laminated sand-silt heteroliths of channel levee deposits occur. The thickness of the single-storey sandbodies corresponds usually to c. 2 m which suggests up to 3 m deep channels during bankfull discharge. The thicker multi-storey sandbodies record channel amalgamation on the alluvial ridge or shallow paleovalley fillings. The sandbodies grade upwards to massive mudstones of abandoned channel fills and floodplain deposits. These floodplain units are up to 8 m thick and consist of variegated massive mudstones interrupted by discrete up to 1 m thick fining upward layers of rippled sandstone representing crevasse splay deposits. Depositional context including preserved levee deposits, abandoned channel fillings and floodplain finegrained deposits suggests rather higher sinuosity of the formative rivers. Palaeosol profiles represent pedogenically modified floodplain fines with gradational bases and sharp erosive top surfaces. At least 10 palaeosols were identified in the measured section, forming mostly discrete profiles up to 2 m thick consisting of several B-horizons that differ in the degree of the soil structure development, colour, mottling, grain size, presence of clay hypocoatings and bioturbation index. The most common Bw horizons form lower parts of the profiles and have no or only a weakly developed angular blocky structure (ABS). The typical mottling is caused by a hierarchical system of vermicular greenish-grey reduction rhizohalos, that may be filled by silt to sand or illuviated clay hypocoatings and probably follow the original plant root system. Some patches have diffuse orange rims of iron oxides, probably represented by goethite. Mudstone of Bsst horizons displays well-developed ABS with rare wedge-shaped peds and contains a number of illuviated clay skins and redox depletions. Vertic features like fine cracks filled by sand are common, and slickensides with clay hypocoatings occur rarely. Mudstones of Bt horizons contain a number of illuviated clay hypocoatings filling root channels or interpedal cracks, while the Bss horizons exhibit well-developed ABS with slickensides and contain a number of vertical cracks filled by sandy grains. Palaeosol profiles represent mainly argillisols and vertic argillisols with transitions to argillic vertisols. Poorly developed argillic to vertic protosols are also common. Palaeosol profiles differ mainly in the degree of structural development/maturity, which is given by various lengths of exposition to similar climatic conditions. Vertical distribution of palaeosols reflects their position in the alluvial landscape with locally specific hydromorphic conditions rather than a distinct climatic trend. Most of palaeosols exhibits downprofile translocation of clay (illuviation) leading to the formation of argillic horizon, which typically develop on stabilized landscape in humid climate with seasonal moisture deficit.

Differentiation of fine-textured podzolic soils controlled by climate and landscape in Taiwan

Podzolization is considered to be facilitated by factors such as cool and humid climate, sufficient supply of certain types of organic acids, and coarse-textured parent materials. However, podzolic soils in subalpine areas in Taiwan are characterized by clay content higher than 30%, which differed from that in typical podzolic soils in temperate and boreal regions. This study examined the importance of factors controlling the differentiation of fine-textured podzolic soils in Taiwan. Samples from 31 pedons were examined in this study, and the pedons were grouped into four types, namely Spodosols, Ultisols, Inceptisols, and Inceptisols with placic horizons. Soil colors with 7.5YR 5/6 (the accumulation of spodic materials) and micromorphological observation of oriented clay coatings in the Spodosols confirmed the occurrence of podzolization and clay illuviation, and the selective extraction of Fe and Al confirmed that the Spodosols (Type I) had a higher accumulation of organometallic complexes than the other podzolic soils. A two-step mechanism, namely (1) clay illuviation at an early stage of pedogenesis and (2) podzolization after the canopy vegetation formed, was proposed for the formation of fine-textured Spodosols. Photomicrographs of the Ultisols (Type II) displayed clay hypocoatings masked by spodic materials, and argillic horizons were characterized by a high amount of nanocrystalline iron and high optical density of the oxalate extract. However, the accumulated nanocrystalline iron oxides in the Ultisols were due to the degradation of organic matter under high summer temperatures. Moreover, the leaching of iron in the albic horizons of the Ultisols was attributed to episaturation caused by high clay contents. The Inceptisols (Type III) were transitional soils before forming the Spodosols or the Ultisols, and high clay contents further induced episaturation and formed placic horizons in the Inceptisols (Type IV). Principal component analysis revealed that soil texture and precipitation were the main factors controlling the differentiation of podzolic soils in Taiwan. These factors determined the penetrability and leaching potential of soils, and only the coarse-textured soils with higher leaching potential had the chance of developing Spodosols. However, the developments of Ultisols and Inceptisols with placic horizons were controlled by air temperature and landscape, namely elevation and slope. The bleached E horizons in podzolic Ultisols were attributed to their flat landscape, which favored episaturation and caused the reduction of iron. Low elevation and high temperature in these regions also facilitated the degradation of organic matter and the accumulation of nanominerals.

The influence of soil development on the depth distribution and structure of soil microbial communities

Although it has been shown that the interaction of climate and time shape the dynamics of soil organic matter (SOM) storage and preservation in soil, the role of soil microbial communities in this dynamic remains unclear. Microbial communities are present throughout soil profiles and likely play critical roles in SOM and nutrient cycling, however the influence of other factors such as soil development (i.e., age) and the composition SOM on microbial community variation with depth has yet to be quantified. Improving our understanding of the relationship between soil development, soil depth, and microbial communities may provide insight to the critical role they play in cycling and preservation of SOM, as well as more mechanistic predictions of the response of soil communities to change, such as landscape-scale changes in available moisture or temperature regimes. Here we compare soils spanning a soil age by climate gradient (i.e., climo-chronosequence) to better understand the mechanisms which influence soil microbial community structure and the molecular composition of SOM. While we observed little depth-dependence in metrics of microbial community structure (i.e., composition, diversity, dissimilarity) across the range of soil development under a wetter climate, we found significant depth-dependent changes in community metrics under a drier climate, which became more pronounced as soils became older. This shift in bacterial and archaeal community structure and diversity is most apparent below a clay-rich argillic horizon formed in the older, drier soils. The molecular composition of SOM as measured by high resolution mass spectrometry (i.e., FTICR MS) also exhibited similar shifts in composition with soil depth and age. Our results highlight how soil moisture shapes the interaction of soil development, SOM, and microbial community composition. Differences in the moisture regime between our two study sites drive differences in biogeochemical depth gradients and subsequent variation in soil microbes and SOM. This suggests that knowledge of not just the pedogenic trajectory of soil development, but also the spatial position relative to distinct pedogenic features, are important for explaining variations in the depth-dependencies of microbial communities and associated SOM.

Mineralogical and Elemental Trends in Regolith on Historically Managed Sites in the southeastern United States Piedmont

AbstractThe deep regolith of the southeastern United States has undergone rapid erosion in the last two centuries due to intensive agricultural practices, which has altered the landscape and its inherent fertility. Parent material, landscape position, and land use are important factors in controlling the mineral and elemental composition of soil profiles. Independent quantitative X-ray diffraction (QXRD) and whole-rock chemical analysis of eight weathering profiles agreed well and allow mineral reaction pathways to be constrained as particles are conveyed in the subsurface. QXRD analysis of saprolite, argillic, and soil A-horizons in the profiles highlights the imprint of bedrock on the regolith, which includes Neoproterozoic meta-tonalitic to meta-granodioritic and Paleozoic meta-granitic to biotite- and amphibolite-gneissic lithologies. Also, aeolian input slightly influenced A-horizon composition. The clay mineral assemblage is dominated by kaolinite, but profiles differ in the amount of interstratified clay minerals, halloysite, hematite, goethite, and gibbsite. Rare-earth element totals vary between 30 and 1048 ppm and are generally correlated positively with clay and clay mineral content. Eu and Ce anomalies reflect parent rocks and subsequent hydrolysis and redox history, with trends depending upon landscape position and clay content in the weathering profile. Weathering profiles on a high-order interfluve and those that were actively cultivated have thick argillic horizons (as defined by clay mineral abundance) and are depleted in alkali and alkaline-earth elements. Profiles proximally developed on old-field pine and never-cultivated hardwood forest land do not show large differences in mineral composition trends, whereas profiles on old-field sites with ongoing cultivation exhibit assemblages enriched in clay minerals and (oxyhydr)oxides. Old-field pine sites that were historically eroded by previous cultivation tend to have shallower and thinner argillic horizons, which may well impact critical-zone processes involving gas and water fluxes. This study highlights that mineral compositions of deep regolith, saprolite, and shallow soil horizons are dependent on local geomorphology (i.e. watershed- and hillshed-orders). Quantifying soil and regolith compositional trends across the landscape is a prerequisite for determining rates of chemical and physical erosion on human and geologic time scales.

Çanakkale’de Farklı iklim Koşullarının Toprak Oluşumuna Etkisi

Çanakkale İli Yenice (Ahiler köyü-P1) ve Ezine (Kızıltepe köyü-P2) ilçelerinde yürütülen bu çalışmada, andezitik kayaçlar üzerinde farklı yağış ve sıcaklık koşullarında oluşmuş iki toprak profili incelenmiştir. Yenice ilçesinin yıllık ortalama yağış miktarı ( 847 mm) Ezine ilçesinden (547 mm) daha fazladır. Arazide morfolojik tanımlamaları yapılan profillerden horizon esasına göre alınan toprak örneklerinde XRD (X Ray Difraksiyon), SEM (taramalı Elektron Mikroskobu) ve EDS - EDX (enerji Dağılımlı X-ışını Spektroskopisi) ve major oksit gibi bazı fizikokimyasal analizler ve mineralojik analizler yapılmıştır. Oksit analizlerden CIA (kimyasal ayrışma indeksi), PIA (plajioklas alterasyon indeksi) ve SİO2/Al2O3 gibi bazı ayrışma oranları hesaplanmıştır. Profil 1 O-A -Bt-C-R ve profil 2 ise A-Bw-C horizonlarını içermektedir. Profil 1 yüzeyde kumlu tın, yüzey altında ise kil tın ve kil, profil 2 ise genellikle kumlu kil tın bünye sınıfındadır. Yıkanmanın etkisiyle P1 de bir argillik horizon oluşmuşken P2 de kambik horizon mevcuttur. P1 de katyon değişim kapasitesi (KDK) argillik horizonda 42.48 cmolkg-1 iken P2 nin kambik horizonunda 26.72 cmolkg-1 olarak belirlenmiştir. P1’in CIA ve PIA ayrışma indeksleri P2’ye göre daha yüksek bulunmuştur. Buna göre P1 de feldspatların daha fazla ayrıştığı ve P2 ye göre daha yaşlı bir profil olduğu saptanmıştır Bunun yanında XRD analizlerine göre P1 de kaolinit mevcut olup feldspatlardan albite rastlanmazken P2 de kaolinite rastlanmamış ve önemli miktarda albit belirlenmiştir. Toprak profilleri toprak taksonomisine göre sırasıyla profil 1 Lithic Haplustalf, profil 2 ise Humic Dystroxerepts; WRB sınıflamasına göre profil 1 Epileptic Luvisols (Abruptic), profil 2 ise Haplic Cambisols (Dystric) olarak sınıflandırılmıştır. Çalışma sonuçları benzer topoğrafik koşullarda ve andezitik kayaçlar üzerinde oluşmuş iki toprak profilinde, iklim parametrelerinden yağıştaki farklılıkların toprakların profil yapısı, ayrışma düzeyleri, fiziko-kimyasal özellikleri ve toprak taksonomisini etkilediğini göstermiştir.

Stoichiometry of base cations and silicon during weathering of a deep soil profile derived from granite

Evaluation of the stoichiometry of base cations (BCs, including K+, Na+, Ca2+, and Mg2+) and silicon (Si) (BCs:Si) during soil mineral weathering is essential to accurately quantify soil acidification rates. The aim of this study was to explore the differences and influencing factors of BCs:Si values of different soil genetic horizons in a deep soil profile derived from granite with different extents of mineral weathering. Soil type was typic acidi-udic Argosol. Soil samples were collected from Guangzhou, China, which is located in a subtropical region. To ensure that the BCs and Si originated from the mineral weathering process, soil exchangeable BCs were washed with an elution treatment. The BCs:Si values during weathering were obtained through a simulated acid rain leaching experiment using the batch method. Results showed that soil physical, chemical, and mineralogical properties varied from the surface horizon to saprolite in the soil profile. The BCs:Si values of soil genetic horizons during weathering were 0.3–3.7. The BCs:Si value was 1.7 in the surface horizon (A), 1.1–3.7 in the argillic horizon (Bt), and 0.3–0.4 in the cambic (Bw) and transition (BC) horizons, as well as in horizon C (saprolite). The general pattern of BCs:Si values in the different horizons was as follows: Bt > A > Bw, BC, and C. Although BCs:Si values were influenced by weathering intensity, they did not correlate with the chemical index of alteration (CIA). The release amounts of Si and BCs are the joined impact of soil mineral composition and physical and chemical properties. A comprehensive analysis showed that the BCs:Si values of the soil derived from granite in this study were a combined result of the following factors: soil clay, feldspar, kaolinite, organic matter, pH, and CIA. The main controlling factors of BCs:Si in soils of different parent material types require extensive research. The wide variance of BCs:Si values in the deep soil profile indicated that H+ consumed by soil mineral weathering was very dissimilar in the soils with different weathering intensities derived from the same parent material. Therefore, the estimation of the soil acidification rate based on H+ biogeochemistry should consider the specific BCs:Si value.

Morphophysical and Nutrient Characteristics of Degraded Soils in Sta. Rita, Samar, Philippines

The productivity of degraded soils greatly depends on a good understanding of their characteristics. Hence, the study was conducted to determine the morphological, physical and chemical characteristics of degraded soils in Sta. Rita, Samar, Philippines. Four representative soil profiles located in different physiographic positions were examined, characterized and sampled. The examination was conducted using a pit measuring approximately 1-m wide and 1-m depth. Soil samples were collected from each horizon, processed and subjected to field and laboratory analyses. Results showed that the soils were derived from sedimentary rocks (i.e., shale). Well-developed soils were found on the summit and foot slope position (horizon sequence: Ap-Bt-BC-C), while moderately developed soils were obtained in the middle slope position (horizon sequence: Ah-Bt-C). Soils had a clayey texture with moderate bulk density, porosity and water holding capacity. They were friable to firm when moist, but plastic and sticky when wet. The soils were highly acidic (soil pH close to 5.0). They had a moderate amount of organic matter, low total nitrogen (N) and low available phosphorus (P); all of which had decreased amounts with soil depth. Exchangeable bases (calcium, magnesium, potassium and sodium) were high in most soil profiles. Thus, N and P fertilization and organic matter addition are highly recommended to increase the productivity of these degraded soils. Moreover, the soils were classified as Typic Hapludalfs or Haplic Luvisols because of their development degree. They were mature with the presence of an argillic horizon (B horizon with high clay accumulation) and high base saturation.

The Investigation of Ultic Horizon on Andisols Derived from the Eruption of Mount Tilu (Pleistocene, Basaltic) in West Java, Indonesia

DOI:10.17014/ijog.9.2.159-172Ultic is the soil characteristics in soil taxonomy when argillic or kandic horizon is found within the depth of 125 cm with the base saturation of less than 35 % on the overall of upper 50 cm. The purpose of this research is to investigate whether ultic horizon was found in the soil developing from the Pleistocene eruption of Mount Tilu (basaltic parent materials), in West Java, Indonesia. The method used was descriptive and comparative surveys of three profiles in the area around Mount Tilu, including the investigation of andic soil properties and the formation of argillic or kandic horizon. The result showed that the soils fulfilled the requirements of andic soil properties to be classified as Andisols. Soil never dried for ninety days cumulative (udic) to be classified as Udands. There were Fulvudands and Hapludands in this location. Accumulation of clays was more than 1.2% higher than the overlying horizon found at the depth of 90, 79, and 51 cm in those three profiles. Base saturation in upper 50 cm ranged from 1.07 to 6.86 cmol kg-1 or less than 35 %, making the soils were classified as Ultic Fulvudands and Ultic Hapludands. The high rainfall in the tropics and Pleistocene age led to the leaching of clays for a long period to form the argillic horizon. The influence of rain was stronger than the basaltic parent materials in forming Ultic Hapludands. Basaltic parent material was not strong enough to produce base saturation of more than 35 %.

Assessment of sesquioxides status of some uplands soils in humid southwest Nigeria

Assessment of some sesquioxides in the upland soils in southwestern Nigeria was undertaken to evaluate their degree of weathering under humid tropical conditions. Samples were taken from genetic horizons of eight soil profile pits sited at different physiographic positions along two toposequences in southwestern Nigeria. The samples were analyzed for gravel content, particle size distribution, bulk density, pH, organic carbon, total nitrogen, available P, exchangeable bases, crystalline and amorphous forms of Fe and Al, using standard procedures. Sand fraction ranged from 31–76% (54.49±11.34), silt from 3–19% (10.21±3.61) and clay from 10–55% (35.3±9.7). Bulk density increased with profile depth, ranging between 1.12 and 1.64g cm-3 (1.39±0.13). The pH was low (4.2–6.1; 5.0±0.55), organic carbon content ranged from 0.75–15.99g kg-1 (5.79±3.49) with higher values in the surface horizons. Total nitrogen content ranged from low to medium (0.13–2.75g kg-1; 1.16±0.49) while available phosphorus ranged from 0.49–11.63mg kg-1 (4.30±3.57) across the horizons. Crystalline forms of Fe (Fed) and Al (Ald) ranged from 10.26–39.82g kg-1 and 0.41–1.80g kg-1, respectively while the amorphous forms (Feo and Alo) ranged from 0.41–2.60g kg-1 and 0.83–1.64g kg-1, respectively. The crystalline forms of Fed and Ald were more dominant over the amorphous forms of Feo and Alo. The argillic (Bt) horizons of pedons had significant accumulation of clay particles and free iron. The weathering indices of clay and free iron accumulation in argillic (Bt) horizons of the pedons indicated that the soils of the study area were well-drained, deeply weathered and intensely leached with few weatherable minerals available for plant uptake.

Characterization and Taxonomic Classification of Soils under a Toposequence Located at North-Eastern Ghat Agro-Climatic Zone of Odisha, India

The present investigation was carried out to study the characterization and Taxonomy classification of soils under a Toposequence located at North-Eastern Ghat Agro-Climatic zone of Odisha, India. Three representative pedons of the Nayagarh district located in different topographic positions of upland (pedon 1), medium land (pedon 2) and low land (pedon 3) respectively were studied for their morphology, physico-chemical characteristics and taxonomic classification. Results show that the bulk density and particle density found with higher values in the lower horizon and lower values in the upper horizon. Total porosity values found to be higher in upper horizons and lower in the lower most horizons. The soil pH found to gradually increase with increasing depth in all three pedons. The OC content decreasing along with depth in all the pedons. In pedon 2 and 3, fully developed genetic horizons with distinct sub-horizons within the B horizon. However, in pedon 1, no such horizons are developed. The clay content increases in pedon 2 and 3 from upper sub-horizon to the lower sub horizon of B horizon with increasing depth which could be due to the process of illuviation of clay and development of argillic horizon (Bt). Pedon 1, are classified under order Entisols; while that of pedon 2 and 3 under soil order of Alfisols. Pedon 1, are classified under sub order Orthents, great group Ustorthents and sub group Typic Ustorthents; while that of pedon 2 and 3 are classified under sub order Ustalfs, great group Haplustalfs and sub group Udic Haplustalfs.

Detailed Soil Survey Field and Laboratory Data as a Critical Tool for Optimizing the Arable Cropping Capability Evaluation of a Representative Episaturated Soil Pedon in Greece

The objective of the present work is to contribute to the examination of the interconnections between soil classification/soil mapping and soil capability for agricultural use. A pedon scale analytical field along with laboratory data of an episaturated agricultural soil of Thessaly (Greece), allowed for the optimization of soil fertility class evaluation and its corresponding agricultural value. Specific soil properties, low chroma colors and the distribution of redoximorphic features within the soil profile (Fe-Mn concretions) revealed the presence of impermeable argillic horizons, resulting in a perched water table in late winter and spring. The evaluation of the soil pedon was carried out through the accurate parameterization and implementation of a technical soil classification system and a soil rating method, both of which are well known worldwide, and which use detailed soil survey data. The results confirmed the general principle that only by using detailed soil survey field and laboratory data can any technical soil classification system or soil rating method be adapted and properly applied. Both the classification system and the scoring methodology of the soil profile reached the same conclusion: characterizing the studied soil as of good potential for general arable cropping or as of fair agricultural value. This was achieved only by considering the phenomenon of episaturation, which emerged from the plethora of detailed soil survey data, guiding the classification system and the scoring methodology to produce reliability and represent real situation results.

Selenium Concentrations in Southeastern Missouri Soils and Its Impact on Livestock Nutrition

Selenium is a trace element in animal nutrition provided through forage. Vegetation should accumulate adequate levels to meet this livestock requirement. This study assessed southeastern Missouri soils for their selenium concentrations. Multiple sites across southeastern Missouri were sampled, from which a total of twenty-six soils were collected. Parent materials ranged from coarse to fine-textured alluvium and terrace deposits, colluvium, loess, limestone residuum and rhyolite residuum from poor to well-drained soils. The mean whole soil selenium contents ranged from less than 0.1 mg Se kg-1 for the Kaintuck pedons to 1.0, 2.2, and 2.4 mg Se kg-1 for the Irondale, Killarney, and Frenchmill pedons. For individual soils, Menfro pedons were deep, well-drained soils developed in loess. Paired Menfro pedons having similar soil morphology and having A-E-BE-Bt-C horizon sequences were selected and the greatest selenium concentrations were in the argillic horizons. Soils having fine textures (clayey) had moderate selenium concentrations, whereas soils having coarse textures (sandy) revealed minimal selenium concentrations. A wide soil selenium concentration variation was shown; however, no toxic selenium levels were measured. Therefore, soil selenium toxicity is not a regional issue. Noting that soil selenium concentrations in medium to fine-textured soils are appropriate for providing selenium to livestock, the need to artificially soil incorporate selenium or add selenium into the livestock ration remains critical for coarse-textured soils.

Genesis and Behavior of Sodic Soils in Humid Climates

Sodic soils are typically located in semi-arid to arid climates. However, sodic soils in continental humid climates are rare. As with sodic soils in dry climates, sodic soils in wetlands pose management difficulties for agriculture, forestry, or wild-life habitat. The typical practice of gypsum application is problematic given inability to provide drainage. Natraqualfs located in southeastern Missouri present an acid argillic horizon superimposed on a natric horizon, where the exchangeable sodium percentage and an alkaline reaction are characteristic attributes. Ferrolysis is an active soil process that is slowly degrading the natric horizon because of exchangeable Al3+ and H+ generation and re-stabilization of the soil structure, permitting leaching of the sodium.

Characterization and classification of the Mawer forest soils of Lesser Himalayas of North Kashmir

Soil is an important component of the forest ecosystem. The inventory and assessment of the forest soil resource provide critical baseline information on forest health and productivity. Therefore, a study for the characterization and classification of the soils of Mawer forest range of North Kashmir Himalayas was conducted. In this study, twelve representative soil profiles along with two altitude gradients on Northern and Southern aspects of Mawer forest range were evaluated for soil characterization and classification. The soils show varying degree of profile development varying from A-B to A-C type with the well-developed sub-surface argillic horizon (Bt) on moderately steep slopes and cambic horizon on steep slopes. The soils are silty loam to loam in texture, slightly acidic to alkaline (pH 5.5 to 6.8) in reaction, non-saline (EC 0.02 to 0.14 dS m−1) with higher organic carbon content on north-facing profiles. Available nutrients are higher on the northern aspect of surface horizons with higher calcium and potassium content on higher altitudes and magnesium and sodium content on lower altitudes. As per soil classification, major soils belong to Udothents and Haploudolls followed by Hapludalfs, Agriudolls, and Eutrochrepts at a great group level.