Soil Horizons

2003 9 served for agrarian settlement. Lewis and Clark objectively observed both gardens and deserts during the expedition and reported those observations in their journals. Lewis's reaction to the prairies of the Great Plains shows the extent to which he was a scientific observer of the landscape. He had heard that the prairies were like deserts ("barren, steril and sandy"), but objective observation showed them to be "fertile in the extreem.

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 Keys to Soil Taxonomy have expanded greatly since Soil Taxonomy (Soil Survey Staff, 1975) was first published. This expansion reflects our increased knowledge of soils, their diversity, and partly is a result of its application in areas where it had not been used before. Soil taxonomy committees with international membership have revised the system in order to improve its application to soils outside of the United States. Soil Taxonomy was developed in the U.S. but was intended from the beginning to be used worldwide. While it has not received universal international acceptance and likely never will, it is being used in many smaller countries that cannot afford the time and/or do not have the expertise to develop soil classification systems unique to their country. This expansion and modification has enlarged the Keys to such an extent that the system may be overwhelming to some readers or potential users. Length was identified by Swanson (1999) as a barrier to wider use of Soil Taxonomy; not all parts of the keys apply in relatively small geographic regions or countries. It is possible to make the keys more user-friendly by extracting only those parts that apply to a particular country or region. We developed Keys to Soil Taxonomy for Finland (Fig. ), published by USDA-NRCS , in an attempt to assist Finnish soil researchers. Taxa included in the Finland Keys occur or are likely to occur in that country, based on our knowledge of soils and landscapes, published data , data collected, and pedons described (Yli-Halla and Mokma, 1999) and sampled .. The Keys to Soil Taxonomy for Finland contain the criteria to identify diagnostic horizons and other diagnostic characteristics and to classify soils into soil orders, suborders, great groups, and subgroups. This represented a reduction from 869 pages, for the complete Soil Taxonomy (Soil Survey Staff, 1999) (326 pages in Keys to Soil Taxonomy (Soil Survey Staff, 1998) to 31 pages in Keys to Soil Taxonomy for Finland. Our objective in this article is to describe the process we used in preparing the Keys to Soil Taxonomy for Finland.

Spodosol is a soil order that is relatively easy to recognize in the field (Soil Survey Staff, 1999). The unique color pattern of a grayish E horizon and a dark reddish B horizon results from the eluviation and iIIuviation of C, AI, and Fe. The grayish colors are produced as organic C, coatings from the surface of soil particles, and AI and Fe released during weathering of minerals are eluviated. Podzol and Spodosol were derived from terms meaning "ashes" for the ashy gray E horizons. The accumulation of organometallic complexes in B horizons produces redder and darker colors. The upper subhorizon of spodic horizons usually has the reddest hues, lowest value, and/or highest chroma (Soil Survey Staff, 1999). Field identification of Spodosols is frequently complicated by the chemical criteria in the definition of the spodic horizon and spodic materials. Initial criteria that must be met by all horizons

On farms situated on slopes, such as those in the Western Highlands of Cameroon, the implementation of soil and water conservation techniques remains a major concern. The land preparation methods commonly practiced in the Western Highlands agro-ecological zone of Cameroon are ridging along the steepest slopes (RASS) and the flatbed (FB). Field observations showed FB and RASS promote erosion by runoff, thereby compromising some agriculture functions (environmental function, production function and even social function). In order to ensure soil stability and maintain good water quality for rivers, a new land preparation method, tied ridging (TR), was tested. Erosion by runoff tests were conducted with four blocks of three plots on each of the most commonly exploited slopes, namely 11% and 29% gradient. With the main crop in the area (potato, Solanum tuberosum L.), the performance of RASS, FB, and TR were compared during crop years 2013 and 2014. The water runoff and sediments were col...

A process-based model was developed to simulate for peat lands emission of the greenhouse gasses (GHG) CO 2 , CH 4 and N 2 O, soil subsidence and nutrient loading of surface waters. The model was calibrated and validated against data from two experimental fields in the Netherlands. With the validated model scenario studies were performed to quantify the effects of water management on GHG emission, soil subsidence and nutrient loading. Raising ditchwater level was an effective measure to diminish GHG emission and subsidence. Submerged drains enhanced subsurface irrigation greatly and as a result decreased subsidence and GHG emission considerably. For nutrient loading of surface waters the optimal drain depth was around 50-60 cm below soil surface.

P recipitation has long been recognized as a critical, active agent of soil formation (e.g., , Amundson et aI., 2004) with the caveat that actual pedogenesis is driven by the internal behavior of water, not precipitation per se Nordt et aI., 2006). Even small differences in water behavior can significantly alter morphological properties such as redoximorphic features, thickness of epipedons, expression of subsurface horizons,

RESUMEN Alrededor del mundo existen numerosos paisajes con presencia de horizontes petrocalcicos, como en el caso de la llanura Pampeana en Sudamerica. En muchos casos, estos horizontes constituyen una barrera fisica al flujo de agua, e incluso un reservorio de agua para consumo de las plantas. La llanura Pampeana es uno de los paisajes economicamente mas productivos de Argentina, y tal como en otras regiones que naturalmente estuvieron cubiertas con pastizales, estos han sido reemplazados por otros usos.  En muchos casos, estos cambios en el uso del suelo han modificado los flujos hidricos y de solutos de estos sistemas, y el ejemplo mas drastico es el de la forestacion por su gran consumo de agua y la toma selectiva de solutos. Sin embargo, el impacto de esta practica sobre suelos con presencia de horizontes petrocalcicos no ha sido suficientemente estudiado. Dentro de esta region se ha monitoreado variables hidrologicas de un conjunto parcelas de pastizal y forestacion apareadas,...

Grasslands are extensively distributed in flatland areas around the world, such as the Pampas in South America. It is one of the most economically productive landscapes and, as in other regions, they are being replaced by forests at increasing rates. Soil salinization emerges as a negative consequence associated with water deficit and forest groundwater consumption (∼250–500 mm/yr, in this region). An assessment of forest groundwater consumption is crucial for risk evaluation of soil salinization on flatland environments. For this aim, numerical modeling based on physical/biological processes and atmospheric boundary conditions was successfully applied in monitored grassland and afforested plots. Modeling results suggested a partial hydraulic disconnection between forest and phreatic aquifer due to the presence of petrocalcic horizons. Forest transpiration estimates were approximately 13% of total groundwater usage. Forest water consumption was then restricted to that soil portions ...

and older forest floors had more Pb, reflecting the duration of the exposure to deposition . Because of the affinity of organic matter for lead, atmospheric Forest floors were observed to accumulate Pb over loadings of this pollutant have been strongly retained in the forest floor. With the regulation of Pb emissions, loadings have decreased. time from the 1960s to the 1970s. White pine (Pinus We measured changes in Pb in forest floor horizons at a variety of strobus L.) stands in central Massachusetts had nearly northern hardwood sites in New Hampshire from the late 1970s to doubled the Pb content of the forest floor between 1962 the 1990s. In all seven of the sites in which horizons were distinguished and 1978 (Siccama and Smith, 1980). In northern hardwithin the forest floor, Pb was found to be declining in the upper wood and boreal forest at Camels Hump, VT, Pb con-(Oie) horizon, but not in the underlying Oa and A horizons. At the centrations about doubled between 1966 and 1977 Hubbard Brook Experimental Forest (HBEF), this loss from the Oie . In both studies, the majority of resulted in a 36% loss of Pb from the forest floor as a whole between the Pb deposited from the atmosphere over the mea-1976 and 1997 (p Ͻ 0.001). In contrast, in six stands in the Bartlett sured interval was retained in the forest floor (Siccama Experimental Forest (BEF), losses of Pb averaging Ͼ50% from the

The pink clays from the Tagus basin, Spain, were characterized by X-ray difraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Chemical data were obtained by plasma emission spectroscopy and analytical electron microscopy (AEM), and specific surface and cation-exchange capacity were measured also. The data indicate that these pink clays are primarily stevensite. This Mg-rich smectite is characterized by poor crystallinity, a high degree of structural disorder, trioctahedral character (pure magnesian), a very low cation-exchange capacity, a very small crystal size (which generates an abnormally high specific surface area), and a deficiency of octahedral cations. On the basis of the very small crystal size, a large number of edge dislocations, the lack of periodicity (turbostratic) in the structure, and a cellular (spherical) texture observed by TEM, we consider this occurrence to be an early stage of crystallization. Unlike other precursor clay materials described in the literature, this clay is not an alteration of volcanic ash, but it was generated by precípitation from a Si-and Mg-saturated medium.

Modern dusts across southwestern United States deserts are compositionally similar to dust‐rich Av soil horizons (depths of 0–0.5 cm and 1–4 cm at 35 sites) for common crustal elements but distinctly different for some trace elements. Chemical compositions and magnetic properties of the soil samples are similar among sites relative to dust sources, geographic areas, and lithologic substrates. Exceptions are Li, U, and W, enriched in Owens Valley, California, and Mg and Sr, enriched in soils formed on calcareous fan gravel in southeast Nevada. The Av horizons are dominated by dust and reflect limited mixing with substrate sediments. Modern dust samples are also similar across the region, except that Owens Valley dusts are higher in Mg, Ba, and Li and dusts both there and at sites to the north on volcanic substrates are higher in Sb and W. Thus, dust and Av horizons consist of contributions from many different sources that are well mixed before deposition. Modern dusts contain signifi...

Humusica 1, article 4 is strongly related to Humusica 1, article 8, where a lot of photographs illustrate pedofauna and associated droppings. The presented terms and diagnostic horizons are conceived for understanding the soil functioning. They allow to classify the soil with the morpho-functional key illustrated in Humusica 1, article 5. † Corresponding author.

In Germany, the systematics of humus forms has been developed, which is mainly based on morphological characteristics and has been proven via detailed long-term observation. The humus form systematics presented here is an update based on a new approach, clarifying the hierarchical structure into divisions, classes, types, and subtypes. New diagnostic horizons and transition horizons are introduced, uniquely characterising types and subtypes. This paper holds that the humus form is not only a product of decomposition, humification, and bioturbation but also serves as habitat for soil organisms. The processes and the habitat are shaped by soil-forming factors with the main factor being soil water conditions. Thus, on the first level of systematics, aeromorphic and aero-hydromorphic as well as hydromorphic humus forms are differentiated. Many different features of the organic layers and the mineral topsoil can be observed in forests, open grasslands, the mountain zone above the tree li...

Humusica 1, article 4 is strongly related to Humusica 1, article 8, where a lot of photographs illustrate pedofauna and associated droppings. The presented terms and diagnostic horizons are conceived for understanding the soil functioning. They allow to classify the soil with the morpho-functional key illustrated in Humusica 1, article 5. † Corresponding author.

Appropriate land use decisions are vital to achieve optimum productivity of the land and ensure environmental sustainability. Physical land suitability was carried out in Abobo area, western Ethiopia, following the FAO methodology for the determination of length of growing period and maximum limitation method for suitability classification. The result of the study revealed that the climate of the study area is moderately suitable (S2) for the considered varieties of cotton, maize and sorghum, whereas it is marginally suitable (S3) for upland rice. Considering soil and landscape suitability, the most limiting factors were soil depth, wetness, and soil fertility, mostly nitrogen. Based on the FAO model, the potential yields of cotton, maize, upland rice and sorghum were 2,645, 6,409, 4,774 and 4,194 kg ha, respectively. However, yield reductions of 7.32 to 12.09% and 6.01 to 11.16% were observed in simulated rainfed yield for maize and upland rice, respectively, as compared with their...

Deep red soils, combining characteristics of highly weathered materials together with a significant degree of clay illuviation and with stony horizons close to the saprolite, are found in the Province of Misiones, northeastern Argentina. Two basic types of stony horizons have been found, which with the fine-grained material above are together considered autochthonous. The first one is a ''ferruginous nodular horizon'', composed mainly of in situ goethitic nodules of gravel size resulting from weathering and glaebulization processes of basalt. The second are ''siliceous horizons'' which are also in situ, derived from pre-existing quartz veins within the basalt. In contrast, different analytical evidences, particularly the vertical and geographical variations in the SOM-stable carbon isotope ratios and the mineralogical composition of fine and coarse fractions, suggest that these red subtropical soils are polygenetic, being the result of a twofold process linked to paleoecological fluctuations. In the framework of these results, different interpretations about the origin of these soils and their parent materials, and particularly the ''tropical loess'' theory, are discussed.

Description du sujet. Ce travail présente et analyse l'évolution de la conductivité hydraulique des surfaces cultivées et en jachère des formations pédologiques sablo-limoneuses couvrant les altérites du socle cristallin de l'Ouest du Niger. Le travail est mené en des emplacements choisis pour leur représentativité dans la zone sahélienne cultivée. Objectifs. Il vise à faire ressortir l'effet des pratiques culturales, sarclage humide, sarclage sec, sur cette évolution et leurs conséquences sur l'infiltrabilité du sol et le ruissellement. Méthode. L'approche utilisée consiste à étudier l'infiltration sous condition de faible succion grâce à un dispositif constitué d'un infiltromètre et de deux minitensiomètres dans le cadre d'un écoulement monodimensionnel. Résultats. Les mesures, effectuées en suivant le cumul de pluie reçue, ont permis de déterminer et quantifier (i) l'effet du sarclage, (ii) celui de l'humidité préalable du sol au moment du sarclage et (iii) celui de la mise en jachère sur l'évolution de la conductivité hydraulique. La valeur de la conductivité hydraulique en surface s'avère toujours inférieure à celle du sol sous-jacent. La conductivité de la jachère est stable autour de 20 mm. h-1. Celle des zones cultivées, très élevée (120 mm. h-1) après sarclage humide retrouve la valeur mesurée en jachère après 70 mm de pluie et devient même moitié moindre après 230 mm de pluie. Le sarclage en conditions sèches est peu performant, à la fois en termes de conductivité et en termes de persistance de son effet. Conclusions. On en déduit que l'effet bénéfique du sarclage n'est que d'assez courte durée et l'opération devrait être renouvelée après 100 mm de pluie reçue. Mots-clés. Sarclage, jachère, travail du sol, croûtes du sol, conductivité hydraulique, Niger. Evolution of the hydraulic conductivity of a cultivated sandy soil in West Niger Description of the subject. The present study aims to present and analyze the evolution of the hydraulic conductivity of soils in cultivated and fallow areas in the loamy-sand superficial soils within the granitic basement region of West Niger. To this end, experimental plots considered representative of the area were chosen in the Sahelian cultivated area. Objectives. Our objective was to evidence the effect of cultural practices and of both wet hoeing and dry hoeing on this evolution and their consequences in terms of soil infiltrability and runoff. Method. A tension disc infiltrometer was used together with a pair of minitensiometers in one-dimensional flow geometry. Results. Measurements were carried out and variations in total rainfall were calculated, allowing us to determine and quantify the effects of the following on the evolution of conductivity: (i) hoeing, (ii) the level of soil moisture prior to this operation and (iii) the lack of cultivation in fallow areas. Hydraulic conductivity was consistently found to be minimal at the surface. Conductivity in the fallow field was stable at 20 mm. h-1. In the cultivated zones, conductivity was very high (120 mm. h-1) after hoeing in wet conditions, decreasing to the fallow value after 70 mm of rain and even down to half of this value after 230 mm of rain. Hoeing in dry conditions showed poor efficiency, both in terms of conductivity and the duration of the effect. Conclusions. The benefits of hoeing were found to be only short-lived, with the task needing to be repeated after 100 mm of rain.

Soils play a central role in global biogeochemical cycles and host plants and invertebrates whose engineering activities mainly occur in the upper soil layers, the so-called humipedon. This latter is the critical zone where most chemical, physical, and biological ecosystem processes arise. This chapter overviews the main definitions and concepts (diagnostic horizon, humus system, humus form) and functional approaches to humipedon intimately linked to ecosystem engineers, mainly plant roots and earthworms. Biological activities are decisive in integrating organic matter and forming soil aggregates and galleries. We highlight the relevance of studying humus forms based on field observations in various environments (grasslands, forests, mountains, floodplains) and pioneer ecosystems and underline that more research is needed on the role played by earthworms in the evolution of terrestrial biomes. 1 Exploring the Underground The world's population reached a record eight billion people on 15 November 2022, according to the Department of Economic and Social Affairs of the United Nations (2022). Human population growth impacts the Earth's system in various ways, including the extraction of natural resources such as fossil fuels, minerals, trees, water and wildlife. Moreover, more than half of the world's population now lives in urban areas (Ritchie et al. 2024), and urbanisation is still in expansion.

Physico-biochemical processes occurring in soil are difficult to predict because the knowledge of local soil properties such as soil moisture and temperature is often limited. Therefore, soil moisture and temperature regime classes are necessary for US soil taxonomy and other classification systems. The goal of this study is to develop a modeling tool to predict soil moisture and temperature at multiple soil horizons and to code the Keys to Soil Taxonomy in a Soil Moisture and Temperature Regime Classification (SMTRC) module for automatic identification of soil moisture and temperature regimes. The Environmental Policy Integrated Climate (EPIC) model was extended as the EPIC-SMTRC tool for this purpose. Field data from the Soil Climate Analysis Network (SCAN) sites and the Wye farm site in Maryland for validation of soil moisture and temperature predictions. Results indicate that predicted daily soil temperatures are in close agreement with observed values with R 2 values ranging from 0.73 to 0.98 and Nash-Sutcliffe efficiency (NSE) from 0.50 to 0.96. Predicted soil moisture by EPIC-SMTRC captured observed trends reasonably well. Testing results at the Wye farm indicate that the predicted daily values of water content are satisfactory, with R 2 values ranges from 0.66 to 0.88 and NSE from 0.51 to 0.84. The EPIC-SMTRC tool demonstrated the ability to automate the identification of the soil moisture and temperature regimes as currently defined in the US soil taxonomy and can be used to classify soils and to be utilized for other sites.

In soil survey, there is a need to estimate bulk density (at-33 kPa matric potential, D b,33) for the range of soils that occur in the United States. The objectives of this study were to develop a bulk density model using the k-nearest neighbor (k-NN) approach and validate this model against an independent dataset. The nearest-neighbor approach passively stores the development (or reference) dataset until the time of application, and then the dataset is searched for the 10 (k) most similar soils to that of the target soil, based on selected attributes (e.g., organic C, total sand, silt, and clay). Reference datasets were developed from the National Cooperative Soil Survey characterization database in Lincoln, NE. The model uses a decision tree to determine which reference dataset and attributes are to be used to predict D b,33. Validation results with an independent dataset showed a small, but significant bias or systematic error (ME =-0.0215 g cm-3). However, the overall prediction error (or RMSE) of 0.108 g cm-3 is smaller than most reported literature values. The k-NN model for estimating bulk density is suggested to provide an efficient and reasonably accurate tool for use in soil survey for a wide range of soils.

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Two soil profiles containing multiple buried soils were described and sampled to determine the relative impact of past alluvial sedimentation and melanization on buried A horizon formation. Total organic carbon content (TOC), particle size analysis, and soil morphology were combined to detect buried soils and determine the influence of melanization, cumulization, sedimentation, and welding on A horizon formation. The incorporation of phytolith content supported the interpretations made by combining TOC, soil morphology, and clayfree sand content in all but one of the seven surface and buried soils investigated. Soils predominantly formed by melanization, but two thick and dark buried A horizons formed by cumulization during multiple small flood events. Large flood events, as identified by medium to thick beds, were common throughout the soil profiles, marked the top of the buried A horizons, and ended periods of soil formation. Phytolith content versus depth mirrored changes in TOC and can be used as a proxy for soil stabilization by plants. The addition of diatom identification to grass-type phytolith analysis assisted in the recognition of a period of excess wetness during soil formation for one buried soil.

The <2 mm fraction of 605 samples of the C-horizon of podzols collected from an area of 188,000 km 2 in the European Arctic was analysed for more than 40 chemical elements. The results were used to construct geochemical maps which showed clear regional distribution patterns, notwithstanding the very low sample density of 1 site per 300 km 2. Some of these patterns ®t established lithological boundaries. Others ®t lineament structures in the area and underline the relative importance of certain tectonic directions some of which have not yet been delineated on existing geological maps. Some mark large-scale hydrothermal events and related alteration. Finally, some are connected with prominent, known ore deposits occurring in the area. However, several large deposits and even famous metallogenic provinces (Fe, Ni/Cu) are hardly, or not at all, re¯ected in the regional geochemical maps. In their present de®nitions geochemical provinces and metallogenic provinces are thus not necessarily related. Special geochemical features can occur at very dierent scales. The term geochemical province is so imprecise in terms of processes leading to regional-scale geochemical features that it should be avoided. Low-density geochemistry can be used to aid the interpretation of the geological evolution of large regions. It can also be used to ®nd prospective areas within such regions.

I\s part of USDA's effort to support the Afghanistan military M. campaign, Operation Enduring Freedom, the Natural Resources Conservation Service-National Soil Survey Laboratory (NRCS-NSSL), working in partnership with the USDA Foreign Agricultural Service (FAS) developed an agreement to sample soils; teach local nationals about soil and water conservation, soil sampling, and techniques for describing a soil; and also promote capacity building of the agricultural sector in Afghanistan. This article will relate the experience from the point of view of the senior author, Bruce Dubee, as an agricultural advisor and the experience of sampling soils in Afghanistan. Afghanistan? Why during a war? The answer is complicated, just like everything else in Afghanistan. Most Americans don't realize it, but winning the war on terrorism in Afghanistan is much more than fighting with guns and bombs. Security operations may dominate the news from Afghanistan, but I believe the fighting includes another very different war, a battle against ignorance and poverty, in a very dangerous region, under conditions that most of us would consider shocking. Winning

I\s part of USDA's effort to support the Afghanistan military M. campaign, Operation Enduring Freedom, the Natural Resources Conservation Service-National Soil Survey Laboratory (NRCS-NSSL), working in partnership with the USDA Foreign Agricultural Service (FAS) developed an agreement to sample soils; teach local nationals about soil and water conservation, soil sampling, and techniques for describing a soil; and also promote capacity building of the agricultural sector in Afghanistan. This article will relate the experience from the point of view of the senior author, Bruce Dubee, as an agricultural advisor and the experience of sampling soils in Afghanistan. Afghanistan? Why during a war? The answer is complicated, just like everything else in Afghanistan. Most Americans don't realize it, but winning the war on terrorism in Afghanistan is much more than fighting with guns and bombs. Security operations may dominate the news from Afghanistan, but I believe the fighting includes another very different war, a battle against ignorance and poverty, in a very dangerous region, under conditions that most of us would consider shocking. Winning

The goal of this project was to develop a method to measure the total gaseous mercury (TGM) concentrations in unsaturated soils. Existing methods did not allow for easy replication, were costly, and were more suited for other gases, such as CO 2 , that do not react with collection surfaces. To overcome these problems, we developed a method that simultaneously collects up to ten soil pore air samples. We used a single mass flow controller, one pump, and two banks of rotameters to draw soil air out of the ground at 25 smLmin −1 onto gold-coated quartz traps. Analysis of the gold traps was performed with a Tekran 2500 CVAFS mercury detector. The system was field tested at the Piney Reservoir Ambient Air Monitoring Station in western Maryland. Our system was relatively precise and accurate. For example, replicate TGM concentrations differed by less than 25% and recovery of known amounts of mercury were greater than 95%. Field measurements showed that the maximum soil pore air TGM concentrations, between 3 and 4 ngm −3 , occurred at the Oe-A soil horizon interface. At all other depths, the total mercury concentrations were lower than the ambient air concentrations of 1.8 ngm −3. We believe our new method can be used to precisely and accurately measure the TGM concentrations in unsaturated soils at multiple locations simultaneously.

The historic loss of wetlands in the USA along with the recognition that they perform hydrologic, biogeochemical, and habitat functions has resulted in regulation at Federal, state, and local levels (Dahl, 1990; Natl. Res. Council, 1995). Regulatory methods generally require the onsite evaluation of soils, vegetation, and hydrology at potential jurisdictional wetland sites (Environ. Lab., 1987). Methods were established for hydric soil identification by the Corps of Engineers Wetlands Delineation Manual (Environ. Lab., 1987) and further improved by the USDA-Natural Resources Conservation Service (NRCS) in cooperation with the National Technical Committee for Hydric Soils (NTCHS) (USDA-NRCS, 1996). The goal of the work reported here was to take hydric soil identification one step further during routine wetland assessments by providing a field key for the identification of hydric soils to the series level in Illinois. Hydric series were selected from the Illinois Hydric Soils List, a subset of Hydric Soils of the United States (USDA-NRCS,1991; Fed. Reg., 1996), and entered into a database along with several of their specific properties. Series were sorted based on morphological and landscape properties to produce a field key that differentiates 124 soils to the series level. In making the key, differences between county lists and the Illinois Hydric Soils listS were discovered and also are briefly discussed. Finally, the key database also was used to summarize predominant hydric soil types and parent materials in Illinois. Baekground The contiguous 48 states have lost 54% of an initial 221 million acres of wetlands between the 1780s and 1980s to agriculture, mining, forestry, oil and gas production, water resource development, and urbanization (Office of Wetlands Protection, 1989; Dahl, 1990). Analysis of hydric soil abundance in Illinois estimated a decline in wetlands from 8 261600 acres (23.1% of the land surface) in pre-settlement times to 917765 acres (2.6% of the land surface) by the 1980s (Havera et aI., 1994). This 90% decrease in wetland abundance resulted primarily from conversion of lands for agriculture. Legislation has been enacted to slow or reverse this loss of wetland acreage and associated functions. Examples of Federal legislation regulating wetlands (as cited by Hubbell et aI., 1995) include Section 404 of the Clean Water Act of 1972 (CWA), the Rivers and Harbors Act, and the Swampbuster Provisions of the Food, Agriculture, Conservation, and Trade Act. In Illinois, direct regulation of wetlands occurs through the Interagency Wetlands Policy Act of 1989. Implementation of these

The percolation test (also called the perc test) is widely used as the standard method for assessing the suitability of a soil for onsite wastewater disposal. Due to variations within the method itself as well as the plethora of factors affecting the flow of water out a cylindrical hole (Philip, 1985), the percolation test produces highly variable results (

Tranyilvanian Plain is considered as an area with a low capacity to adapt to climate changes, monitoring the climate and implementing the adaption measures being essential for the development of certain durable agricultural technologies. The monitoring and variability of climate elements were achieved during 2008 (March) 2014, through a network of 10 HOBO stations which store soil temperature data electronically (at 10, 30, 50 cm deep) and air (at 1 m hight), soil moisture (at 10 cm depth) and are equipped with rain gauges. The purpose of the paper is to establish the tendency in the evolution of the soil thermal and hydric regime, to predict and identify the climate tendencies from the Transylvanian Plain. The thermal regime of soils in this area is mesic, the differences between the annual averages of summer temperatures and the average of winter temperatures 50 cm deep in the soil are ranging between 12.8120.01°C. The evolution of temperatures at the soil level during 2008-2014 i...

Earth mat provides a common ground for the electrical equipment as well all the metallic structures in the substation. The personnel safety and protection of equipment depends solely upon the effective Grounding system and hence its design becomes a critical aspect in substation. When there is an Earth Fault, it gives rise to potential gradient (GPR) within and around the substation. This GPR has to be restricted to a value which is not detrimental to the surrounding personnel and equipment. The GPR depends on various factors, one of which is the type of soil in substation. In this paper, design of the grounding grid for rectangular configuration is done for a 2 layer soil and analysis is done by ETAP software. The methodology adopted for designing is based on IEEE Std. 80-2013.

Soils with low organic matter and modest biological activity exhibit a reduced capacity to produce goods and services. The use of biochar as a soil amendment has been suggested as a way to increase soil productivity thanks to its physical and chemical characteristics. These properties lead to its possible use as a structural support and a habitat for microorganisms. This study investigated the role of biochar, produced from olive mill pomace at the Mediterranean Agronomic Institute of Bari by a slow pyrolysis process, as a carrier of two microbial communities extracted from a fertile soil and a commercial compost. This study aims to highlight the relationship between the physical structure of biochar and the potential microbial community and to evaluate the use of charged biochar as a carrier of microflora. The inoculation of agricultural soil with biochar seems to have no effect on the total aerobic heterotrophic microflora evaluated with the plate count method. Nevertheless, scanning electron microscope (SEM) images show the presence of biofilm, thus suggesting an early stage of colonization. Despite the short time of incubation of microbial charged biochar in the studied soil, the microbial biomass C and N increased, suggesting a beneficial effect of this amendment.

Sandy soils containing textural bands or lamellae can be difficult to map. The lamellae vary in amount, thickness, and depth over relatively short distances. Accordingly, within some map units, the Bt horizon can vary from weakly expressed with few, thin discontinuous lamellae to strongly expressed with a continuous argillic horizon. In southwest Michigan, consociations of Psammentic Hapludalfs contain inclusions of Alfic Udipsamments, Arenic Hapludalfs, and Glossoboric Hapludalfs. These soils have different waterholding capacities and water flow characteristics. Some users of soil information are requesting that these soils be separated in high-intensity surveys. Ground-penetrating radar (GPR) has been used successfully to determine depth to bedrock

Alternative and more appropriate methods are needed for the collection, assessment, and presentation of soil data. In many instances, the spatial distribution of soils and soil properties has not been adequately described or displayed for the users of soil information. Advanced field techniques and improved computer-graphic methods can be used to collect, summarize, and display information on the spatial distribution of soils within and among map units. Some soil surveys have obtained information on the composition of map units and the spatial distribution of soils and soil properties from ground-penetrating radar (GPR) and electromagnetic induction (EM) techniques. Computer graphic techniques have been used to analyze or display this information. Geophysical techniques were used by the soil survey staff in Reno County, Kansas, to provide information on lamellae, paleosols, water tables, and taxonomic composition of selected map units. This article documents the use of EM and computer graphic techniques to prepare interpretive maps of a small study site in an area of sand dunes. In this cursory study, EM and computer graphic techniques were used to assess rates of change in soil properties with distance, characterize soil boundaries within a soil delineation, and infer soil types. Electromagnetic induction is a noninvasive geophysical technique which uses electromagnetic energy to measure the apparent conductivity of earthen materials. Apparent conductivity is a weighted average measurement for a column of earthen materials to a specified observational depth (Greenhouse & Slaine, 1983). Variations in apparent conductivity are produced by changes in the electrical conductivity of soils and other earthen materials. The electrical con

A 9-by 10-m grid with observation sites 1 m apart was constructed on a mapped area of Sapelo (sandy, siliceous, thermic Ultic Haplaquods) soils to determine microvariability of depths to spodic and argillic horizons in a representative Atlantic Coast Flatwoods area. Ground-penetrating radar (GPR) was compared with conventional field techniques to obtain the necessary data. Results indicated that the entire study area had a spodic horizon at an acceptable depth for the Sapelo series, but only 79% of the study area had an argillic horizon below the necessary 1-m depth. Computer-generated diagrams and maps can be used to select the most representative pedon for sampling, to display the variability of diagnostic subsurface horizons and surface elevation, and to characterize the composition of map units. Field time was reduced substantially when the GPR was used to obtain the necessary field data compared with conventional soil survey methods.

During the past 6 yr, the USDA-SCS has been exploring the potential of using ground-penetrating radar (GPR) to assist and to accelerate soil survey operations. With the Food Security Act of 1985, the use of GPR techniques is being encouraged to increase productivity, the amount and accuracy of our soil data, and the confidence that we place in our interpretations. Advantages of the GPR system are: its speed of operation, capacity to produce large quantities of continuous subsurface data, and high resolution. Compared with conventional auger or borehole methods, GPR techniques provide continuous spatial records of the subsurface, greater areal coverage per unit sampled, and higher levels of confidence in site evaluations. Ground-penetrating radar surveys are faster, more economical, less likely to miss subsurface features, nondestructive, and can be used in sensitive areas. Within USDA-SCS, the GPR has been used as a rapid reconnaissance, investigatory, and quality control tool. The principal use of GPR has been to estimate the composition and to assess the variability of soils and soil features within soil map units that have been delineated with traditional survey procedures. In many states, GPR has increased the efficiency of sampling and the quality and quantity of transect data. Ground-penetrating radar techniques have been used sucessfully in Florida to update soil surveys. In a comparative study with conventional methods, on Coastal Plain soils in Florida, the GPR decreased the average cost per transect by 700/0 while increasing productivity per man-hour by 210%. Studies continue to demonstrate the wide application for GPR techniques within USDA-SCS. Archaeologist, agronomists, engineers, geologists, and hydrologists have used the GPR to: locate buried cables, pipes, foundations, and other artifacts; to measure traffic and plow pan development and expression; to locate natural induced hazards including cavities, soil piping, voids under and within earthen structures, and areas of general subsidence; to detect buried hazardous materials, leaks in pipes, and areas of contaminant intrusion; to map bedrock surfaces, geologic structure, and jointing patterns; to profile geomorphic or stratigraphic features, river or lake bottoms, and peat; and to determine the thickness of earthen strata and the rates of sedimentation. The USDA-SCS has evaluated the GPR's performance on a wide variety of soils in diverse geographic locations. From Maine to California and from Washington to Florida, the GPR system has been field tested in 37 states on innumerable soils and site conditions. Not all areas are suited to the use of GPR techniques. The probing depth and resolution of the GPR are, to a large degree, determined by the electrical conductivity of earthen materials. Soils or earthen materials having high conductivities rapidly dissipate the radar's energy and restrict its probing depth. The principal factors influencing the conductivity of soils are: (i) moisture content, (ii) the amount and type of salts in solution, and (iii) the amount and type of 'Soil specialist (GPR),

Among the reasons for updating soil surveys is the need to extend soil information to greater depths than documented in existing soil survey reports (Brown, 1985). Soil depth classes have not been static, but follow contemporary changes in Soil Taxonomy and series control section concepts (Soil Survey Staff, 1999). In the first edition of the Soil Survey Manual (Soil Survey Staff, 1951), a very deep soil depth class was described as being "rarely required" and having an upper limit "somewhere between 50 and 60 inches" (125-150 cm). By 1993, in response to soil rating criteria that were developed for some urban and engineering intetpretations, the very deep depth class was recognized as being> 150 cm (Robert Engel, USDA-NRCS-NSSC, personal communication). Today, standard soil depth classes are: very shallow (0-25 cm), shallow (0-50 cm), moderately deep (50-100 cm), deep (100-150 cm), and very deep (>150 cm) (Soil Survey Division Staff, 1993). Prior to 1993 and in the absence of a very deep soil depth class, many soils were examined to a depth of only 100 cm. Many soil series formerly recognized as being deep were reclassified as very deep when this latter criterion was established as a standard depth class. While the names of affected soils and map units often remained unchanged, technical guides and interpretations were adjusted to reflect changes in soil depth classifications. As a consequence, in many areas having published soil survey reports, it is uncertain whether soils are deep or very deep. The modernization of these soil surveys requires extensive soil transecting to insure proper classification and intetpretations. A portion ofthe soil survey of McHenry County, North Dakota, is being updated. This county has extensive acreage mapped as Hecla, Maddock, and Ulen soils (DesLauriers, 1990) (Table 1). At the time of mapping these soils were recognized as being deep (> 1 00 cm), although some substratum phases were recognized below 100 cm. However, it was decided that substratum phases could not be consistently mapped, and these soils were all correlated as being members of the deep soil depth class. Today, as all of these soils are recognized as being very deep, it is uncertain which delineation are predominantly deep or very deep and whether additional series or phases are needed to improve intetpretations. Recently, soil scientists in the Northern Great Plains Soil Survey Region (MO 7) evaluated the feasibility of using ground-penetrating radar (GPR) to facilitate and expedite the determination of map unit composition