Soil Profile Descriptions Research Articles

Towards a dynamic soil survey: Identifying and delineating soil horizons in-situ using deep learning

Soil horizons are the manifestation of pedogenesis and contain the basic morphologic indicators of soil formation. Accurate and quantitative tools for delineating soil horizons in-situ can assist soil scientists towards rapid and dynamic soil survey information. The objective of this study was to develop a deep-learning-based, soil-profile-imaging method for identifying and delineating soil master horizons to assist in digital soil descriptions. A total of 160 soil profile images from four soil orders (Alfisols, Entisols, Inceptisols, and Mollisols) were collected from north China in the Inner Mongolia and Liaoning regions. The 160 profile images were amplified to 2400 individual images for model building using data-augmentation procedures. The augmented profile image dataset was divided into training (70%), validation (15%), and test (15%) datasets. The training and validation datasets were imported into a nested, U-net network for model building. The proposed deep-learning (DL) model classified soil profiles into A, B, and C horizons. The mean pixel accuracy of the DL model was 0.86 with the training dataset, 0.82 with the validation dataset, and 0.83 for the test dataset. Results showed that the DL model was judged to be accurate enough for identifying and delineating soil master horizons from profile images in practice. Based on the proposed DL model, a smartphone application was subsequently developed to digitalize the soil profile and assist field evaluation of soil profile horizonation. The smartphone application, for the Android operating system (version 5.0 and greater), featured a response time of < 5 s. This study demonstrated that the proposed DL model and smartphone application could be a simple, fast, and digital tool for quickly identifying and delineating in-situ soil horizons. These tools allow for rapid data collection, which can be used for future artificial intelligence development and application in soil science towards digital soil profile description and dynamic soil survey.

Soil structure and soil moisture dynamics inferred from time-lapse electrical resistivity tomography

The semi-arid sagebrush steppe in the western United States faces pressures from the agriculture industry, recreation use, invasive grasses, and a changing climate. A key to facilitating the healthy management of this ecosystem is understanding the distribution and behavior of soil moisture in the vadose zone in both natural and agricultural settings. Within unsaturated environments, soil moisture is spatially and temporally heterogeneous, and changes in porosity and permeability within arid soils complicate characterization of soil hydrologic properties. Importantly, accumulations of ‘caliche’ or pedogenic calcium carbonate in arid soils can greatly limit permeability; however, observing the role that caliche plays in the hydrologic process is difficult because the installation of in situ instruments disturbs the soils and only provides information at a single point. To investigate vadose zone processes on a broad temporal and spatial scale, we installed a 7x8m2 electrical resistivity tomography (ERT) array at the Reynolds Creek Critical Zone Observatory in southwestern Idaho. Existing soil moisture observations show that infiltration is limited to depths less than 60 cm at this site, as compared to at least 90 cm at other sites in the watershed. To capture the seasonal wetting and drying of the soils, as well as the soils’ response to rainfall events, we monitored the site bi-weekly during the spring, summer, and fall of 2015 and 2016. A time-lapse ERT array was placed adjacent to coaxial impedance dielectric reflectometry (CIDR) probes so that the time-lapse ERT data could be referenced to precise measurements of volumetric water content. In addition to the measurements provided by the ERT array and CIDR probes, soil texture analysis and soil profile descriptions from a near-by soil pit show typical arid soil morphology, with accumulations of clays and calcium carbonate in the B horizon. The resulting ERT inversions show the following soil structure: (1) a high-resistivity top layer corresponding with minor amounts of pedogenic calcium carbonate; (2) a low-resistivity intermediate layer at depths corresponding with substantial accumulations (stage IV) of carbonate; and (3) a high-resistivity deep saprolite. The resistivity of the top layer varies seasonally with changes in precipitation, while the intermediate carbonate soil layer does not. This agrees well with the changes in soil moisture with depth measured by the CIDR probes and suggests that the top of the carbonate soil layer limits infiltration. However vertical structure and cracks within the carbonate soil layer create vertical preferential flow paths; resistivity within these flow paths responds to large precipitation events and seasonal changes in soil moisture. This implies that the preferential flow paths are a conduit for soil moisture flow that is not captured by the CIDR probes. From the combined interpretation of the ERT and CIDR we conclude that soil structure and the presence of calcic soil horizons inhibits soil moisture infiltration during both the summer dry months and the winter wet flux period; however, preferential flow paths provide an important vertical connection between the deep and shallow portions of the critical zone.

Modeling soil texture and residue management effects on conservation agriculture productivity in Nepal

Conservation agriculture (CA) is characterized by zero or minimum tillage, permanent land cover with crop residue or plant growth, and crop rotation. Only a few studies have addressed the impact of soil texture on relative CA:CP productivity, and none have simultaneously evaluated soil texture interactions with optimal residue retention rate. We simulated the interaction effects of soil texture and residue retention on crop yield for CA and conventional practices (CP) for a monsoon-season maize [Zea mays L.] and dry-season wheat [Triticum aestivum L.] double-cropping system in the midhills of Nepal. The simulation used 35 years of historical weather data, fifteen soil profile descriptions representing a range of soil texture classes, and variable rates of residue retention. Crop models were calibrated with field data and simulation results evaluated against measured field data from other published studies. Optimal maize residue retention rate was 60 % and optimal wheat residue retention rate was 10 %, regardless of soil texture. At optimal residue retention, CA maize yielded 0.37 Mg ha−1 less than CP on clayey soils and 0.25 Mg ha−1 less than CP on loam soils, equivalent to 5 % and 4 % yield loss, respectively. However, mean wheat yield was greater with CA than CP for all soil textures, with an average yield increase of 0.17 Mg ha−1, or 18 % increase in wheat yield. The time required for CA to produce equivalent maize yields to CP increased by approximately 1.23 yr per % of soil clay. Possible non-linearities exist in the relationship between soil clay and time-to-equivalent maize yield. Wheat yield was more stable, but maize yield less stable, with CA compared with CP for all soil texture categories.

ENVIRONMENT SENSITIVITY MAPS OF LAND DEGRADATION AND DESRTIFICATION USING MEDULAS MODEL AND REMOTE SENSING IN SHIRQAT CITY/IRAQ

This research of aims to study environment sensitivity of desertification and land degradation using MEDULAS project and remote sensing in AL-Shirqat City/Salahadin/Iraq. A 10 soil pedons were chosen from study area depending on difference in soil preperties, landuse and causes of desertification and degradation as (Salinity, Erosion, Gypsum and vegetation cover). Soil profile description, soil samples and GPS were conducted. The physical (texture) and chemical (CaCO3, CaSO4.2H2O, O.M, EC and pH) properties were determined. The Soil were classified as Torrifluvents in the (P1, P2, P3), Torripsamments in the (P5 and P7), Calcigypsids in the (P6, P8 and P10) and Calcids in the P4. The landsat 8 image at 20sep. 2019 and 19 sep. 2013 were aquired in the spectral indices calculate and spatial maps by using ERDAS 15 and GIS 10.2. The result show contrast in soil propreties as sand, clay, soil gypsum, CaCO3, OM and EC that reflect on Soil Quality Index (SQI) which were (60)% poor quality and (40)% moderate quality degradation. While (19.10) % that moderate quality and 80.90% that poor quality for Vegetation Quality Index. The results show that 0.1% of the study area is classified as C1; 25.35% as C2; 74.55% of the areas as C3. The spectral indices as LAI, SI5, OSAVI were approporiate for monitor of desertification and degradation in study area. Add, spatial change in the spectral indices as NDVI and LAI. The results shown that MEDALUS model is a important model in the areas disposed to desertification and degradation.

Petrological Characterization of Pelites from the Mintom Basin and Their Weathering Mantle

The aim of the present study is to characterize a weathering mantle developed on pelitic rock in the tropical forest region precisely in Mintom (South East Cameroun). This characterization include morphology, physico-chemical and mineralogic analyses. The region is characterize by a hot and wet climate consisting of four seasons of inequal length and intensity. The average temperature is about 24°C and the mean rainfall is about 1633mm/years. The rocks in the area consist of limestone, dolomites and pelites. Fieldwork consist of landscape analysis, geologic prospection and soil profile description. Mineralogical and physico-chemical was carried out on various samples in the laboratory. Morphological results show that the studied profile has a general brownish yellow aspect, with a thickness of about 6m and a silty-clayey texture. Five horizons can be distinguished from top to bottom: a humiferous horizon, a loose yellow set, a yellow horizon bearing quartz fragments and large indurated blocks, a saprolite consisting of a fine and coarse saprolite possessing some pelite relics of variable sizes and a deep red colour just like that of the parent rock. The parent rock is a massive pelite with a reddish colour when wet and a violet colour when dry. It has a powdery feel. Analytically, the soils have an acidic pH (4,0 to 4,2), a high organic matter content (4,8%), a C/N ratio of about 6,76, a cationic exchange capacity of 7,64meq/100g with a saturation rate S/T of about 7. Particle size distribution shows that the silty fraction is dominant (59%), followed by the clayey fraction (30%). The main minerals are kaolinite, quartz, smectites, calcites, dolomites, goethite and hematite.

Geotechnology applied to land classification in areas of the Atlantic Forest in southeastern Brazil

The objective of this study was to classify the lands of a micro-watershed located in the Atlantic forest biome, in a region of rough relief, in the use capacity system using geotechnology resources and indicate uses for the lands according to their suitability. The theoretical basis of the Manual for Utilitarian Survey and Classification of Land in the Use Capacity System with adaptations for areas of rough relief was adopted. The study was carried out from the survey of topographic information to construct the altimetric map of the watershed, followed by the survey of the physical environment, especially water erosion, description of soil profiles and collection of samples. The parameters effective depth, texture, permeability, slope, erosion, fertility, and land use were evaluated. Based on the pedological data and on the use of applied geotechnology, the soil map was created, and the lands of the watershed were classified and mapped in the use capacity system. After interpretation of the survey products, it was verified that in rough relief, slope is the predominant factor to determine the classes of land use, as it outweighs the other parameters evaluated. Land classification land with the use capacity system promotes optimization in the use of areas with agricultural areas and preservation of those destined for conservation.

Characterization and Classification of Soils of Zamra Irrigation Scheme, Northeastern Ethiopia

Understanding soil types of a given area is an important prerequisite to design optimum management strategies such as irrigation water management. The study was thus conducted on characterization and classification of Zamra irrigation scheme in Abergelle district of Amhara Region, which has an area of 196.16 ha. For this study, 53 auger observations, four profile pits, extensive visual observations, reconnaissance survey, and descriptions of soil profiles and laboratory analysis were used to study the morphological and physicochemical properties of the soils of the scheme. Twelve disturbed and undisturbed soil samples were collected from all profiles of each genetic horizon for laboratory analysis. The soils of the study area were identified based on Food and Agricultural Organization of the United Nations/World Reference Base for Soil Resources (FAO/WRB) 2015. The results revealed that the textural classes of all profiles of the study site ranged from sandy clay loam to sandy loam. The chemical properties of the soil in terms of total nitrogen, organic matter, and available phosphorus were in the very low and low categories as per the criteria developed by Tekalign and Olsen, respectively, whereas exchangeable bases (Ca, Mg, K, and Na), cation exchange capacity, and extractable micronutrients (Fe, Mn, Zn, and Cu) were medium to high. Based on morphological, physical, and chemical analyses, the soils were classified as Leptic Regosols (Eutric, Loamic; 21.99% of the area), Vertic Cambisols (Hypereutric; 17.87%), Haplic Regosols (Eutric; 36.69%), and Rhodic Nitisols (Eutric; 23.44%). Therefore, management techniques that enhance soil fertility (including crop rotations, manuring, fallow periods, proper management of crop residues, and leguminous cover crops) and water-saving technologies suitable to the terrain of the area are the best options to enhance land productivity in the area.

Modern state of irrigated soils at the south of the Volga upland

The goal is to assess the impact of 50-year irrigation by sprinkling on soil processes occurring in the light-chestnut soils (Luvic Kastanozem (Loamic, Aric, Protosodic, Bathysalic)) of the southern slopes of the Volga upland at the Volga-Don interfluve (FSUE “Oroshaemoe”, the Volgograd region) with deep ground water. Water for irrigation is supplied from the Varvarovsky reservoir of the Volga-Don Canal system. It is characterized by a total dissolved salts of about 1 g/l, a bicarbonate-chloride-sulfate compositionwith an increased sodium content. Detailed morphological description of soil profiles, granulometric composition, content of soluble salts in soils and sediments of the vadoze zone up to the depth of 3.5 m, dynamics of salts in the layer of 0-50 cm for 2011-2019 are presented. Until the autumn of 2015, the studied soils were deep saline, being no saline in the layer of 0-100 cm. In recent years, a weak salinity degree of soda-chloride sodium chemistry has been observed in the 0-50 cm layer as a result of gradual accumulation of irrigation water salts during irrigation organized according to water consumption of agricultural crops. Irrigated soils have acquired a complex of signs of secondary salinity: (1) the presence of light accumulations of sandy and silt mineral grains in the arable horizon, resulting from the destructive effect of irrigation water drops during sprinkling; (2) toxic alkalinity associated with sodium (residual sodium carbonate), according to water extraction 1 : 5 (soil : water), in the horizons from the depth of 10-20 to 60100 cm; (3) abundant humus-clay cutans on the lateral side faces of prismatic structural units in the undisturbed part of the soil profile from 30 to 100 cm.

Developing scoring functions to assess soil quality at a regional scale in rangelands of SW Spain

The drawing of maps of soil quality at a large scale is increasingly being more useful to land planners and stakeholders. Nevertheless, it involves different methodological steps from the description of soil profiles in the field until the regional mapping of integrative soil quality index (IQI) values. The development of proper scoring functions is a paramount task for the calculation of these IQI values since every parameter needs to be standardized accordingly and weighting factors are usually estimated by [...]

Assessment and Spatial Analysis of Sensitivity to Desertification in Wadi El Natrun, Northwestern Egypt using MEDLAUS model

Land degradation is a global environmental issue, given the various negative impact on socio-economic and ecological implications. It leads to reduced production capacity in addition to soil erosion, physical /chemical /biological /economic land deterioration, and long-term loss (or degradation) of vegetation. When a severe deterioration in drought areas called the process of desertification i.e. arid, dry sub-humid and semi-arid areas. Desertification processes reduces the productivity of the soil and as a result effect on food stocks. The main objective of this study is integrating remote sensing data and a geographic information system (GIS) to evaluate the environmental sensitivity for desertification in Wadi El Natrun, Egypt based on the Mediterranean Desertification and Land Use (MEDALUS) approach. The collected soil data; from description of represented soil profiles and analysis of soil samples, in addition to climate, plant cover, and management data were considered for assessing the sensitivity of desertification. The obtained results showed that 10.4 % of Wadi El Natrun area is considered severe sensitivity to desertification as a result of alkalinity and salinity, while the moderately sensitive area occupies approximately 10.93 % of the study area. The low sensitive one exhibits 76.3 %. This area is described by high soil quality because of the study area is one of the new development areas which were not affected by the factors of desertification. It can be concluded that the desert extension of El-Beheira Governorate (i.e. Wadi El Rayan) is one of the areas that possess valuable land resources which should be considered for future land reclamation projects. Similar international studies are recommended to be achieved with the use of multi-criteria GIS modeling (i.e. MEDALUS) which considered all relevant factors in the form of thematic layers for easier implementation and assessments. Present study represents one of the initial attempts to use the MEDALUS model for desertification assessment in the desert extension of El-Beheira Governorate.

Incorporating process-based modeling into digital soil mapping: A case study in the virgin steppe of the Central Russian Upland

In theoretical pedology, the advantage of factor-process-properties models over factor-properties models has been confirmed for the understanding of soil genesis and its changes over time. Currently, the most frequently used model in digital soil mapping (DSM) is the SCORPAN model, which is based on the Dokuchaev-Jenny formula: soil properties are the result of the interactions among soil-forming factors over time. This work aims to incorporate processed-based modeling into DSM and investigate the use of a hydrological model to predict the soil spatial heterogeneity and simulate its spatiotemporal evolution over time in the Central Chernozem Reserve (East European Plain). Our approach, called the Nested Landscape Soil Triad: Factor-Process-Properties, is based on the subordination of soil processes to landscape processes and the nesting of the soil system into the landscape. Landscape processes result in specific landscape properties, which control the direction and intensity of soil-forming processes, and thus control soil properties. We hypothesize that, in the virgin steppe, the result of moisture redistribution via runoff along topography (landscape process) can be expressed quantitatively in the redistributed runoff value (landscape property) that controls the movement of salts within the soil profile (soil-forming processes) and soil taxa (soil properties). We directly linked a result of the landscape process and soil properties due to difficulties in soil-forming processes modeling. We conducted a prediction across the 35 ha study area using a 2.5 m digital elevation model (DEM) and 157 soil profile descriptions as input. The moisture redistribution process was simulated using SIMulated Water Erosion (SIMWE), implemented in open-access software (GRASS GIS). To define the optimal parameter combination for the SIMWE model, we performed multiparameter sensitivity test and optimization. We used Latin Hypercube sampling to generate the 3000 × 6 (the size of sample per number of parameters) parameter set for Monte Carlo ensemble runs within SIMWE. The maximum correspondence between the soil cover pattern and simulated flow depth was achieved with infiltration values of 0–10 mm h−1, Manning’s n of −0.3 to 1.0, water diffusion constant of −0.3 to 0.5, threshold water depth of −0.1 to 0.15 m, diffusion increase constant of −3 to 6, and precipitation excess rate of 60 mm h−1. The runoff redistribution values alone determine the carbonate depth in the soils (64% accuracy) and soil taxa (76% accuracy). Overall, the Nested Landscape Soil Triad: Factor-Process-Properties can explore how soil properties have changed and will change through time and identify areas with risks of soil taxa changes. The contradiction between the selected optimal precipitation excess and current climate prove the polygenetic formation of forest-steppe soils. This approach can be used to inform policymakers and large-scale management to ensure soil security.

Geohidrología de un sector de la marisma de Bahía San Blas

La marisma del arroyo Jabalí forma parte de la Reserva Natural Provincial de Uso Múltiple Bahía San Blas y se encuentra ubicada al sudeste de la provincia de Buenos Aires, Argentina. El objetivo del trabajo es analizar los principales procesos geohidrológicos que regulan la química del agua superficial y subterránea de este humedal y su relación con las características geomorfológicas y pedológicas. Para ello se realizó una caracterización geomorfológica en base a la cual se diseñó una red de monitoreo del agua superficial y subterránea. Se construyeron 14 freatímetros a lo largo de 3 transectas perpendiculares al arroyo y se recolectaron muestras de agua en las que se analizó in situ el pH y la conductividad eléctrica y se determinó en laboratorio el contenido de iones mayoritarios. Los datos fueron analizados mediante gráficos de relaciones iónicas y diagramas de clasificación de aguas. A su vez en cada sector estudiado se efectuaron calicatas para la descripción de los perfiles del suelo y características texturales de los sedimentos superficiales. Los resultados obtenidos muestran que tanto la química del agua del canal Jabalí como la subterránea de la marisma son dominantemente cloruradas sódicas, existiendo un enriquecimiento en el contenido iónico asociado a una mayor distancia con respecto a la boca del canal y una posición topográfica más elevada. El principal proceso que condiciona la química del agua subterránea es la disolución de especies minerales formadas en la superficie de los suelos por evaporación del agua de mar y la posterior incorporación en el acuífero por infiltración. Estos procesos se ven favorecidos por el clima semiárido, la menor recurrencia de inundación por posición topográfica elevada, y por la textura fina de los suelos. A su vez, la oxidación de sulfuros pedogenéticos y la consecuente acidificación del medio son propuestos como otros mecanismos que condicionan la química del agua.

A soil colour map of China

Soil colour can indicate soil physical, chemical and biological properties and processes, and is an important indicator for soil classification, soil quality evaluation and soil management. It varies in both horizontal and vertical dimensions, and thus regional maps of soil colour can reveal spatial patterns of these properties, processes, and indicators. However, although soil regions are sometimes named for their dominant soil colour, it is directly measured only at “point” support, i.e., during soil profile description, whereas it is desirable to know soil colour over the entire soilscape. To achieve this for China we used predictive soil mapping methods to produce soil colour maps (dry and moist colours) at 1 km2grid cell size and over multiple depths from a consistent dataset of approximately 4 600 full profile descriptions taken as part of a national survey to define soil series in Chinese Soil Taxonomy, and a set of environmental covariates covering the national territory. The covariates characterized soil forming factors including climate, parent materials, terrain, vegetation, land surface water and thermal conditions. Soil colour descriptions in the Munsell system were extracted from the genetic horizon descriptions at the selected depths and converted to the sRGB and L*a*b* colour spaces. Dry and moist colour separates were not well-correlated in either space (r<0.76). Random forest models were constructed in both spaces, for dry and moist colours separately. Models in sRGB space were moderately successful (R2≈0.43,RMSE≈26/255) at 5 cm, with success decreasing with depth. Models smoothed the colour space and thus did not predict the more extreme values or chromas, nor the rarer hues. Models in L*a*b* space were less successful. The fitted sRGB models were used to produce predictive maps over all of China. Regional patterns as well as local detail are clearly shown. Solar radiation, wind exposure, regolith thickness, and Landsat TM bands 7 and 5 contributed most to the predictions, followed by elevation, mean annual precipitation, terrain wetness index, air temperature seasonality, precipitation standard deviation and standard deviation of NDVI. These suggest pedological processes acting on the development of soil colours, including weathering of parent materials, oxidation-reduction chemistry and biochemistry of the decomposing of organic matter. This study shows that predictive methods from points using suitable covariates are an alternative to spatial predictions over map units from their representative profiles.

Eliciting experts’ tacit models for the interpretation of soil information, an example from the evaluation of potential benefits from conservation agriculture

We examined a procedure to elicit the tacit models underlying expert opinions on environmental factors that affect the absolute yield benefits expected from the adoption of conservation agriculture (CA) practices in southern Africa. The procedure is based on expert evaluation of the expected improvement in crop yield on adoption of CA in a particular scenario or ‘state’, a state being a specified set of soil conditions captured by a standard soil profile description from a specified agroecological zone (AEZ) of Zambia. Mixed groups of scientists including soil scientists, agronomists, agricultural economists and other environmental scientists, facilitated by experienced senior researchers, were presented with multiple subsets each of three states, and asked to rank the states in each subset with respect to expected yield improvement under CA. The groups of scientists could be divided into two sets. Each set comprised two groups, and the agreement on ranking between groups within each set was larger than would be expected if the ranking were done at random. For both sets of groups the ranking could be modelled with respect to properties of the soil, and the contrast between AEZ. The models revealed two contrasting groups of conceptual assumptions. One group broadly expected larger absolute yield improvements from conservation agriculture in settings where water is most likely to be limiting and the carbon status of the soil is poor. By contrast, the other group expected larger improvements where water was less likely to be limiting. These contrasting views are relevant to current discussions as to whether conservation agriculture, which is promoted as a ‘climate smart’ strategy for cropping, is sufficiently attractive for smallholder producers in conditions where crop production is already challenging, and whether the potential benefits in areas where water availability is not of itself a common limitation should be considered. The elicited models could be translated directly into competing hypotheses to be tested, perhaps in on-farm trials of conservation agriculture practices over contrasting soils in the different AEZ. The method, based on modelling the ranking process, could be of more general interest for the elicitation of expert opinion about complex soil, crop and environmental systems.

Interações pedogeomorfológicas na bacia do rio Preto, Serra do Espinhaço Meridional, sudeste do Brasil

Este trabalho apresenta as relações entre o relevo e os solos da bacia hidrográfica do Rio Preto, região centro-norte do Estado de Minas Gerais, sudeste do Brasil. A bacia do Rio Preto está inserida na Serra do Espinhaço Meridional, feição geomorfológica decorrente da tectônica compressiva atuante sobre rochas quartzíticas durante o Mesoproterozóico. Para o estudo das interações pedogeomorfológicas da área, elaborou-se uma carta morfológica, a partir da restituição de fotografias aéreas nas escalas de 1:40.000 e 1: 60.000. A partir deste produto gráfico, foi feita uma carta exploratória de solos, apoiada por descrições de perfis de solo em campo. Os resultados apontam que a cobertura pedológica da área estudada está dividida em três sistemas de solos, com distribuição muito particular: Laterítico, Podzolizado e Litodependente. No alto curso da bacia predominam os solos do sistema podzolizado e litodependentes, enquanto no médio e baixo cursos, solos do sistema laterítico, com litodependentes nas áreas de declividade mais acentuada. No que tange aos aspectos geomorfológicos, observou-se que as feições do relevo sofrem forte controle estrutural e tectônico, principalmente no alto curso, enquanto no médio e baixo cursos dominam feições ligadas à erosão e estrutura geológica.

MORFOLOGI TANAH INCEPTISOL SETELAH DILAKUKAN PENAMBANGAN UNTUK BAHAN BAKU PEMBUATAN BATU BATA

The purpose of this study was to observe changes in soil morphology after mining for the brick industry. The study was carried out by observing four soil profiles. i.e. (1) soils that have never been mined (control); (2) soils that have been mined and left more than 10 years, (3) soils that have been mined and left for ± 5 years, and (4) soils that have been mined and left between 1-3 years. The method used in this study was the observation of a complete profile (cross-section of soil) which aimed to collect primary data directly through field observations and the description of individual soil horizons. The implementation of this research consisted of three stages, i.e. soil survey, soil profile description, and collection of soil samples from soils that have never been mined and that have been mined for years. Results of this study showed changes in soil morphology after the soils were mined for years, i.e. yellowish-brown colour, granular structure, loose consistency, no rooting zone, and abrupt horizons. The Inceptisol soils that have been mined for brick making materials experienced changes of morphology and soil properties. Further studies on land rehabilitation technique need to be carried out for consideration in restoring post-mining lands.

Impact of a national collegiate soil judging competition on student learning and attitudes

AbstractThe annual National Collegiate Soils Contest (NCSC) has long been anecdotally recognized as a beneficial event for participating students to practice soil profile descriptions and landscape interpretations. The objective of this study was to quantify student learning outcomes and to identify how students’ perspectives shifted over the course of the week‐long 2019 NCSC, which was hosted by California Polytechnic State University in the San Luis Obispo, CA, area. Participants were asked to complete voluntary pre‐ and post‐contest surveys related to attitudes toward soil science and their knowledge of soil profile description and landscape interpretation, measured using a five‐point Likert scale. Open‐ended questions, which allowed free responses, were also included. Eighty‐three participants completed the pre‐contest survey, and 62 students completed the post‐contest survey. Student understanding increased significantly for five of the seven topics pertaining to soil‐judging‐related skills. Most participants had very positive attitudes toward soil science and soil judging, both pre‐ and post‐contest. Very few significant differences occurred between genders and majors. The most common positive comments were related to location‐based learning, whereas negative comments included environmental factors, such as sun and heat, and long days. Overall, participants indicated the contest was a positive and meaningful educational event, especially for location‐based learning.

Pedological Characterization and Suitability Assessment for Cassava Production in Bukoba, Missenyi and Biharamulo Districts, Tanzania

A study was conducted in Bukoba, Missenyi and Biharamulo Districts, Tanzania with the objectives of characterizing, classifying and assessing the suitability of the study area for cassava production. A reconnaissance field survey using transect walks and auger observations was done in the study sites, which were geo-referenced in terms of international coordinates using Global Positioning System. Soil profiles representative of the study sites were excavated and named as MARU-P1, MISSE-P1 and BIHA-P1 for Bukoba, Missenyi and Biharamulo Districts, respectively. Soil profile description and data on the morphological features of the representative soils were collected according to the FAO Guidelines for Soil Description. Disturbed and undisturbed soil samples were collected from genetic soil horizons, processed and analyzed in a soil laboratory. Data on site characteristics, climate, soil morphological features and soil physical and chemical properties were used to classify the soils to the family level of the USDA Soil Taxonomy and to tier-2 of the FAO World Reference Base for Soil Resources. Soil suitability assessment of the experimental sites was done using a simple limitation method based on the FAO Framework for Land Evaluation. The results reveal that Pedons MARU-P1 and BIHA-P1 have similar morphological properties, which are different from pedon MISSE-P1. However, the studied pedons differ in their physical and chemical properties, implying differences in their use and management. The climate of the study sites is semi-humid with <i>Udic</i> soil moisture regime, which is generally favourable for crop production. According to the USDA Soil Taxonomy, pedons MARU-P1 and BIHA-P1 were classified as <i>“Typic Kandiudults”</i>. In addition, according to FAO World Reference Base for Soil Resources, pedons MARU-P1 and BIHA-P1 were classified as <i>“Haplic Ferralic Acrisols”</i> and <i>“Chromic Ferralic Acrisols”</i>, respectively. Pedon MISSE-P1 was classified as <i>“Typic Endoaquolls”</i> according to USDA Soil Taxonomy and as <i>“Fluvic Gleyic Phaeozems”</i> according to FAO World Reference Base for Soil Resources. Pedons MISSE-P1 and BIHA-P1 were both evaluated as marginally suitable while MARU-P1 pedon was evaluated as moderately suitable for cassava production due to soil fertility constraints. We recommended specific soil fertility management strategies in each studied site for optimum cassava yields.

Characterization and Classification of The Soils of Bukuru-Jos, North Central Nigeria

Twelve profile pits were sunk, four in each of the three locations of Bukuru, the study area. Proper soil profile description was done and recorded to obtain field characterization data after which thirty-six soil samples were collected from all the genetic horizons for soil characterization. Bukuru soils showed higher sand fraction (71%) than silt (12%) and clay (17%) at the topsoil but showed increased clay content at the subsoil. While Gyel and Fwarti locations soils were sandy loam, Rabi location soil was sandy clay loam. Soil pH, Organic carbon (Org. C), Total Nitrogen (Total N), and Available phosphorus (Avail. P) were 6.2, 6.3 gkg- 1, 1.9 gkg-1 and 4.82 mgkg-1respectively and were graded low. Exchangeable bases were dominated by Ca2+ and Mg2+. Sodium (Na+), Potassium (K+), Cal- cium (Ca) and Magnesium (Mg) were 0.24 cmolkg-1, 0.06 cmolkg-1, 15.7 cmolkg-1 and 2.60 cmolkg-1 respectively. While Na+ and K+ were graded low, Ca2+ and Mg2+ were graded high. Cation Exchange Capacity (CEC) was 18.82 cmolkg-1, and was graded high. All the soil samples analysed showed high per- centage base saturation (PBS), above 90%. The low values of Org. C, Total N, Na and K and the characteristic sandiness of Bukuru soils in the surface horizon indicated the low fertility status of Bukuru soils. Bukuru soils were classified using the Keys to Soil taxonomy of the USDA as “Typic isothermic kandic us- talfs”. This was correlated to “Lixisols” in the World Reference Base (WRB) of FAO at a higher level and "Rhodic/Chromic" as a principal qualifier. .

Modelling long-term blanket peatland development in eastern Scotland

Abstract. Blanket peatlands constitute a rare ecosystem on a global scale, but blanket peatland is the most important peatland type on the British Isles. Most long-term peatland development models have focussed on peat bogs and high-latitude regions. Here, we present a process-based 2-D hillslope model to simulate long-term blanket peatland development along complex hillslope topographies. To calibrate the model, the peatland architecture was assessed along 56 hillslope transects in the headwaters of the river Dee (633 km2) in eastern Scotland, resulting in a dataset of 866 soil profile descriptions. The application of the calibrated model using local pollen-based land cover and regional climate reconstructions (mean annual temperature and mean monthly precipitation) over the last 12 000 years shows that the Early Holocene peatland development was largely driven by a temperature increase. An increase in woodland cover only has a slight positive effect on the peat growth potential contradicting the hypothesis that blanket peatland developed as a response to deforestation. Both the hillslope measurements and the model simulations demonstrate that the blanket peatland cover in the study area is highly variable both in extent and peat thickness stressing the need for spatially distributed peatland modelling. At the landscape scale, blanket peatlands were an important atmospheric carbon sink during the period 9.5–6 kyr BP. However, during the last 6000 years, the blanket peatlands were in a state of dynamic equilibrium with minor changes in the carbon balance.