Pedological Factors Research Articles

Heavy metal contamination along a soil transect in the vicinity of the iron smelter of Kremikovtzi (Bulgaria)

Based on previous preliminary survey results, elevated heavy metal concentrations of the agricultural soils of the villages of the Kremikovtzi region east of the Bulgarian capital Sofia were attributed to pollution from dusts emitted by the iron smelter in the centre of the region. Additional sampling in a test area indicated that high metal concentrations in this area could also be of geogenic origin. In order to test this hypothesis, we sampled a sequence of 14 soil profiles at increasing distance from the smelter along a 2 km transect through agricultural land outside the metallurgical complex of Kremikovtzi. The transect extended through two different units of soil types: Chromic Luvisols and Alluvial Fluvisols. Samples of the fine earth fraction (< 2 mm grain size) from various depths were analysed for 19 elements by X-ray fluorescence spectroscopy (XRF). Maximum concentrations of the suspected main pollutants were approximately 170 mg/kg As, 185 mg/kg Pb, and 350 mg/kg Zn. Concentration profiles over depth were distinctly different between the two soil units for most elements and in comparison to this difference varied little within each unit. Within the two units there were no trends with distance to the smelter. The concentration profiles did not indicate any substantial contribution from atmospheric deposition. The enrichment of elemental concentrations relative to Zr did not provide sufficiently conclusive evidence to distinguish anthropogenic from geogenic metal sources. While the ratios of zinc, copper and arsenic to zirconium were almost constant, chromium, nickel and molybdenum ratios to zirconium varied between 2- and 5-fold (primarily showing a decrease) with depth in the majority of profiles, indicating gradients in the original deposition of the soil-forming parent material rather than an anthropogenic source. The study illustrates how important it can be in identifying the origin of soil pollution not only to look into areal distribution patterns of suspected contaminants, but also to investigate their depth profiles as well as that of other elements and to account for pedological factors and their variability.

Superficial and subterranean soil erosion in Tabasco, tropical Mexico: Development of a decision tree modeling approach

Tropical countries suffer from a lack of financial resources to monitor and model sources and outcomes of soil degradation and, therefore, a scarcity of data. In this study it was tried to model superficial and subterranean water erosion based on basic environmental variables such as geological formation, soil type or vegetation cover — data which are potentially available even in developing countries. Different forms of water erosion and karst or pseudokarst formations in Tabasco, Southeastern Mexico were estimated. The study region (3500 km 2) consists of plain and hilly areas with an annual precipitation ranging from 2000 to 4000 mm. Main land use form is rangeland. The area is geologically composed of sedimentary rocks, limestone, sandstone and conglomerates. Collecting data by field observations over the entire study area a cartography of different soil loss forms such as rill and gully erosion, mass movement, sinkholes and tunnels was created including field data from available maps of geological formation, soil type, precipitation and former land use 20 years ago. Additionally, data collected in the field such as actual land use, vegetation cover and inclination were added. In the entire study area 1039 sites were affected by soil erosion with 2435 single manifestations of soil erosion. 482 sites were found with one gully each, 57 sites with erosion rills with a total of 416, 392 sites with one mass movement each, 85 sites with sinkholes with a total of 1122, and 23 sites with one tunnel each. Rendzic Leptosols over Oligocene limestone are strongly affected by sinkholes and tunnels in regions with inclinations of less than 5°. This phenomenon is explained by karstic and pseudokarstic formation. Superficial erosion forms are mainly found on rendzic Leptosols over shale sandstone and on eutric or peli-eutric Vertisols on Andesit in areas with inclinations between 5 and 30°. The application of classification trees allowed to successfully predict the occurrence of sinkholes and tunnels (degree of agreement between prediction and observation: very good to excellent). Even in areas with scarce data-bases this could allow for easy identification of high-risk areas. Predictive success of the occurrence of the different forms of superficial soil losses, however, is low. Superficial erosion seems to be mainly caused by more specific pedological factors. Nevertheless, automated induction of classification trees can be a valuable tool for preliminary data analysis and hypothesis generation in areas with lack of local expertise and can guide erosion risk mapping and soil conservation planning.

LOCATION EFFECTS ON OXIDATIVE STABILITY OF CHÉTOUI VIRGIN OLIVE OIL

The effect of growing area on the natural antioxidant and oxidative stability of Chetoui virgin olive oil was studied. Total phenolic content, tocopherol composition, fatty acid composition and oxidative stability were analyzed. The results obtained in this study showed that Chetoui virgin olive oil composition is greatly influenced by growing environment, i.e., mainly by the climatic and pedologic factors. The cumulative rainfall appears to have a major influence on phenolic and o-diphenol content. Among studied samples, Amdoun oil had the highest total phenolic content, which exceeded 700 mg/kg. Moreover, it contained the highest amounts of o-diphenols 286.08 ± 6.74 mg/kg and total tocopherols 405.65 ± 4.17 mg/kg. The amounts of total phenols and o-diphenols showed a good correlation (P ≤ 0.001) with stability while tocopherols showed a very low relation to oxidative stability.

Characterization of Viticultural Terroirs using a Simple Field Model Based on Soil Depth – II. Validation of the Grape Yield and Berry Quality in the Anjou Vineyard (France)

Soil and climate are major constituents of the French notion of Terroir. This concept implies that there is a strong relationship between the composition of the grape, the characteristics of the wine and the territory of production. To study this link, a new method of characterization of the Terroir, including geological and pedological factors, was investigated. It uses a field model based on depth and clay content of soil, together with the degree of weathering of the parent rock. Consequently, for every type of parent rock belonging to a given geologic stage, there are a series of soils that show different stages of pedological evolution. According to the model, three kinds of soils are distinguished with regards to the weathering intensity of the parent rock, that are named weakly weathered rock (WWR), moderately weathered rock (MWR) and strongly weathered rock (SWR). By hypothesis, each soil type is considered as a homogeneous unit for vine production from the viewpoint of ecophysiological factors. Each terroir unit defined by this method is called a Basic Terroir Unit (BTU). To validate this hypothesis, experimental plots planted with Chenin and Cabernet Franc vines were studied over three consecutive seasons (2000–2002), in the Anjou vineyard (Loire Valley – France). The major BTUs developed on the two most important geological systems of Anjou (Brioverian and Ordovician–Devonian), were studied. Results showed that the berries of vines cultivated in WWR were significantly smaller, richer in sugars and anthocyanins and had a Total Phenolic Index higher than those of the vines cultivated in SWR. They also had a lower titratable acidity. Cabernet Franc vines cultivated in MWR had berries with sugar and anthocyanin contents but also total phenolics very close to those of WWR. With Chenin vines there was a good relationship between the global pool of free aromas of berries and the BTU type. The study showed significant relationships between the quality of grapes and the measured values of several ecophysiological variables such as the water supply regime or the timing of budburst.

THE EVOLUTION OF THE QUALITY OF GRAPES AND WINES IN THE MURFATLAR CONDITIONS, YEARS 2004-2005

The Murfatlar vineyard biotope, by climatic, pedologic and relief factors had a strong influence on the physiological and biochemical vine process in all period of viticulture year. The climatic factors are those that have many variations who influenced in direct way harvest quality and quantity in each year. The research was made at Murfatlar in the 2004-2005 years. In this period were effectuated observations and determinations in entire vegetative period at the own clones and varieties: Pinot gris 13 Mf, Chardonnay 25 Mf, Columna and Mamaia. The climatic conditions of the mentioned period has a different evolution in comparison with multiyear mean, affecting the growing and maturation processes and the evolutions of the main diseases and pests. Analyzing the temperature factor it is observed an increasing of the yearly summation in all three years in comparison with the multiyear value – over 12,3 0C face with 11,0 0C. The pluviometric regimes show that these years had higher sums of the precipitation – over 550 mm given the normal with 419,8 mm but with precipitations repartitions, generally, outside of the vegetative period. Exception were registered in the August 2004 with 144,0 mm and July and September 2005 with 207,2 mm respectively 142,8 mm precipitations who generated an increasing of the main diseases attack.The downy mildew was manifested late in plantations, after 13.07. The powdery mildew was presented in each plantation with various intensities in concordance with number of treatments and type of fungicides applied. The gray dote was observed mainly on the Pinot gris grapes. The grapes mouth developed all three generations with attack frequency between 12 – 15 %.

Discriminant pedological factors of in situ specific moisture and available water content of African soils

The management of groundwater and crop-available water requires the knowledge of the hydrological behaviour of soils. A study was carried out from North to South Senegal on about 5 degrees of latitude, which cover a large range of pedological factors and various climatic, geologic and geomorphologic conditions. 1387 layer samples of 103 soils were taken from the surface to 2 m depth by 0.1 m-deep increments. The studied pedological properties were clay + silt content, bulk density, exchangeable Na + and pH. The hydraulic properties were the minimum moisture content, the field capacity and the available water content. Principal component analysis shows that the main factors, the texture, the minimum moisture content and field capacity, the available water content and the pH were in a decreasing order of importance. A good agreement between predicted and measured values of the minimum moisture content and the field capacity data, except for the available water content, was found for all mixed layers, for soils grouped according to their layers and for two soils (Arenosol and Ferralsol). However, the available water content can be calculated by statistical calculation by the grouping of textural classes for each layer.

Influence of soil protection techniques on runoff, erosion and plant production on semi-arid hillsides of Cabo Verde

A combination of human, climatic, geomorphological and pedological factors has led to extensive degradation of the soils of the Cabo Verde Islands. To survive in fragile conditions, the stabilisation of the farming systems and the maintenance of high and sustainable yields have become absolute priorities for farmers. The project described here is part of a programme of water resource optimisation on the island of Santiago in a semi-arid mountainous area near Godim. The objective of this study was to evaluate the influence of two conservation techniques (light mulching with maize ( Zea mays L.) haulms and hedging with bushes and grass) on runoff, erosion and phytomass production under natural rainfall. The main data were collected on five runoff plots of 100 m 2 and 10 pairs of 4 m 2 plots scattered over the hillslope. Although, rainfall erosivity was higher than in Sahelian areas, runoff occurred only for rainfall higher than 40 mm and intensities over 40 mm/h. Soil losses reached 12 mm/year on bare plots, 48 mm with traditional crops, 3.1 mm with hedges and less than 0.03 mm under mulching on 50% slopes. This study confirmed that mulching alone, or associated with the plantation of hedges, reduces runoff and erosion on the steep slopes of the Cabo Verde mountains. However, the ability to improve the use of the water resources by grain-producing crops in semi-arid regions was questionable. Plant material for mulching was only available and efficient during the wet years. The efficiency was therefore irregular and depended on the abundance of rainfall, weed production and the degree of satisfaction of plant water and nutrient requirements at the critical moment when the crops are in flower. Hedges of Leucaena leucocephala (Lam.) De Wit or Cajanus cajan (L.) Huth (Congo pea), without ditches or banks, planted on the flat and mulched could contribute to the supply of fodder in the dry season as well as blocking rivulet runoff and erosion in the Sahelian area.

Quality of virgin olive oil as influenced by origin area.

To elucidate the weight and the influence of the origin area on the analytical and compositional variables of olive oil, an investigation was carried out. Five Italian geographical zones were chosen. They were in the neighbour of the: (i) Faculty of Agriculture of University of Perugia (UNI-PG); (ii) the Olive Growing Institute-National Research Council of Perugia (NRC-PG); (iii) the Experimental Olive Growing Institute of Spoleto (EOI-SPOL); (iv) the Agricultural Technical Institute of Pescia (ATI-PES); and (v) the Faculty of Agriculture of University of Florence (UNI-FL). From these areas, Frantoio, Leccino and Moraiolo olive variety samples were taken, which were processed by a mini oil-mill. The research results showed that the quality, typicality and shelf-life parameters and the flavour of the oils were largely influenced by the origin zone, i.e., by the climatic and pedologic factors of the production environment. The influence exerted on some oil constituent groups, as phenols, tocopherols, aromatic volatile compounds, and fatty acids, should be emphasized as these components are closely related to the quality and typicality of product. Some oil genuineness parameters were affected as well by the environmental variables.

Assessing groundwater vulnerability to agrichemical contamination in the Midwest US

Agrichemicals (herbicides and nitrate) are significant sources of diffuse pollution to groundwater. Indirect methods are needed to assess the potential for groundwater contamination by diffuse sources because groundwater monitoring is too costly to adequately define the geographic extent of contamination at a regional or national scale. This paper presents examples of the application of statistical, overlay and index, and process-based modeling methods for groundwater vulnerability assessments to a variety of data from the Midwest U.S. The principles for vulnerability assessment include both intrinsic (pedologic, climatologic, and hydrogeologic factors) and specific (contaminant and other anthropogenic factors) vulnerability of a location. Statistical methods use the frequency of contaminant occurrence, contaminant concentration, or contamination probability as a response variable. Statistical assessments are useful for defining the relations among explanatory and response variables whether they define intrinsic or specific vulnerability. Multivariate statistical analyses are useful for ranking variables critical to estimating water quality responses of interest. Overlay and index methods involve intersecting maps of intrinsic and specific vulnerability properties and indexing the variables by applying appropriate weights. Deterministic models use process-based equations to simulate contaminant transport and are distinguished from the other methods in their potential to predict contaminant transport in both space and time. An example of a one-dimensional leaching model linked to a geographic information system (GIS) to define a regional metamodel for contamination in the Midwest is included.

Influence of pedological and climatic factors on nitrogen mineralization in soils treated with pig slurry compost

The influence of various climatic and pedological factors, including temperature, moisture, clay content and nitrifying agents, on nitrogen mineralization in three types of soil fertilized with pig slurry compost was studied. The results suggested that the time of incubation is the most influential factor on changes in the different nitrogen fractions. In addition, the lower the clay content of the soil the lower the final organic N content after incubation; on the other hand, the lower the temperature, greater the extent of mineralization (0.49–2.98% of total N at 30°C and 2.23–4.70% at 15°C). None of the climatic and pedological variables studied was found to have a significant effect on nitrogen losses, which never exceeded 46% of the initial amount of nitrogen.

Effects of botanical composition, soil origin and composition on mineral concentrations in dry season pastures in western Kenya

Abstract The influence of botanical (pasture species), geographical (altitude) and pedological (bedrock type, soil pH and extractable mineral concentration) factors on mineral concentrations in dry season pasture was studied in samples of topsoil and herbage from 135 sites on 84 farms in the Mt Elgon region of western Kenya. Of the four major elements measured in herbage, only S was affected by geology, low values being found above Tertiary volcanic (TV) and metamorphic gneiss (MG) bedrocks. By contrast, only P was not affected by species, Setaria being low and Kikuyu grass usually high in macro minerals. Of the seven trace elements analysed in herbage, geology influenced only one: Cu; low values were again found above TV and MG but Cu availability to grazing ruminants would be relatively high because of the associated low S values. By contrast, only Se was unaffected by species, Kikuyu grass being high in all but Mn. Soil bedrock had a greater influence on soil composition but correlations between extractable soil and herbage mineral concentrations were poor for all elements, even within botanical species after correction for soil pH and soil contamination. Concentrations of Ca, P, Mg, S, Cu and Zu were often less than tabulated requirements for grazing livestock. However, risks of deficiency could not be predicted from the pedological factors measured.

The significance of fragipans to early- Holocene slope failure: application of physically based modelling

Interpreting slope failure in the early Holocene has traditionally focused on climatic change. Little research considers the role of soil-profile characteristics, in particular the effect of fragipan occurrence. Fragipan formation has been associated with periglacial processes in northwest Europe, but recent evidence suggests that fully developed fragipans did not exist until 2000-3000 years after the close of the Lateglacial. Fragipans have been widely reported as having reduced permeability and altered soil moisture retention curves. The implications of such hydrological properties for slope stability is considered in this paper, by comparing stability of a soil profile containing a fragipan with one that is freely draining using a physically based soil hydrology-slope stability model. The results suggest differences in angles of limiting stability of 15° between the two soil profiles, while differences resulting from likely climatic variation are only 3-4°. Modelling results of maximum stable slope angles for fragipans are consistent with those reported in the landscape, placing confidence in model outputs. This is used as a basis for suggesting that pedologic factors might be more significant than climatic factors when interpreting early Holocene slope instability. The potential utility of physically based modelling is explored more generally, and suggestions are made for future research to elucidate more fully the role of fragipans in slope stability.

Climate, soils and Cephalcia arvensis outbreaks on Picea abies in the Italian Alps

The recent outbreaks (1986–1992) of the spruce web-spinning sawfly Cephalcia arvensis Panzer (Hymenoptera, Pamphiliidae) extended over 1500 ha of spruce ( Picea abies Karst.) stands in two areas of the Venetian Pre-Alps (north-east Italy). Among the possible causes of these outbreaks, the climatic and pedological factors seem to predominate: (1) the period 1983–1986 showed a hot and dry climate in both areas, especially during the developmental time of the pest (June–July); (2) sever water stress occurred in the same years preceding the outbreaks; (3) inside each area the insect attack was irregularly distributed, reflecting the variability in soil and stand features. The relationships between climate and attack levels could be interpreted in two complementary ways: (1) lower mortality and faster development of the insect induced by favourable climatic conditions (high temperatures and lack of precipitations); (2) increase of food quality as a consequence of the water stress suffered by the trees, according to the soil and stand characteristics.

A quantitative Australian approach to medium and small scale surveys based on soil stratigraphy and environmental correlation

Current methods of soil survey and land evaluation are based on transfer by analogy and results can be limited by the quality of the classification system used for mapping. Parametric soil survey is an alternative where predictions of individual soil characteristics and qualities, rather than soil types, are provided for the complete survey area. Predictions can be derived from either local soil classifications or interpolation and surface fitting procedures. The feasibility for a third approach to parametric survey has been investigated using data from the lower Macquarie Valley, NSW, Australia. Soil characteristics were predicted using generalized linear models with more readily observed environmental variables as predictors. These variables (e.g. geomorphic unit, local relief, etc.) are related to pedologic factors controlling soil distribution. A large percentage of variation for most soil characteristics was accounted for by pedoderms which were mapped using stratigraphic relationships determined in the field and by air photo interpretation. (Variation accounted for in the A horizon: clay content = 63.9%, CEC = 66.5%, EC = 26.5%, pH = 43.0%, bulk density = 33.3%, COLE = 61.2%, −10 kPa gravimetric water content = 66.4%, −1.5 MPa gravimetric water content = 64.0%; B horizon: clay content = 34.9%, CEC = 58.2%, ESP = 41.5%, EC = 17.2%, pH = 33.3%, bulk density = 32.1%, COLE = 59.9%, −10 kPa gravimetric water content = 55.5%, −1.5 MPa gravimetric water content = 39.8%). Within-pedoderm statistical models were developed with landform as an explanatory for several units and these further improved predictions. The potential of the approach in routine soil survey is discussed and the advantages of generalized linear models for analysing survey data are noted.

Distribution quantitative et qualitative des actinomycètes dans les horizons de sol de surface et profonds d'une palmeraie algérienne

Qualitative and quantitative distributions of actinomycetes were studied in surface and deeper soil horizons of a palm plantation in Algeria. The distributions were influenced directly by certain morphological and pedological factors of horizons, among which, the most important besides depth, were the quantity and quality of organic matter, clay abundance and calcareous content. Determination of 350 isolates showed that the genus Streptomyces was dominant in most of the horizons, with the exception of two of them, where Actinomadura and Nocardioides species were proliferating. However, whereas soil surface horizons contained very diversified species, each deeper horizon was characterized by the dominance of a particular species, often to a considerable extent. In a decreasing order of importance, the following species were found among the dominant: Streptomyces coerulescens in very deep reddish brown clay–silt sandy soils; Actinomadura cremea in light brown and sandy–silt soils; Nocardioides albus and Streptomyces aurantiogriseus in yellow nearly inorganic sandy soils. The influence of the above factors upon species distribution is discussed. Key words: actinomycetes, systematics, ecology. [Journal translation]

Geochemical soil surveys over cambrian and lower devonian formations in the belgian ardennes as a tool for geological mapping

A geochemical soil survey was made over outcropping Cambrian and Lower Devonian formations in the Belgian Ardennes. About 300 soil samples were collected in an area of 2.5 × 1.1 km2.Analysis of rock samples from scarce, but stratigraphically well-known outcrops show that the Cambrian rocks are richer in copper than those of the Lower and Upper Gedinnian (Lower Devonian). The Upper Gedinnian rocks are more nickeliferous than the other horizons.In the well-drained soils, copper and lead distributions permit precise location of the boundary between Cambrian and Lower Gedinnian formations. The nickel distribution seems to be a good stratigraphic indicator for distinguishing Upper from Lower Gedinnian. Zinc distribution seems unrelated to underlying bedrock geology.Regression analysis confirms that the content of Cu, Pb and Ni is essentially a function of lithostratigraphy. However, the distribution of these elements is more influenced by pedological factors in the poorly drained soils.

EVALUATING THE PRODUCTIVITY OF PINE FORESTS IN THE HINTON–EDSON AREA, ALBERTA, FROM SOIL SURVEY MAPS

Effective land use and land management policies are based ideally on data collected from land classification and land evaluation procedures. This paper describes a method employed in classifying and evaluating land for the production of lodge-pole pine (Pinus contorta var. latifolia) in the Hinton–Edson area of Alberta. Initially, a soil survey was conducted in the area. Productivity of various collections of soils was then obtained by statistically comparing soil information derived from the soils map with forest growth information obtained from the continuous forest inventory program of North Western Pulp and Power Limited of Hinton. Results indicate that aspect has minimal effect on pine productivity except for sandy and gravelly soils. General differences in growth were related to soil parent material, climate, drainage, and physiography, and more specific differences were attributed to soil subgroup, soil series, soil reaction, and percent slope. It was realized that pine growth is a function of pedological, landform, and climatological factors, and all must be considered when evaluating productivity.

EFFECTS OF TOPOGRAPHICAL POSITIONS, SOIL TEST VALUES, AND FERTILIZER USE ON YIELDS OF WHEAT IN A COMPLEX OF BLACK CHERNOZEMIC AND GLEYSOLIC SOILS

In southeastern Saskatchewan, from 1965 to 1968, wheat was grown in 15 experiments testing N, P, and NP fertilizers on 8–12% topographical slopes on an association of Black Chernozemic and Gleysolic soils developed on moderately rolling calcareous glacial till. All tests were on summer fallow. Without fertilizer, the yield of wheat ranged from 1150 kg/ha on the crown of the knolls to 1930 kg/ha in the depressions. Phosphate fertilizer increased the yield of grain by 20–30% on the crowns, upper slopes, and midslopes (70% of the area) and by less than 10% on the lower slopes and in the depressions. Excluding the depressional areas (10% of the area), the average phosphorus content was 10 ppm in the surface soil. The average NO3-N content of the top 60 cm of soil was 34 ppm. The basic pedological and microclimatological factors of the soil catena affected the yields of wheat more than soil fertility (and fertilizers).

Distribution of iron and manganese in meadow forest - non-calcic brown and gray-brown podzolic soils of the himachal pradesh (India)

Different forms of iron (total, free, reducible, extractable and exchangeable) and manganese (total, free, active, and exchangeable) have been fractionated from seven profiles of: (a) meadow forest; (b) non-calcic brown and (c) gray-brown podzolic soils of the Himachal Pradesh (India). Total and free Fe and total, free and active Mn generally show a pattern of distribution related both to the clay content, and to each other. This suggests that they are functions of the same pedological factors in these soils. The differences in the contents of total Fe and total Mn between the soil groups are due to the different proportions of these elements in the parent-materials. The abrupt increase of free Fe, and in some profiles of free Mn in illuvial horizons, is possibly a result of excess of mobilizing agent available just above these horizons. Reducible Fe does not show any definite pattern of distribution. Exchangeable Fe forms 17.6% of the extractable Fe. Exchangeable Fe 2+ forms a major portion (90%) of the total exchangeable Fe, but extractable Fe 2+ forms only 49% of the total extractable Fe. Significant correlations are found between exchangeable Fe and pH ( r = − 0.8759), and between exchangeable and extractable Fe ( r = + 0.7822). Exchangeable and extractable Fe are comparatively low in these soils. The proportions of free and active Mn oxides are related to total Mn whereas exchangeable Mn is related to soil organic matter.

TRACE ELEMENTS IN SOME WELSH UPLAND SOILS

SummaryUpland Welsh soils of rhyolitic origin contained less total Co, Cr, Cu, Ti, and V, more total La and Rb, and less acetic‐acid‐extractable Co and Cr than soils derived from dolerite, pumice tuff, and mixed drifts. Except for the surface enrichment of Pb, pedological factors appear to have had little effect on the distribution of total or extractable trace elements within these immature soils.