Behavior of iron‐inefficient plants when grown in combinations of calcareous and noncalcareous soils

Abstract

When Fe‐inefficient plants were grown in mixtures of calcareous Hacienda loam soil and noncalcareous Yolo loam soil compared with plants grown in unmixed soils, characteristics and composition of the plants including Fe deficiency were generally intermediate to those with either soil alone. Noncalcareous soil adjacent to calcareous soil allowed PI 54619–5–1 soybeans (Glycine max L.) to obtain sufficient Fe.     

The composition of humus in permafrost-affected soils of the Bol’shezemel’skaya and Kolyma tundra areas

Tundra soils (except for the soils of barren circles) in the moderately and extremely continental tundra areas are characterized by the pronounced surface accumulation of humic substances. The humate-fulvate nature of humus is typical of the upper horizons of surface eluvial-gley soils, gley soils, and raw-humus mountainous brown soils; the C ha/C fa ratio in them varies from 0.5 to 0.91. The fulvate-humate nature of humus (C ha/C fa = 1.27–1.50) is typical of cryozems and sandy podburs. The first and the third fractions of humic substances (hs 1 and hs 3) predominate in the composition of humus. The coefficients of correlation (R) between the major parameters of soil humus and the physicochemical characteristics of tundra soils have been calculated. These coefficients between the contents of C org, C ha, C fa, C ha1, and C ha3 and the total acidity are equal to 0.73, 0.76, 0.72, 0.85, and 0.67, respectively; for the exchangeable Mg²⁺, their values are equal to 0.66, 0.88, 0.85, 0.74, and 0.90, respectively; and for the exchangeable Ca²⁺, 0.55, 0.47, 0.39, 0.41, and 0.61, respectively (p < 0.05). The composition of exchangeable cations and the total acidity specify the conditions of fractionation of humic substances in the studied soils. The differentiation of the qualitative composition of humus in the profiles of tundra soils is well pronounced and is mainly controlled by the distribution of clay and fine silt particles.     

The effect of sewage‐sludge on the heavy metal content of soils and plant tissue

Abstract

Domestic sewage sludge applied to farm fields at a rate of 44.9 kg/ha in a mixture with lime and sawdust was found to increase the soil levels of cadmium, chromium, copper, lead, mercury, nickel and zinc. The average levels in sludge treated soil were: 0.11, 0.56, 3.59, 2.72, 0.068, 1.49 and 2.57 ppm, respectively. The increases were small and the overall loading factors were well below recommended maximums. The uptake of these heavy metals by grass and legume plants was variable with cadmium, copper and zinc levels being higher in those plants growing in the sludge treated soils but only copper was significantly higher. The heavy metal contents found were all within the levels normally found in grass and legume plants. The higher mean concentration in plants growing on the sludge treated soils were cadmium 0.495; chromium 1.22; copper 12.3; lead 1.54; mercury 0.022; nickel 4.08 and zinc 28.4 ppm.     

Spatial variation of soil test phosphorus and potassium,oxalate‐extractable iron and aluminum,phosphorus‐retention index,and organic carbon content in soils of Western Australia

Abstract

Spatial variation of bicarbonate soil test phosphorus (P) and bicarbonate soil test potassium (K) was studied by measuring soil test values for 40 individual soil samples collected from random locations within eight uniform 100 m by 100 m field sites in south‐western Australia. In addition, for five of the sites, spatial variation of the three P sorption indices (ammonium oxalate extractable iron, ammonium oxalate extractable aluminum, and the P retention index) and of organic carbon (C) was measured for 20 individual soils samples. Spatial variation was found to be large, with coefficient of variation (CV) exceeding 20% in most cases, and 50% in some cases. It is therefore essential to collect an adequate number of soil samples from uniform areas in paddocks in order to provide a representative composite sample to measure the soil properties.     

Morphology and properties of the soils of permafrost peatlands in the southeast of the Bol’shezemel’skaya tundra

The morphology and properties of the soils of permafrost peatlands in the southeast of the Bol’shezemel’skaya tundra are characterized. The soils developing in the areas of barren peat circles differ from oligotrophic permafrost-affected peat soils (Cryic Histosols) of vegetated peat mounds in a number of morphological and physicochemical parameters. The soils of barren circles are characterized by the wellstructured surface horizons, relatively low exchangeable acidity, and higher rates of decomposition and humification of organic matter. It is shown that the development of barren peat circles on tops of peat mounds is favored by the activation of erosional and cryogenic processes in the topsoil. The role of winter wind erosion in the destruction of the upper peat and litter horizons is demonstrated. A comparative analysis of the temperature regime of soils of vegetated peat mounds and barren peat circles is presented. The soil–geocryological complex of peat mounds is a system consisting of three major layers: seasonally thawing layer–upper permafrost–underlying permafrost. The upper permafrost horizons of peat mounds at the depth of 50–90 cm are morphologically similar to the underlying permafrost. However, these layers differ in their physicochemical properties, especially in the composition and properties of their organic matter.     

Diagnostics of hydromorphism in soils of autonomous positions on the Severo-Sos’vinsk Upland (Western Siberia)

The complex studies of hydromorphism features in taiga weakly differentiated soils using morphological (color), chemical (iron content in different extracts, indicators of reducing conditions (IRIS)), and geobotanic (using the Ramenskii scale) methods have led to ambiguous conclusions. In all the soils, surface gleying was manifested. According to the results obtained by different methods, the maximum reduction processes were related to either the sublitter or the next deeper horizon. The Schwertmann coefficient, the criterion of Bodegom, and the Ramenskii scale indicated an increase of hydromorphism in the soils studied in the following sequence: the lower part of the ridge slopes drained by the small gullies < the middle part of the slopes < the flat tops of the ridges < the depression between the ridges. The morphological diagnostics of gleying proved to be a less sensitive method, which can recognize only the most contrasting hydromorphic soils. The lower horizons in some taiga soils have a bluish gray color probably not related to the recent soil hydromorphism.     

Distribution pattern of root‐supplied 59iron in iron‐sufficient and iron‐deficient bean plants

In order to study the iron (Fe) distribution pattern in bean plants with different Fe nutritional status, french bean (Phaseolus vulgaris L.) seedlings were precultured in a complete nutrient solution with 8x10^‐5 M FeEDTA for five days. Thereafter, plants were further supplied with 8x10^‐5 M FeEDTA (Fe‐sufficient) or with only 2x10^‐6 M FeEDTA (Fe‐deficient) for another eight days. At this stage, the Fe‐deficient plants had much lower chlorophyll contents and lower dry weight of the leaves but higher reducing capacity of the roots compared with the Fe‐sufficient plants. For studies on short‐term distribution of Fe, the Fe‐sufficient plants were supplied 8x10^‐5 M ⁵⁹FeEDTA (specific activity 9.9 GBq/mol) and the Fe‐deficient plants 1x10⁶ M ⁵⁹FeEDTA (specific activity 98.8 GBq/mol). The plants were harvested after 4 and 24 hours. Despite a much lower supply of ⁵⁹FeEDTA/(factor 80), the Fe‐deficient plants took up significantly more ⁵⁹Fe but translocated less to the shoots (14.6% after 24 h) compared with the Fe‐sufficient plants (29.4% after 24 h). However, regardless of the Fe nutritional status of the plants, the majority of ⁵⁹Fe was translocated in the primary leaves. Our results demonstrate a similar distribution patterns of root‐derived ⁵⁹Fe in the shoots of Fe‐sufficient and Fe‐deficient plants, and thus, no preferential direct translocation of Fe to the shoot apex in the Fe‐deficient plants.     

Sand mineralogy and related properties of some soils in South‐Western Nigeria

Abstract

Five representative soil profiles were excavated along a toposequence selected in the Itagunmodi area of South‐Western Nigeria. The soils were subjected to physical, chemical, and mineralogical analyses. The results indicated soils with high fine sand and clay contents, but low silt content. The soils were found to vary from slightly acid to strongly acid (pHH₂O = 4.0 to 6.2). Organic C, available P, and Kjeldahl N contents decreased with increasing depth. Cation exchange capacity (CEC) ranged from 3.11 to 28.75 cmol(+)/kg soil. Base saturation was low (<51%). From a total elemental analysis, Si was found to be the dominant element, followed by Al, and then Fe. Extractable P, and exchangeable K, Mg, and Ca were quite low. The dominant minerals in the fine sand fraction were quartz, feldspar, zircon, hornblende, tourmaline, and opaque ores. The variation in the zircon/tourmaline (two resistant minerals) ratios with depth suggests a stratification of the parent material. The change in the quartz/feldspar ratios was an indication that the degree of weathering in the soil profile is not uniform.     

Phytoindication of the water status and nutrient supply of oil-polluted soils in the middle reaches of the Ob’ River

The method of phytoindication of the soil water status and nutrient supply was applied to natural and oil-contaminated soils in the middle reaches of the Ob’ River. These soil characteristics were indirectly assessed using the ecological scales developed by L. G. Ramenskii. On this basis, changes in the soil water status and nutrient supply under the impact of soil contamination with oil and oil products were estimated for the particular soil and landscape conditions     

Use of basic salts of iron and zinc as plant amend‐ments in soils

Abstract

In a greenhouse experiment, the effects of adding zinc (Zn) and iron (Fe) as either their basic salts or as commercial chelates were compared for the production of lettuce. The basic salts were found to be as effective as the chelates in providing Zn and Fe as well as being more environmentally safe.     

Improvement of the X-ray radiometric method of lanthanides’ diagnostics in soils

There are scarce data on the content of lanthanides in the soils of Russia, which is explained by the difficulties in their identification. The improvement of X-ray radiometric analysis permitted us to analyze a significant group of lanthanides in soils, i.e., La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy. Methods of diagnostics are developed for different groups of lanthanides. The new procedure permitted achieving high accuracy in the measurement; the limit of the lanthanide identification in soils is equal to 2?C5 mg/kg. The new procedure allows revealing the particularities of heavy lanthanides?? distribution depending on the lithogenic and anthropogenic factors. The procedure is applicable for revealing the technogenic anomalies of heavy lanthanides and determining their content in soils within positive and weakly negative anomalies.     

The influence of spruce on acidity and nutrient content in soils of Northern Taiga dwarf shrub–green moss spruce forests

Presently, among the works considering the influence of forest trees on soil properties, the idea that spruce (Picea abies) promotes the acidification of soils predominates. The aim of this work is to assess the effects of spruce trees of different ages and Kraft classes on the acidity and content of available nutrient compounds in the soils under boreal dwarf shrub–green moss spruce forests by the example of forest soils in the Kola Peninsula. The soils are typical iron-illuvial podzols (Albic Rustic Podzols (Arenic)). Three probable ways of developing soils under spruce forests with the moss–dwarf shrub ground cover are considered. The soils under windfall–soil complexes of flat mesodepressions present the initial status. The acidity of organic soil horizons from the initial stage of mesodepression overgrowth to the formation of adult trees changed nonlinearly: the soil acidity reached its maximum under the 30–40-year-old trees and decreased under the trees older than 100 years. The contents of nitrogen and available nutrients increased. The acidity of the mineral soil horizons under the trees at the ages of 110–135 and 190–220 years was comparable, but higher than that under the 30–40-year-old trees. The differences in the strength and trends of the trees’ effect on the soils are explained by the age of spruce trees and their belonging to different Kraft classes.     

Use of 1,10‐phenanthroline in estimating metabolically active iron in plants

Abstract

If calcifuges are forced to grow on a calcareous soil, they usually develop chlorosis. However, total leaf iron (Fe) does not often correlate well with Fe deficiency symptoms. The extraction of ‘active’ Fe by 1 M HCl or Fe chelators, e.g., 1,10‐phenanthroline, may reflect the relation between chlorosis and Fe‐concentration in the leaves better than total Fe does. Extraction of ‘active’ Fe from leaves of wild plants by 1,10‐phenanthroline, citric acid and HC1 was compared. The 1,10‐phenanthroline was chosen for further methodological studies. All samples were extracted at indoor light conditions and analyzed by AAS because dark incubation did not influence the oxidation state of Fe and non‐specific light absorbance seemed to be high in colorimetric analysis. Washing of leaf material with H₂O seemed to clean the leaf surfaces equally well as with 0.1 M HCl. Only fresh leaf material was extracted, as pretreatment (freezing or drying) changed the extractability of Fe. An extraction time of 16 h was adequate for the herbaceous plants tested but not for Carex pilulifera, where extracted Fe increased linearly with time. The age of the extractant solution may play a role because 1,10‐phenanthroline had lost part of its chelation capacity after 6 weeks. The ratio of leaf weight:extractant volume did not influence the amount of Fe extracted, provided the same amount of chelator was supplied. The 1,10‐phenanthroline did not interfere with the Fe determination by AAS, and HCl pH 3 as used for the preparation of the extractants had only a marginal influence on Fe extractability compared to 1,10‐phenanthroline at pH 3. To get comparable results the extraction method should be standardized as much as possible. Samples can be stored in the refrigerator for several hours before adding the extractant and the extracts can be stored for a few days or frozen and measured on the same day, with the same instrument setting.     

Behavior of iron‐supplying materials in incubated calcareous soils 1

Two Fe chlorosis‐inducing calcareous soils were incubated for up to 5 months, at room temperature and field capacity, with Fe‐EDDHA, Fe‐DTPA, FeSO₄, an amino acid chelate “Fe‐Metalosate”;, an oxide “Micronized‐Iron”;, and a precipitated Fe‐S compound “Iron‐Sul”;. Other treatments included DTPA chelate alone, elemental S and H₂SO₄ at comparable rates. Both water‐soluble, and DTPA‐extractable Fe fractions were measured periodically from each sample. All water‐soluble sources decreased with time. Soluble Fe was highest after Fe‐EDDHA addition but was not detectable after “Fe‐Metalosate”; and FeSO₄. Acidification to neutralize CaCO₃ significantly increased DTPA‐extractable Fe, which remained high with increasing incubation time. “Micronized‐Iron”; and S had only a slight effect on DTPA‐ extractable Fe. Though Fe‐EDDHA is the most efficient Fe material, pelleted acidified Fe sources, i.e., “Iron‐Sul”;, may be more economical for some crops in the long term.     

The effect of digging activity of little souslik on soils of the first terrace of Khaki Sor in the Botkul’sk-Khaki depression

The effect of digging activity of little souslik (Spermophilus pygmaeus Pall.) on the microtopography and soils was studied in the areas with shallow saline groundwater developing under continental conditions for 10.5–12.7 ka. The portion of microtopographic features related to the digging activity was quantified. It was found that the micromounds formed by sousliks appear on recently dried surfaces with shallow saline groundwater. However, their portion in this case is less than 3% because of the poor vegetation and shallow groundwater. Then, with the lowering of the base of erosion and aging of the territory, the zoogenic effect becomes more pronounced. On the first terrace of Khaki Sor (salt lake), the digging activity of sousliks creates the initial heterogeneity of soils and vegetation. The soil cover is composed of the virgin quasigleyed solonchakous solonetzes under the Atriplex-Artemisia santonica association (Gypsic Salic Solonetz (Albic, Ruptic, Oxiaquic, Siltic)) and of the zooturbated solonetzes under the Artemisia santonica-A. lerchiana association (Endosalic Hypogypsic Gypsisol (Sodic, Siltic, Novic)). A comparative analysis of morphology and some chemical properties of virgin and zooturbated soils is given. The soils of souslik-made mounds are strongly mixed, and the structure of their horizons is completely disturbed. They are characterized by an increased total content of salts mainly due to gypsum accumulation. At the same time, the content of toxic salts in the soil profile remains rather high because of their ascending migration from the strongly saline groundwater. On the first terrace, the process of zoogenic amelioration of solonetzes by sousliks is limited and does not affect deep soil layers.     

Application of the Weng’s ratio for the identification of Zn, Cu, and Pb contamination in soils and sediments

Purpose

This work explores the application of the use of Zn, Cu, and Pb relative contents as a new type of normalization method for geochemical properties of soils and sediments in an Atlantic Basin (Anllóns River, NW Spain). The method is based on the conservative behavior of these elements, which exhibit a certain concentration ratio that remains stable as long as there are no human disturbances.

Materials and methods

The average relative contents of Zn, Cu, and Pb were calculated by dividing the concentration of each metal in soils or sediments, in the <63-μm fraction, by the sum of Zn, Cu, and Pb, expressed as a percentage. The evaluation of the sum of the average relative concentrations of Zn, Cu, and Pb (Ri), together with three standard deviations for each element, namely, Ri ± 3Si, allows a hexagon to be constructed, represented in ternary diagrams of Zn:Cu:Pb. Following the method proposed by Weng et al. (Environ Geol 45:79–85, 2003), those samples falling outside the hexagon must be considered outliers.

Results and discussion

Results obtained confimed the conservative behavior between the relative contents of Zn, Cu, and Pb in surficial samples (soils, bed, and suspended sediments). Only sediment cores displayed nonconservative behavior, showing a marked Pb enrichment, with respect to the surficial samples. When Zn, Cu, and Pb relative contents were plotted in ternary diagrams, outliers were best classified when the hexagon was drawn with standard deviations of samples from the study area. The hexagon drawn with an international database of soils and sediments showed a poorer classification of outliers.

Conclusions

The results showed that total Zn, Cu, and Pb relative contents may be employed to investigate anthropogenic disturbances of these elements in soils and sediments of the Anllóns River Basin, thus corroborating that this type of normalization may be employed as a tool to assess outliers in a contaminated area.     

Chromium III‐iron interaction in iron sufficient and iron deficient bean plants. II. Ultrastructural aspects

The influence of a growth stimulating low Cr III concentration (1.0 μM) on chloroplast ultrastructure, the Fe, Cr, and Mn content of chloroplast extracts, o‐phenantroline extractable leaf Fe, and catalase activity was studied in both Fe‐sufficient and Fe‐deficient bush bean (Phaseolus vulgaris L.) plants. Chromium supply hardly affected the chloroplast ultrastructure of Fe‐sufficient plants but significantly improved chloroplast ultrastructure in Fe‐deficient leaves. Generally, Cr supply did not significantly influence chloroplast Fe‐content, but increased the Fe/Mn ratio in Fe‐deficient chloroplasts. In leaves from Fe‐deficient plants, o‐phenantroline extractable Fe was significantly increased, while catalase activity was not significantly influenced by Cr supply. The possible mechanisms of the beneficial effects of Cr III in Fe‐deficient plants are discussed.     

Heterogeneity of podzolic soils and pestropol’e

A present-day definition is given for the concept of pestropol’e. The relationship of different soil parameters and their variation with the diversity of perennial grass is looked at under the conditions of developed agrocenosis. It is shown, using methods of linear algebra and multivariate statistics, that the physical properties of soil have the deciding effect on the yield of plants at this stage of agrocenosis development.     

Transformation of soil and plant cover contaminated with oil and salt water in the middle Ob’ river basin

Changes in the soil and plant cover caused by contamination with oil and salt water in the middle Ob’ river region were estimated using geoinformatic and geostatistic approaches. The largest technogenically salinized areas include oligotrophic peat soils due to the extensive spill of highly saline waters on the flat bog surface and eutrophic soils located in lower topographic positions. The natural self-purification of salinized mineral forest soils proceeds within 1–2 years after the spill. The dominant species of secondary plant communities were detected. Correlations were revealed between the residual oil and chloride contents and the total projective plant cover.     

Evaluation of available boron content using eight methods of extraction in different soils from Córdoba and sucre in Colombia

The aim was to evaluate eight methods of boron (B) extraction in different soils from Córdoba and Sucre, Colombia. 37 samples were collected at a depth of 0–20 cm and carried to Soil and Water Laboratory of University of Córdoba for its chemical characterization. The available boron was extracted with the following methods: modified hot water, calcium chloride (CaCl₂) 0.05, hydrochloric acid (HCl) 0.05, barium chloride (BaCl₂) 0.006, manitol 0.05 + CaCl₂ 0.01, Ca(H₂PO₄)₂H₂O 0.008 in mol L^?1, mehlich-1 and ammonium acetate (NH₄OAc) (1.0 mol L^?1, pH = 7.0). The major quantity of boron was extracted with mehlich-1, HCl 0.05 mol L^?1 and hot water, extracting 0.36, 0.29 and 0.26 mg kg^?1, respectively. The extracting solution that correlated with the hot water method was HCl 0.05 mol L^?1 (r = 0.81); followed by Ca(H₂PO₄)₂H₂O 0.008 mol L^?1 (r = 0.62) and mehlich-1 (r = 0.54). According to characteristic and heterogeneity of soils, we recommend HCl method to extract available boron.