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Two sequential extraction methods (the modified BCR—Community Bureau of Reference, now the Standards, Measurement and Testing Program, of the European Commission—and the original Tessier) were compared for the assessment of various forms of copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) in 29 cultivated acidic soils of northern Greece. In addition, the different forms of the micronutrients extracted by the two methods were compared to the plant-available micronutrients extracted by diethylenetriaminepentaacetic acid (DTPA) and their relation to certain soil physicochemical properties was examined. Because the soils were acidic, the second step of the original method of Tessier (related to micronutrients bound to carbonates) was omitted. Consequently, four micronutrient fractions were assessed by both methods, namely water-soluble + exchangeable, bound to Fe-Mn oxides, bound to organic matter, and residual. Each of the two methods extracted different amounts of the same micronutrients in similar fractions, which amounts were significantly and positively correlated. The order of Fe and Mn distribution in the various fractions was similar in the two methods, within the same element, whereas Zn was slightly different and Cu was detectable only in the residual fraction of both methods. Clay and Fe-Mn oxide–bound Fe, cation exchange capacity (CEC), and organic matter–bound Fe were significantly and positively correlated in the case of the original Tessier method. In the modified BCR method, organic matter–bound Fe and Zn were significantly and positively correlated with CEC. In both methods, significant and positive correlation coefficients were found for the following relations: clay and Mn in the water-soluble + exchangeable fraction, organic C and organic matter–bound Mn, CEC and Mn in the three first fractions. The DTPA-extractable micronutrients were significantly and positively correlated with the respective micronutrients in the fractions bound to Fe-Mn oxides and bound to organic matter of the original method of Tessier for Zn; the fraction bound to Fe-Mn oxides of the same method for Fe; and the three first fractions of both sequential extraction methods for Mn. [ABSTRACT FROM AUTHOR]

Tobacco (Nicotiana tabacum) is one of the most important agricultural products in Greece. The accumulation of heavy metals in tobacco leaves in accordance with a possible risk of transferring them to people by smoke is well known. To monitoring heavy-metal contents in soils, as well as in tobacco leaves, a 6-year survey was conducted in the Thessaly region (central Greece). The concentration of zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), iron (Fe), and manganese (Mn) was measured both in soils and in air-cured (Burley), flue-cured (Virginia), and sun-cured (Oriental-filling) tobacco leaves in lower and upper leaves (primings). Regression analysis was conducted between soil and tobacco heavy-metal content to examine the possibility of predicting tobacco heavy-metal levels based on the results of soil analysis [diethylenetriaminepentaacetic acid (DTPA)-extractable levels]. The results showed a high correlation between Oriental tobacco heavy-metal content and DTPA-extracted heavy-metal level in soils. Although regressions based on the pooled data from the three tobacco types adequately predicted tobacco heavy-metal levels, better fits were obtained when regression models were used for Oriental tobacco separately. Statistically significant negative correlations were recorded between heavy-metal concentrations in Oriental tobacco leaves and soil pH, in all primings. Therefore, low soil pH value leads to an increased availability of heavy metals in tobacco leaves. [ABSTRACT FROM AUTHOR]

Twenty-seven soil samples were collected from surface horizons, in order to include representative soil types. Three samples per site were taken and mixed from the examined area, in spring 2005. The study area occupies 820 ha of the now-drained (1910), partially levelled, and continuously farmed Lake Askuris in Greece. The area, which is close to the village of Kalipefki (Longitude: 22° 27' 22'' E; Latitude: 39° 57' 39'' N) and to Mount Olympus, is elevated (≈1000 m) with a Mediterranean climate of mild, rainy winters and hot, dry summers. In addition to clay content, the soils were chemically characterized using 22 soil chemical tests, including pH, total carbon and organic matter, total nitrogen, total sulphur, exchangeable cations, cation exchange capacity, organic and extractable phosphorus (P), and pseudo-total and diethylenetriaminepentaacetic acid (DTPA) extractable trace elements. All of the soil data were skewed, with population mean values higher than the median for clay percentage, cation exchange capacity, carbon/nitrogen ratio, exchangeable calcium (Ca) and magnesium (Mg), DTPA iron (Fe), and total zinc (Zn). A geographic information system and kriging was used to prepare spatially explicit maps (at least two or three level of fertility) for the exchangeable basic cations, the trace elements, phosphorus, organic matter, total nitrogen (N), and total sulfur (S). It is expected these contemporary baseline data will assist the local community and farmers as they consider future nutrient management plans along with other land use options that could include re-flooding the lake bed.” [ABSTRACT FROM AUTHOR]

The main purpose of this investigation was the monitoring of nitrogen (N) and cadmium (Cd) levels in soils and irrigation water samples in an intensively cultivated area in central Greece. From 2005 to 2007, soil as well as irrigation water samples were collected two periods a year (March and October) at the same sampling sites in the Almyros area. Nitrogen was measured in three forms (as nitrate, nitrite, and ammonium) using the anion chromatography method. Available and total Cd concentrations were measured using atomic absorption spectroscopy, after extraction with diethylenetriaminepentaacetic acid (DTPA) and aqua regia extraction solutions, respectively. The nitrate, nitrite, ammonium, and Cd concentrations were always less than the corresponding water standards. Cadmium concentration (total and DTPA extractable) in soil samples was high in the sites where phosphate fertilizers had been intensively used for the crops. Seasonal variation was found in all parameters measured between the autumn and spring of each year. No temporal variation was found, as there was no statistical difference in nitrate, nitrite, and ammonium or in Cd concentration among the years of the study. A spatial variation was observed in all the parameters and was illustrated by the respective thematic maps. Thematic maps of predictions of the measured variables, as well as for pH and electrical conductivity, were generated using geostatistics as a helpful tool in sustainable soil management of the study area. The spatial variability of available Cd was found to follow the variability of soil pH, as highly available Cd concentration was observed in highly acid soils. Significant correlations among nitrate, nitrite, ammonium, available and total Cd, and soil physicochemical parameters were obtained and discussed. [ABSTRACT FROM AUTHOR]