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The creation of high quality plants and their maintenance depends, primarily, on proper fertilization, deriving mainly from the knowledge of their nutrient requirements (NR). Spray-applied chlormequat chloride (CCC), at the concentrations of 3000 and 6000 mg L-1, has been reported to contribute to the production of attractively flowering Lantana camara L. subsp. camara (lantana) plants. However, no information is available about the NR of these plants. The effects of the aforementioned CCC concentrations plus 0 mg L-1 (control) on specific leaf area (SLA) and leaf potassium (K), phosphorus (P), calcium (Ca), iron (Fe) and manganese (Mn) contents of lantanas were examined under the 0% and 66% shading levels. Chlormequat chloride (3000 and 6000 mg L-1) decreased, generally, SLA of lantanas compared to control, at both shadings. Increased SLA values were estimated with increased shading. Phosphorus content increased with the increased CCC concentrations at 66% shading level. Phosphorus and Fe contents increased while Ca and Mn decreased with the increasing shading. The results of our study may contribute to the planning of a fertilization program for CCC-treated Lantana plants, a promising genus in landscaping in many countries around the world. [ABSTRACT FROM AUTHOR]

The internal structure, iron and manganese distributions of Fe-Mn nodules from imperfectly drained soils of central Greece were studied by scanning electron microscopy (SEM) and elemental analysis. Nodules exhibited a differentiated structure with discontinuous concentric rings as expression of their redox history. Fe and Mn have shown distinct repartition and were distributed mainly in concentric bands. The microstructure and the arrangement of iron-manganese compounds reflect the periodical development and the relative slow accretion rates of the studied nodules. These properties provide ample opportunity for adsorption and isolation of heavy metals from the soil system. [ABSTRACT FROM AUTHOR]

Organic farming has been proposed as an alternative agricultural system to help solve environmental problems, like the sustainable management of soil micronutrients, without inputs of chemical fertilizers. The purposes of this study were: i) to assess Fe, Mn, Zn and Cu bioavailability through the determination of sequentially extracted chemical forms (fractions) and their correlation with foliar micronutrient concentrations in mature organic olive (cv. ‘Chondrolia Chalkidikis’) groves; ii) to determine the soil depth and the available forms (fractions) by which the 4 metals are taken up by olive trees. DTPA extractable (from the soil layers 0–20, 20–40 and 40–60 cm) and foliar micronutrient concentrations were determined in two organic olive groves. Using the Tessier fractionation, five fractions, for all the metals, were found: exchangeable, bound to carbonates (acid–soluble), bound to Fe-Mn oxides (reducible), organic (oxidizable), as well as residual form. Our results indicated that Fe was taken up by the olive trees as organic complex, mainly from the soil layer 40–60 cm. Manganese was taken up from the exchangeable fraction (0–20 cm); Zinc was taken up as organic complex from the layers 0–20 and 40–60 cm, as well as in the exchangeable form from the upper 20 cm. Copper was taken up from the soil layers 0–20 and 40–60 cm as soluble organic complex, and as exchangeable ion from the upper 20 cm. Our data reveal the crucial role of organic matter to sustain metal (Fe, Zn and Cu) uptake -as soluble complexes-by olive trees, in mature organic groves grown on calcareous soils; it is also expected that these data will constitute a thorough insight and useful tool towards a successful nutrient and organic C management for organic olive groves, since no serious nutritional deficiencies were found. [ABSTRACT FROM AUTHOR]

Olive is the most important fruit tree species grown in Mediterranean basin, where many times it grows under saline conditions, due to irrigation with low quality water. Olive response to salinity is cultivar dependent and the evaluation of native genotypes is an important tool in finding tolerant genetic material. For this reason, five Greek olive cultivars, i.e. "Koroneiki", "Gaidourelia", "Lefkolia Serron", "N-K Gigas" and "Throumbolia", were evaluated regarding their tolerance to sodium chloride salinity (0, 50, 100 and 200 mM). All cultivars exhibited a significant reduction of growth, while the most severe symptoms were found in "Gaidourelia" while "Lefkolia Serron" presented the least symptoms. The latter exhibited the lowest sodium concentration in the leaves and the highest in the roots. Both potassium to sodium and calcium to sodium ratios were high in "Gaidourelia" leaves and stems, suggesting that the use of nutrient concentration for comparison of olive tolerance among cultivars could lead to erroneous results. The best indicator proved to be the determination of nutrient relative concentration compared to corresponding cultivar's control, as "Gaidourelia" exhibited the highest sodium relative concentration as well as the lowest nutrient ratios, revealing its inability to restrain sodium in the root level. [ABSTRACT FROM AUTHOR]

In the present study we investigated the sorption behavior of Cs in four different soils (sandyloam, loam, clayloam and clay) by using batch experiment. Cs sorption characteristics of the studied soils were examined at 4mgL−1 Cs concentration, at various pH levels, at room temperature and with 0.01M CaCl2 as a background electrolyte. Among different soils the decrease of k d (distribution coefficient) of cesium, at all pH levels, followed the sequence sandyloam>loam>clayloam>clay, indicating that the particle size fractions and especially the clay content plays predominant role on sorption of Cs. The effect of pH on cesium sorption displays a similar pattern for all soils, depending on soil type. At acid pH levels less cesium was sorbed, due to a greater competition with other cations for available sorption sites. The maximum sorption of Cs was observed at pH 8, where the negative charge density on the surface of the absorbents was the highest. For all soils was observed significantly lower Cs sorption at pH 10. [Copyright &y& Elsevier]