SPECTROSCOPIC CHARACTERIZATION OF HUMIC SUBSTANCES OF ANTHROPOGENIC SOILS DERIVED FROM TERRA ROSSA

The aim of the study was spectroscopic characterization of humic substances andevaluation of humus quality of anthropogenic soils derived from Terra Rossa. Thestudy was conducted on 15 soil samples collected from top-soil horizon of olivegroves in Middle Dalmatia (Croatia). Total organic carbon was determinedaccording to Walkley-Black method (1934) and humic substances isolationfollowing procedure given by Schnitzer (1982). Spectroscopic characterization ofisolated humic substances was carried out by measuring absorbance in VIS spectralrange 400-700 nm and optical indices (Q4/6, E4/6) were calculated. SOC content intop-soil samples varied from 1.45% to 4.21% with mean value of 2.98%. Theabsorption spectrum showed monotonous decrease of absorbance from 400 to 700nm for all samples. The optical indices E4/6 and Q4/6 varied from 3.58 to 5.05 andfrom 3.91 to 5.04, respectively and indicated differences of humus quality. Theoptical index below 4, which implies a high quality of humus, was determined insix samples. The low humus quality (optical index above 4) was determined inother nine samples. The SOC content has significant positive correlation withoptical indices Q4/6 and E4/6. Soils with higher organic carbon content have lowerhumus quality.

Impact of sewage sludge application on the humus state of sod-podzolic soil of subcarpathia under energetic willow plantation

Aim. To determine the impact of energetic willow fertilization with sewage sludge (SS) and manure on the change in the humus state of sod-podzolic soil of Subcarpathia under energetic willow plantation. Methods. Soil samples were collected on the experimental fi eld of Ivano-Frankivsk College of LNAU. The humus con- tent was determined according to DSTU 4289:2004; that of its labile forms – according to DSTU 4732:2007, the content of organic matter in SS and manure – according to GOST 27980-88. Results. The application of sewage sludge for energetic willow grown in sod-podzolic soil of Subcarpathia led to the increase in the total humus content by 0.5–1.1 % compared to the control (without fertilizers). The use of SS preconditioned the change in the humus quality, including the increase in humic acids in humus by 0.05–0.07 %, which promoted the increase in the share of stable humus up to 68–70 % and the stabilization of the humus state of sod-podzolic soil. Conclusions. The application of sewage sludge impacts the change in the indices of humus quality, in particular, its group composition. The level of humic acids content in humus increases with the increase in the dose of the introduced sewage sludge and manure, based thereon. It ensures the increase in the share of stable humus in soil, which, in its turn, conditions the stabilization of humus state of sod-podzolic soil. However, this dependence weakens with depth.

Mapping the topsoil pH and humus quality of forest soils in the North Bohemian Jizerské hory Mts. region with ordinary, universal, and regression kriging: cross-validation comparison

North Bohemia belongs to one of the most heavily industrialized and polluted regions in Europe. The enormous acid deposition which culminated in the 1970s has largely contributed to the accelerated acidification process in the soils and consequently to the wide forest decline in North Bohemian mountains. In this paper we map the active topsoil pH and humus quality with ordinary, universal, and regression kriging and compare the accuracy of resulting maps with cross-validation. For the regression kriging we use two types of spatially exhaustive auxiliary information, first the altitude derived from digital elevation model and second the land cover classes derived from satellite imagery. The leave-one-out (cross-validation) statistics, i.e. mean error, root mean squared error, and mean squared deviation ratio, are taken for comparison since they are widely accepted as measurements of the accuracy of digital soil maps. The results show that the regression kriging is superior over other kriging methods in this case. Out of 97 sampling sites the regression kriging with land cover classes is the best predictor at 32 sites for pH and at 30 sites for humus quality, the regression kriging with altitude at 31 and 25 sites, the universal kriging at 21 and 23 sites, and the ordinary kriging at 13 and 18 sites. The highest number of best predictions for regression kriging implies that the topsoil pH and humus quality are driven approximately equally by land cover and altitude and little less by pure geographic position. Furthermore, the universal kriging maps show a northeast to southwest spatial trend of topsoil pH and a northwest to southeast spatial trend for humus quality.

Methods for the Assessment of Humic Substances Quality in Forest Soils

This paper is focused on soil organic matter quality assessment in acid forest soils. Soil samples were collected in the Jizera Mountains region. Vegetation cover of sampling sites was formed by spruce or beech monocultures. Humus quality was assessed by the ratio of absorbances of pyrophosphate soil extract at the wavelengths of 400 and 600 nm (A400/A600). Humus fractionation was performed on selected soil samples. DRIFT spectra of individual fractions were measured. Higher pH and lower C and N contents were found in beech forest than in spruce forest. A400/A600 well correlates with C and N contents (r = 0.510*** and 0.615***, respectively). C and N content increases as to humus quality decreases. DRIFT spectra of fulvic acids turned out to be unsuitable for describing differences in humus quality. DRIFT spectra of humic acids and humin were hence more suitable. The difference between spruce and beech forest was found in 1514.cm–1 (C=C bounds of benzene rings) and 1550 cm–1 (N-H bounds in monosubstituted amides) bands intensities. Humic acids and humin coming from the O horizons of beech forest are relatively enriched by nitrogen functional groups. Values of humic acids aromaticity index did not differ between beech and spruce forests. DRIFT spectroscopy was shown as a possible method for detailed humus quality studying.

The content and composition of humus in pseudogleys of slopes and plains in South Macva and Pocerina

The scope of this paper was to examine the influence of two subtypes of pseudogley soil (of planes and of slopes) and three different land uses (forest, grassland and arable land) on the content and composition of humus in south Macva and Pocerina. The humus content was determined by dichromate method, and hu?mus components were measured using the method proposed by Kononova and Bel?cikova. The studied soils are mostly characterized by low humus content. Humus content is significantly higher in pseudogleys of plains compared to pseudogleys of slopes. Pseudogleys under grass and crops have significantly lower content of humus compared to the pseudogleys under forest. Important characteristic of hu?mus composition of surface horizon is dominant portion of fulvic over humic acids. Pseudogleys of plains have statistically significant higher amount of humic acids. The composition of humus is significantly different in pseudogley under forest compared to pseudogleys under grass and crops: it has more fulvic acids, less humin, and lower Ch:Cf ratio. Changes in pseudogley land use have produced better humus quality.

Elevated soil copper content in a Bohemian vineyard as a result of fungicide application

A set of fifty samples were taken from soil surface layers of an anonymous vineyard in the Bohemia region of the Czech Republic. Samples were analysed for basic soil parameters including pH and humus content and quality and for potentially toxic elements Cu, Pb, Zn, Cd and Mn. When compared to soil guideline values, mean Cu exceeded the limit by 280%. Although other elements did not exceed the guideline value, Zn and Cd surpassed background concentrations by 108 and 187%, respectively. Mn did not occur in concentrations that are considered excessive with respect to common natural soil levels. A statistically significant correlation was observed for Cu and C_ox, but no significant correlation could be made between Cu and humus quality, suggesting that in this case, Cu retention in surface soil is more dependent on quantity of humic substances rather than humus quality. The unnaturally high accumulation of Cu in the surface horizon is certainly of anthropogenic origin; most likely due to long term application of copper-based fungicides. High observed values of Cd are probably a result of the soils parent material and application of fertilizers which may have contained cadmium compounds. Distribution maps illustrated a common trend of potentially toxic element accumulation in the western section of the study area plot. However, many variables which were unmeasured in this study could account for the distribution and therefore more detailed study is required before conclusions can be made regarding this occurrence. An analysis of wine produced at the vineyard showed that although the end product beverage contained insignificant amounts of Cu in both red and white wines, the white wine contained 0.026 mg/l of Cd; a value which could contribute considerably to exceeding the dietary allowable intake of cadmium. The investigation should be extended to analyse a wider range of wines produced from the vineyard with a focus on soil-plant-fruit-wine transfer of cadmium and/or production processes.

Vulnerability of soil aggregates in relation to soil properties

Stability of soil structure represents an indicator of soil quality. The aim of this paper was to assess the effect of soil properties on structure vulnerability in an Orthic Luvisol. The aggregates were most vulnerable to fast wetting (mean K_v1 = 9.99, i.e. this effect can decrease the aggregate size 9.99 times). Lower destruction was caused by slow wetting and drying (K_v2 = 3.70) and mechanical forces (K_v3 = 1.67). Fine silt (particles of 0.002–0.01 mm) was the most important soil characteristic decreasing aggregate vulnerability (r = –0.334, –0.248, and –0.393 for K_v1, K_v2, and K_v3, respectively). Silt (0.01–0.05 mm) increased vulnerability to fast wetting (r = 0.318). Very fine sand (0.05–0.1 mm) increased vulnerability to mechanical impacts (r = 0.307). Organic carbon decreased vulnerability only slightly. Humus quality was rather related to porosity. Higher moisture of samples in time of collection increased aggregate vulnerability. Multiple regression, used for description of the effect of basic soil properties, provided the best model for K_v1 (R² = 27.45%), the poorest for K_v2 (R² = 7.23%).

Factors of spatial distribution of forest floor properties in the Jizerské Mountains

The aim of this contribution was to describe spatial distribution of soil characteristics of forest floor in the JizerskéMountainsregion and to assess the effect of stand factors by means of geostatistics, using structural correlation coefficients. Most soil properties showed a low spatial dependence with variogram range of 6000 m. Kriged maps of spatial distribution of soil properties were created. Most characteristics were influenced by altitude. A general decrease of pH and Ca and Mg content and an increase of potentially toxic Al forms (Al_KCl) due to high S and N loading were demonstrated. An effect of liming on the decrease of Al_KCl content, and higher pH and Mg content and lower Al_KCl under beech forest were shown. Lower acidity and a better humus quality were found at higher altitudes under grass coverin spite of high S and N content. The ratios S/Ca and S/(Ca + Mg) can serve as an indicator of soil acidification level.

Assessment of transport risk of cadmium and lead on the basis of immobilisation capability of soil

The objective of this paper is the ambition to elaborate a system of evaluating the potential transport risk of inorganic risk elements, cadmium and lead, and of creating maps of the soil potential for the immobilisation of these risk elements. The categorisation of the potential immobilisation of cadmium and lead was realised on the basis of two layers, the layer of metal concentration (Cd or Pb) and the layer of potential soil sorption. The level of metal concentration was evaluated according to the Slovak Soil Law. The potential soil sorption (PSS) of cadmium and lead is defined by qualitative parameters (soil reaction – pH value, optical parameter of humus quality – Q⁴₆) and quantitative factors (Corg, H – depth of humus horizon) and was evaluated according to the Eq.: [PSS] = F(pH) + F(Q⁴₆) + F(Corg) × F(H). On the basis of this rating, maps of categorisation of cadmium and lead potential immobilisation were created. These maps of the soil immobilisation potential show the distribution into five categories of Cd and Pb potential immobilisation.