Due to their characteristic properties, mountain soils require adequate management if used for cropping or grazing, even if climatic conditions are favorable. This study provides a summary of a three-year field campaign that evaluated mountain soils in in northern Georgia for sustainable agricultural use. Soils in the Kazbegi study area, located on the northern slope of the Great Caucasian Ridge, were mapped in 2014 and 2015. The soils developed mainly on sediment fans and on glacial and fluvial sediments. They were characterized by a low to moderate yield potential, with high-yield soils found on volcanic plateaus. Despite the high diversity of terrestrial and semi-terrestrial soils, common to all of them was a high humus content. In the river valleys, Fluvisols (or at least soils with fluvic-properties) were widespread and in the valley depressions fens, e.g., Histosols, occurred as well. On volcanic substrates, medium to very deep Cambisols or Umbrisols were found, with moderate to good agricultural yield potentials. However, P-sorption, mainly on amorphous Al- and Fe-oxides, could lead to an increased need for fertilization. Cambisols were present on moraine, and primarily Regosols and Cambisols on the clay and silt-rich sedimentary rocks of the Jurassic, including a widely distributed coarse fraction. The cambic horizon was not visually apparent but was clearly detectable analytically. Depending on the slope inclination and exposure, even Leptosols occurred on the slopes and peaks of sedimentary or volcanic rocks. Based on these results, a synthetic soil map merging geological and geodetic data as well as data from field mapping was created to provide an instrument for land use management.

Mountain regions cover one quarter of the Earth's terrestrial surface, and are both valuable and vulnerable areas with complex human-environmental interrelationships. In this coupled system, land-use changes induced by political or socio-economic transformations generate consequences for ecological landscape functions like soil productivity and species richness, and integrative land-use concepts provide the potential of a sustainable land development. In the Kazbegi region in the central Greater Caucasus of Georgia, these transformations further lead to landscape-structure change and population marginalization. Hence, we developed three agricultural land-use scenarios that meet Agenda 2030 Sustainable Development Goals to ensure a sustainable rural land development and the conservation of mountain ecosystems. Our normative scenario approach integrates quantitative and qualitative findings of empirical research in landscape ecology, soil science, vegetation ecology as well as agronomics and socio-economics. According to the examined environmental and socio-economic resources, we defined various scenario logics and normative assumptions that combine optimized livestock production (in dairy cow keeping and cattle fattening) with ecological limitations to maintain the functioning of mountain ecosystems. The rule-based scenarios achieved measurably increased outputs in biomass yields, livestock production and related revenues at the regional scale. Further, GIS generated scenario maps demonstrate the related land-use patterns spatially explicit and in high resolution, and visualize the alternative future from local to the regional scale. In conclusion, scenario development helps to determine region-specific and integrated land-use options to provide a sound base for land users and decision makers. Based on research on multiple landscape functions, this approach can assist sustainable land development in a mountain region.

Soils of the alpine ecosystem of Kazbegi region were investigated according to the Muencheberg Soil Quality Rating (M-SQR). Most limiting factors are climate as well as steepness, while the low nutrient supply and soil acidity can be tackled by adequate fertilization and liming practice. Inorganic or organic pollution were not detected. Soils on sediment fans as well as glacial sediments, mostly Cambisols (Humic), are characterized by a low to moderate yield potential while high-yield soils, mostly Cambic Umbrisols, can be found on volcanic plateaus. A common element of all soils is the high humus content. Actually, most of them are used only for pasture, due to poor accessibility. Soils on fluvial deposits, mostly Fluvisols, show a very high range of M-SQR-scores. Altogether, the soils of the study area have the actually untapped potential to optimize the basic supply of the local population as well as tourism also by cultivation of cereals. Nevertheless, variety trials on different soil forming substrates as well as erosion control are major preconditions for successful implementation of new cropping systems in the Kazbegi region. Furthermore, particularly rare soils, e.g. Cambisols on Tephra, should be protected.

Agriculturally used soils (Kastanozems) of experimental fields in the Mashavera Valley in southeast Georgia show various degrees of trace metal contamination (Cd, Cu, and Zn). Therefore, one part of the soils was remediated with iron grit. The effects of the remediation in comparison to nonremediated soils on microbial diversity and activity were analyzed with the single-strand conformation polymorphism (SSCP) and microbial respiratory activity. All topsoils were characterized by neutral to weakly alkaline pH values, high contents of Corg, and clay. The total contents ranged between 0.46 and 5.89 mg kg−1 for Cd, between 1.19 and 81.4 mg kg−1 for Cu, and between 210 and 976 mg kg−1 for Zn. Basal respiration was significantly (p ≤ 0.05) lower in the heavily contaminated soils as compared to the weakly contaminated and control soils. Phylogenetic analyses of the DNA bands found 40 operational taxonomic units with ≥98 % sequence identity. The phylum Acidobacteria dominated with 57.7 %. Other groups detected were Proteobacteria (α (2.8 %), β (8.5 %), γ (14.1 %), δ (4.2 %)), Bacteroidetes (5.6 %), Firmicutes (4.2 %), Actinobacteria (1.4 %), and Nitrospira (1.4 %). Furthermore, the results of the SSCP analysis and the Shannon–Weaver indices suggested that microbial diversity was lower in the heavily contaminated soils, but DNA band profiles of the remediated soils were in higher number than in the untreated soils. Due to the remediation, a recovery of the microbial diversity seems attainable.

The aim was to find an adequate, cost-efficient in situ remediation technique for the Mashavera valley, a mining area in SE Georgia heavily contaminated with Cd, Cu, and Zn. A 12-month experiment was conducted to test: iron grit, natural zeolite, biochar, and Divergan (R) (a scavenger) for soil melioration. The amendments were added in different concentrations to the topsoil of a Kastanozem. Mobile metal concentrations decreased with increasing concentrations of amendments in the sequence Divergan (R) >> iron grit approximate to natural zeolite > biochar. In the same order amendments enhanced activities of soil microbial respiration, alkaline phosphatase, and dehydrogenase; microbial C also followed this trend. A sequential extraction confirmed a shift from easily mobilized to heavily bound fractions. The addition of 2% (w/w) of Divergan (R) was sufficient to lower mobile trace metal concentrations below German thresholds by chemisorption, and soil microbial activity was significantly increased. The effects of all other treatments were at a much lower level and not found suitable due to needed application rates.

Bie Boden des Mashavera-Tals (SE-Georgien) werden seit Jahrzehnten mit durch Buntmetallbergbau belastetet Wassser des Flusses Mashavera bewassert. Die daraus resultierenden hohen Cd, Cu und Zn Gehalte der Oberboden stellen ein erhebliches Belastungspotenzial fur die Nahrungskette dar. Im Gefasversuch gelang es durch Zugabe von Divergan® (ein Polyvinylpyrrolidon)die Spurenmetalle in schwer mobilisierbare Fraktionen zu uberfuhren und dadurch die Pflanzenaufnahme zu reduzieren. Ob das Verfahren auch als Sanierungsstrategie im Mashavera-Tal anwendbar ist, muss aber zunachst noch im Feldversuch getestet werden.

The topsoils of the Mashavera valley in SE Georgia are highly contaminated with Cu, Zn and Cd from mining activities in the upper reaches of the Mashavera River. Previous laboratory experiments have shown that an in situ immobilization of these metals (M) by Fe-oxides would be an adequate remediation technique for the study area. A field experiment was thus initiated in 2008 in order to assess such a treatment under natural conditions. To verify the results a pot experiment was conducted in a growth chamber. Two experimental fields with differing degrees of M contamination were chosen close to the town of Bolnisi, Georgia, and divided into 8 (Field I, weakly contaminated) and 16 (Field II, heavily contaminated) plots. Half of the plots at each field were chosen for remediation. A 1% (w/w) zerovalent iron grit was applied homogeneously and mixed in the topsoils (to a depth of 0–20 cm) of the treatment plots. Composite samples of all plots were taken directly after remediation in March, June and October 2008 and again in March and October 2009. Spinacia oleracea L. was cultivated from March to June 2008 and 2009. Mobile fractions of Cu, Zn and Cd in topsoil, M concentration of Spinacia oleracea L., contents of amorphous Fe-oxides, changes of soil pH and plant available inorganic P were then determined in 2008 and 2009. In the pot experiment topsoil of Field II was mixed with 1% (w/w) zerovalent iron grit, incubated for 4 weeks and subsequently Spinacia oleracea L. was cultivated for 4 weeks. Mobile fractions of Cu, Zn and Cd in soil, M concentration of Spinacia oleracea L., changes of soil pH and plant available inorganic P were also determined. The mobile fraction of Cu decreased significantly to 48% from March 2008 to October 2009 in the treated soils of Field I. In the control soils, mobile Cu also decreased significantly to 52%. In soils treated with iron grit in Field II, mobile Cu and Cd decreased significantly to 20% and 51%, respectively, while in the control soils no significant changes were found. These results were confirmed by data from the pot experiment. The significant decrease of mobile Cu and Cd concentrations is due to the formation of amorphous Fe-oxides after application of iron grit and fixation of M by innerspheric complexes. Nevertheless, plant uptake of M was not affected by the Fe treatment in the field experiment. In the pot experiment, plant growth increased in Fe treatment. In addition, Cd uptake of Spinacia oleracea L. increased while Cu uptake decreased in the treatment of the pot experiment. No influence of remediation on soil pH was detected. In the treatments, soil-P availability was reduced in the field as well as in the pot experiment. This could be traced back to P-fixation by freshly-formed amorphous Fe-oxides. Nevertheless, levels were still sufficiently high according to German regulations. The application of iron grit as an in situ remediation is suitable only to a limited extent for topsoils of the study area. The efficiency to reduce mobile M by application of 1% (w/w) zerovalent iron grit decreased in the sequence Cu > Cd > Zn. The decrease was higher if the mobile fraction had a higher portion of the total content. Soil pH was not affected and plant available inorganic P was only marginally affected by the remediation but plant uptake of Cd, the most important criteria, was not reduced.

Am Standort einer ehemaligen Fabrikation des Farbpigmentes „Schweinfurter Grün“ weist eine eng begrenzte Kontaminationszone im Grundwasser auf die Wirksamkeit natürlicher Rückhalteprozesse hin. Sequenzielle Extraktionen in Verbindung mit der Ermittlung weiterer Bodenmerkmale wie Karbonatgehalt, Glühverlust und Kationenaustauschkapazität machen unter Berücksichtigung des Extraktionsverhaltens des Farbpigmentes v.a. Eisenoxide und -hydroxide als wichtige Adsorber für Kupfer und auch für Arsen wahrscheinlich. Das Rückhaltepotenzial für Kupfer kann v.a. aufgrund der pH-gesteuerten geringen Löslichkeit als gut bewertet werden. Für Arsen lässt sich neben der spezifischen Adsorption an Eisenoxiden auch ein hoher unspezifisch gebundener, leicht mobilisierbarer Anteil feststellen. Grundwasseruntersuchungen zeigen, dass die Eintragsform des Arsen als dreiwertige Spezies in suboxischen Bereichen des Aquifers metastabil erhalten bleibt. In oxischen Zonen erfolgt eine Oxidation in die fünfwertige Form.

The sharply confined pattern of arsenic groundwater contamination at the site of a historic dye factory suggests that natural attenuation processes are active and efficient. The supporting data included sequential soil extractions combined with analyses of other soil properties like carbonate content, the loss of ignition and cation exchange capacity and the extraction characteristics of the original dye pigment. The results point to iron oxides and iron hydroxides as the most important adsorbers for copper and arsenic. The attenuation of copper can be estimated to be very efficient mainly due to its pH-controlled low solubility. Besides the specific adsorption to iron oxides, however, arsenic exhibits a rather large, loosely bound and easily exchangeable fraction. The speciation of arsenic in groundwater is dominated by As(V). The oxidation state of the original pigment is As(III). In some parts of the aquifer where sub-oxic conditions prevail, this oxidation state is conserved. In oxic zones of the aquifer, oxidation to the pentavalent form As(V) takes place.