COMPARISON OF TWO SIEVING AND SEDIMENTATION METHODS FOR DETERMINATION OF PARTICLE SIZE DISTRIBUTION – POSSIBILITIES AND LIMITATIONS OF INTERPRETATION

SažetakGranulometrijski sastav tla (GST) jedan je od najvažnijih parametara fizičkih značajki tla. Određivanje GST najčešće se temelji na kombinaciji mokrog prosijavanja i pipetiranja, a razlike između pojedinih metoda temelje se na različitim tretmanima uzoraka u pripremi suspenzije za mokro prosijavanje i pipetiranje. Kako je do sada u mnogim laboratorijima korištena metoda pripreme suspenzije s Na-pirofosfatom (i još se uvijek koristi), opravdana je upitnost usporedivosti rezultata s rezultatima normirane metode (norma ISO 11277). S obzirom na specifičnosti dviju metoda, postavljena je hipoteza o postojanju razlika između istih, bilo na razini granulometrijskog sastava ili teksturne interpretacije. U svezi s navedenim, cilj rada je testirati razlike između dviju navedenih metoda.Istraživanje je provedeno na 67 uzoraka šumskog tla, od čega je 15 uzoraka iz njegovog površinskog dijela. Dobiveni rezultati istraživanja pokazali su da nema statistički značajne razlike između metoda za sve uzorke, kako iz mineralnog i iz površinskog dijela tla. Utvrđena je visoka korelacija između udjela svih istovrsnih frakcija određenih po različitim metodama.U interpretaciji teksturnih oznaka na temelju teksturnog trokuta utvrđena je značajna razlika između frakcije pijeska i frakcije praha, dok kod frakcija gline nije bilo statistički značajne razlike. Veći udjel frakcije pijeska utvrđen je interpretcijom na temelju teksturnih klasa po staroj metodi, dok je za prah obrnut slučaj.The purpose of this research was to comparison of two sieving and sedimentation methods for determination of particle size distribution (PSD). Until 2009, PSD was determined at the Faculty of Forestry in Zagreb by a sieve and pipette method after soil preparation using Na-pyrophosphate according to the Pedological manual (old method) (Škorić, 1965). Since the opening of the ecological-pedological laboratory at the Forestry Faculty in 2009, PSD determination has been performed according to the ISO 11277 (2009) Standard. The most important difference between the two methods is that according to the ISO 11227 Standard, pre-treatment is accomplished with hydrogen peroxide which oxidizes the organic matter, so that PSD is determined only in mineral soil particles, while according to the old method, the organic matter was not removed at PSD determination.The purpose of this research was to establish whether there was a difference in the results of PSD determination between the old method and the ISO 11277 Standard in the overall number of samples and particularly in the topsoil. Another goal was to test the difference in the textural interpretation of PSD results obtained by these two methods.For the needs of the analysis, 67 forest soil samples were taken from two areas in Croatia. The two methods were compared in order to determine whether there was a statistically significant difference in the total number of the samples. A comparison was also made to determine whether there was a statistically significant difference between the samples taken from the topsoil layer, since according to ISO 11277 the organic matter largely found in the surface soil part oxidizes.Statistical analysis and t-test revealed no statistically significant difference in any single fraction from the topsoil layer between the old method and ISO 11277. A high correlation was found in the topsoil layer for all the measured fractions (r = 0.98 for coarse sand, r = 0.96 fine sand, r = 0.94 coarse silt, r = 0.84 fine silt and r = 0.97 clay) as well as in the all established samples (r = 0.99 for coarse sand, r = 0.97 fine sand, r = 0.89 coarse silt, r = 0.88 fine silt and r = 0.97 clay).Based on the classification into three main fractions (sand, silt and clay) a higher percentage of sand and a lower percentage of silt was established by the old method compared with ISO 11277. This difference is directly reflected on textural interpretation. No statistically significant difference between the two methods was found for the clay fraction

Floristic composition as an indicator of destabilisation of lowland forest ecosystems in Posavina

Background and Purpose: The succession of forests in the Posavina region follows a pattern from forests of black alder and ash through stands of pedunculate oak to pedunculate oak-hornbeam forests. In the past hundred years, this lowland area has been affected by a number of factors, among which anthropogenic influences hold a primary position. This has resulted in a considerable deviation from normal, natural succession. The purpose of this paper is to analyse the present condition, the degree of destabilisation and the future developmental trends of pedunculate oak stands by drawing on previous pedological, hydrological and vegetational research. One of the best indicators of the above is the ecoindicator values of the floristic composition. Materials and Methods: Phytocoenological relevés were taken in 25 localities of both stable and destabilised forest ecosystems of pedunculate oak in Žutica Forest. The principles of the Zurich-Montpellier School were applied for this process. The numerical analysis was carried out by means of SYN-TAX 2000 software. JUICE 6.3 and CANOCO 4.5 were also used to process the relevés, construct the phytocoenological tables and correlate species compositions and vegetation typeswith ecological factors. The obtained results were compared with the results of earlier ecological research. Results: Phytocoenological research revealed significant changes in the floristic composition. Ecoindicator values of plant species indicate a substantial change in ecological parameters and increased destabilisation, which leads to larger quantities of light, thermophilicity and humidity in sites. In addition, the sites are richer in nitrogen and the soil reaction becomes more basophilic, while central European species replace intermediary ones. Conclusions: The investigated plots show a regression process contrary to the normal direction of vegetation development in lowland areas. A return has been observed from the final community to transitional communities, and in some localities even to initial and pioneer communities

Utjecaj razina vode Vranskog jezera i Jadranskog mora na kemizam vode Vranskog jezera

The set objective of this field research was the determination of anomalous states in the Vrana Lake waters that might be the consequence of environmental pressure. We postulated that water quality in Vrana Lake Nature Park would be mainly influenced by the agriculture and impact of the sea and climate. Methods employed include analysis of dynamics of temperature and precipitation, sea water and lake water levels and water monitoring in a time period from January 2000 to December 2009. Adriatic Sea and Vrana Lake water levels were monitored at water gauges placed at two sites. Water sampling was carried out at two measuring points as a part of the national water monitoring program. Comparison of water fluctuation levels in the lake and the sea with concentration dynamics of calcium, magnesium, chloride and sulfate ions, reveals that the relationship between lake water levels and sea water levels has a powerful and direct impact on the chemical activity of the lake water. The alkalinity and high electro conductivity of lake water is the consequence of mixing process with seawater. Penetration of sea water into the lake corresponds with the duration and intensity of the dry periods. Data on lake water hardness in location Prosika follows the same trend as data regarding ions and electro conductivity at the same location. Since our data indicates that with the change in the lake water and the sea water levels, the salinity of the lake changes, we conclude that sea water is the major source of salt in the lake.Kao cilj istraživanja na terenu postavljena je determinacija anomalnih stanja u vodi Parka prirode Vransko jezero koja bi mogla biti posljedica pritisaka na okoliš. Očekuje se da pritisci na kakvoću vode Vranskog jezera dolaze od poljoprivrede u slivnom području, ali i utjecajem mora i klime. Metode uključuju analizu dinamike temperatura i oborina i dinamika razine morske i jezerske vode za razdoblje promatranja od siječnja 2000. do prosinca 2009. Dinamika razina mora i jezerske vode praćena je na vodokazima postavljenim na dvije lokacije. Uzorkovanje vode provedeno je na dvije mjerne točke u sklopu državnog praćenja stanja voda. Usporedbom dinamike razine vode u jezeru i razine mora s dinamikom koncentracije iona kalcija, magnezija, klora, te sulfatnog iona, vidljivo je da odnos razine vode u jezeru i razine mora ima direktan i snažan utjecaj na kemizam jezerske vode. Lužnatost i njena visoka električna vodljivost posljedica su miješanja s morskom vodom. Činjenica da se promjenom odnosa razine jezerske vode i razine mora mijenja i koncentracija soli u jezeru pokazuje da je morska voda izvor soli u jezeru. Prodor morske vode u jezero korespondira s dugotrajnošću i izraženošću sušnih razdoblja. Podatci o tvrdoći jezerske vode na Prosiki prate isti trend kao i podatci o ionima i električnoj vodljivosti. Činjenica da se promjenom odnosa razine jezerske vode i razine mora mijenja i koncentracija soli u jezeru pokazuje da je morska voda izvor soli u jezeru

The effect of parent material on physical and mineral soil properties on Medvednica nature park

Matični supstrat, uz klimu, reljef, organizme i vrijeme, predstavlja jedan od pet glavnih pedogenetskih čimbenika. S pedogeneskog stajališta najvažnija su svojstva matičnog supstrata: mineralni i kemijski sastav, način i intenzitet trošenja te sadržaj biogenih elemenata. Cilj ovog rada je utvrditi utjecaj različitih matičnih supstrata na fizičke i mineralne značajke tla. Na području PP Medvednice na šest različitih litoloških cjelina otvoreno je 80 pedoloških profila: metamorfne stijene – dominantno škriljevci, metamorfne stijene – dominantno filiti, magmatske stijene, pješčenjaci, lapori i lako trošivi vapnenci. Uzorci tla uzeti su po horizontima, a analizirani su oni iz humusnoakumulatinog (A-horizont) i B-horizonta. Određeni su sljedeći parametri: debljina horizonata, dubina profila, udjel skeleta, garnulometrijski sastav tla, postojanost strukturnih mikroagregata i mineralni sastav tla (XRD) metodom rendgenske difrakcije. Rezultati istraživanja pokazuju da postoje statistički značajne razlike između različitih litoloških cjelina za sve promatrane varijable osim debljine horizonata. Najveće dubine tla su povrh laporovitih stijena, a najmanje na dolomitiziranim vapnencima, što je ponajprije  uvjetovano načinom trošenja matičnog supstrata. Na svim istraživanim litološkim cjelinama, tla na području PP Medvednice vrlo su postojanih mikroagregata. U odnosu na B-horizont u humusnoakumulativnom horizontu utvrđena je veća postojanost strukturnih mikroagregata. Tla povrh lakotrošivih vapnenaca imaju statistički veći udjel gline i manji udjel krupnog i sitnog pijeska od tla ostalih litoloških cjelina. Za sve litološke cjeline teksturna oznaka najčešće je u rasponu od praškaste do glinaste ilovače, dok je na litološkoj cjelini povrh vapnenaca udjel gline statistički značajno veći, pa je teksturna oznaka u rasponu od praškaste glinuše do glinuše. Litološke cjeline povrh magmatskih i metamorfnih stijena imaju statistički značajno manji udjel minerala kvarca i veći udjel minerala klorita i feldspata u odnosu na sedimentne stijene.The highly complex lithological structure as well as topographic characteristics of the Medvednica area are responsible for its profound vegetational, micro-climatic and pedophysiographic diversity. In view of the quality of the original soil-forming material, the first place is taken by rocks and their detritus which directly govern soil physical composition. The best indicators of soil physical composition are its depth, colour, skeletal nature, particle size distribution, soil density, density of soil solid phase, total porosity, water capacity, air capacity, structure and hydraulic properties. On Medvednica, these vary greatly and play the main role in defining soil quality. The success of ecosystem management depends on the knowledge of the above factors. The goal of this research is to determine how the lithological base, or parent material, primarily affects physical (horizon thickness, profile depth, skelet proportion, soil texture, soil structure) and mineral soil properties.A total of 80 pedological profiles were opened in the Medvednica Nature Park area and evenly distributed so as to comprise all the representative lithological units. Samples of physically altered soils were taken from genetic horizons, as well as a fragment of rock, i.e. parent material, for the purpose of determining the lithological rock affiliation. Soil samples has been analayzed in the humus-accumulative (A horizon) and first under mineral horizon (mostly B horizon). The differences between the topsoil humus-accumulative and B horizon were statistically analyzed per lithological units. The samples were prepared (ISO 11464 2006) and analyzed in the laboratories of the Faculty of Forestry of the University of Zagreb and at the Croatian Geological Institute in Zagreb. According to FAO (2006), the following was determined in situ: the proportion of skelet per genetic horizon, horizon thicknesses and total profile depth. Laboratory analyses of the samples taken from genetic horizons included the particle size distribution according to ISO 11277:2009, stability of structural microaggregates according to Pernar et al. (2013) and mineral soil composition (XRD) using the X-ray diffraction method on X-ray diffractrometer X’Pert PRO MPD.For the needs of statistical analysis, parent material was divided into six characteristic units, leaning in part on the classification of Halamić et al. (2001) used during geochemical research of stream sediments on Medvednica. The lithological unit LIT1 is represented by metamorphic rocks, predominantly greenschists, muscovite chlorite and quartz-muscovite schists. The lithological unit LIT2 is represented by metamorphic rocks, predominantly phyllites. The lithological unit LIT3 consists of igneous rocks, predominantly diabases and spilites. The lithological unit LIT4 are Mesozoic clastic rocks of Lower Cretaceous age, and comprise sandstones, siltites and shales. The lithological unit LIT5 consists of Mesozoic and Tertiary clastic rocks dominantly represented by marls. LIT6 is made up of Tertiary carbonate rocks represented by lithotamnic limestones together with clay limestones (Figure 1).Statistical analysis was performed with Statistica 7 software. Descriptive statistics was made for all the analyzed variables, including the number of samples, arithmetic means and standard deviation. Differences between the analyzed variables by lithological units were tested with a one-way analysis of variance (ANOVA), on condition that the assumption of homogeneity of variance was satisfied. For those variables in which the test of homogeneity of variance was not satisfied, the Kruskal-Wallis non-parametric test was used. Type I error (a) of 5 % was considered statistically significant.The following soil types were identified in the opened pedological profiles: dystric cambisol, eutric cambisol, calcaric cambisol, stagnosol, regosol and luvisol (the percentage ratio by representation is 62 % – 19 % – 10 % – 4 % – 3 % – 2 %).Based on the comparison of soils formed in six different lithological units, it can be concluded that physical and mineral soil properties depending on type of litological units. Silty to clay loam is the most represented textural class in Medvednica Nature Park. It was found on metamorphic rocks above greenschist and phyllite, igneous rocks, sandstones and marls, whereas on easily weathered limestones the textural class ranges from silty clay to clay. The analysis of particle size distribution (content of individual fractions) showed that the profiles developed on silicate lithological parent material have on average higher sand content compared to the profiles developed on carbonate rocks, which is conditioned by the manner of parent rock weathering. Higher clay content above easily weathered limestones eventually led to variability of the textural class in relation to other lithological units. In all the investigated lithological units in terms of structural microaggregate stability, the soils in Medvednica Nature Park manifest highly stable microaggregates. In relation to the B-horizon, the humus-accumulative horizon revealed higher stability of structural microaggregates, which can be attributed to higher content of organic matter in the topsoil horizon. The soils above igneous and metamorphic rocks have significantly lower content of the mineral quartz and higher content of the minerals chlorite and feldspar in relation to the soil above sedimentary rocks. There was no difference in muscovite/illite contents in lithological substrates. Soil was the deepest above marl rocks and the shallowest above dolomitised limestones, which is primarily conditioned by the manner of parent material weathering.Our research highlights all the complexity and heterogeneity of the geological-lithological structure of Medvednica. In combination with other pedogenetic factors, it manifests even higher soil heterogeneity, which eventually causes problems in the processing and interpretation of the results.This research provides reference data on physical and mineral properties of soils in Medvednica Nature Park in the most represented lithological units. However, these data should be taken with caution and should be compared with the results of other similar studies, since the same lithological parent material may give rise to the formation of soils of different taxonomic affiliation, depending on the changes in the constellation of other pedogenetic factors (climate, vegetation, relief)

Soil properties in beech-fir forests on Mt. Medvednica (NW Croatia)

Background and Purpose: Beech-fir forests in Croatia have very broad edaphic amplitude. On Mt. Medvednica they are predominantly developed on dystric cambisol, but also, to a smaller extent, on several other soil types. The purpose of this paper was to investigate soil properties in these forests and establish relations with pedogenetic factors, and especially with the bedrock and the relief. Materials and Methods: Research was based on the study of 14 soil profiles and soil samples from the horizons, and on the analysis of 39 composite samples from the surface 5 cm of soil. The following parameters were assessed from the samples: pH in water and 0.01MCaCl2, the carbonate content, and the content of biogenic elements Org C., TotalN, P,K, Ca and Mg, as well as the texture of profile samples. Results: Dominant soils in beech-fir forests on Medvednica are dystric cambisol and eutric cambisol. Most of the profiles are situated on moderately steep and steep slopes, so their A-horizon is colluvially influenced. All profiles were shallower than 100 cm, except for the stagnosol profile. The most variable parameter in the surface 5 cm was organic carbon, ranging from 40.9 to 367.2 g kg–1, whereas the pH value measured in water suspension oscillated between 3.69 and 7.21 and corresponded with the calcium content in the soil, with carbonate substrates in the central part of the range and with carbonate quantity in the soil. Conclusions: The distribution range of beech-fir forests on Mt. Medvednica is highly complex both from the pedogenetic and pedophysiographic aspect. It provides a good basis for the application of more complex models of spatial prediction of soil properties, but also for phytocoenological and ecological management profiling of beech-fir forests

Recommendations for Soil Management in Croatia

A trend of rapid forest and particularly agricultural land area reduction due to different types of degradation has been present worldwide in the last decades, and so also in Croatia, whereat soil losses caused by land reallocation are especially dramatic. Besides that, we are witnesses of different forms of soil degradation associated with climate changes - from acidification, dehumification, pollution, erosion to desertification. To protect soils from all types of impairment, this highly important natural resource should be managed in a sustainable way. Hence, the objectives of this work were to present the land potential of Croatia, identify existing processes of soil damages and expressed threats, and offer recommendations for systematic land management, including organizational, administrative and practical measures

Impact of Eroded Terrain Recovery on Soil Proporties on Flysch – Case Studies of Abrami and Butoniga in Istria

Na dva lokaliteta na flišu u Istri istraživali smo utjecaj biolo ških i tehničkih mjera zaštite tla te sanacije erodiranog terena na svojstva tla, odnosno na njegovu regeneraciju. Na poligonu za istraživanje erozije u Abra mima istraživanje smo proveli na obnovljenim istraživačkim parcelama, a kod naselja Grimalda na zemljištu s umjetno podignutom sastojinom crnog bora. Pokazalo se da su tehničke mjere sanacije imale ključnu ulogu u smanjenju produkcije erozijskog nanosa, osobito u ranoj fazi trajanja pokusa. Isto tako na strmim padinama vegetacijska progresija je vrlo spora, pa je i regenera cija tla vrlo spora, tako da je usprkos prirodnom naseljavanju crnog bora sklapanje sastojine vrlo sporo, a humusno-akumulativni horizont tla vrlo slabo razvijen i fragmentiran. Na blažim nagibima, koji nisu bili jako erodi rani, nesmetano širenje prirodne vegetacije (zaštita od požara) podjednakog je učinka na svojstva tla (ujedno na njegovu zaštitu, regeneraciju itd.) kao i biološka sanacija u vidu sadnje crnog bora. Odnos godišnje produkcije erozij skog nanosa i sadržaja organske tvari u tlu upućuje na bržu humizaciju i rege neraciju tla kod primjene učinkovitijih mjera suzbijanja erozije.The impact of biological and technical soil protection measu res, as well as the effect of eroded terrain recovery on soil properties, i.e. its regeneration, was investigated in two localities on flysch in Istria. Seven re search plots in the erosion research polygon in Abrami were restored for the purpose of measuring annual sediment production by erosion. The condition of soil was investigated in five plots and its regeneration was compared in terms of terrain recovery methods. Two plots were excluded: one because the terrain was completely eroded and turned into bare marl detritus, and another because it was established only recently, therefore, soil properties have not yet been changed by the treatment. Near the village of Grimalda we analyzed the condition of surface soil in the part of the terrain that was afforested in 1982. We made two separate ana lyses: one in an established black pine stand and the other on abandoned grassland displaying natural progression of forest vegetation. According to our research, the soil in all five plots in the Abrami polygon is equally carbonate, while the pH value shows alkaline reaction. These proper ties are the consequence of past erosion processes, which have led to predomi nantly bare, homogeneous, detritus of flysch. As a result, the remaining material has similar properties regardless of the applied recovery methods. Soil in the areas that are not severely eroded is eutric cambisol, while severely eroded slopes are characterized by shallow regosol. Several recovery methods were applied. In the plots restored for the purpose of monitoring sediment pro duction by erosion we analyzed the impact of a) high bench terraces with dry wall crowns, b) low and mildly sloping bench terraces, c) classical planting with black pine into holes, d) planting with black pine into bench terraces and undersowing with a grass mixture and Spanish broom, e) planting with black pine into bench terraces without undersowing, and f) areas with varying ini tial vegetation condition and varying slope degrees. It was found that technical recovery measures had a key role in the reduc tion of sediment production by erosion, especially in the early stage of the ex­periment. It was also found that very slow vegetation progression on steep slopes results in very slow soil regeneration. Thus, despite natural coloniza tion with black pine, canopy closure is very slow, while the humus-accumula tive soil horizon is poorly developed and fragmented. On milder slopes that are not severely eroded, the undisturbed expansion of natural vegetation (fire protection) produces equal effects on soil properties (and its protection, rege­neration, and similar) as does biological recovery with planting black pine. This was confirmed by research in the Grimalda locality. The only difference is slightly higher soil water permeability in the pine culture. The annual sediment production by erosion in the experimental polygon of Abrami partially coincides with the organic matter content. These processes are reversely proportional, which indicates that soil humization and regenera tion will be more rapid if erosion prevention is more efficient, or in other words, if better technical and biological recovery measures are applied