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The effect of decarbonation on group and fractional composition of humus in rendzina soils was investigated in 24 profiles of calcaric and 9 profiles of non-calcaric rendzina soils in different parts of Serbia that are characteristic of that soil type. One or two samples, depending on soil depth, were collected from horizon A and one from each transitional AC horizon in profiles where the AC horizon has developed. The more alkaline the soil pH is in highly and very highly calcareous profiles, the greater is increase in mobile fractions and decrease in stable fractions of humic and fulvic acids. Decarbonation was found to have a sig­nificant statistical effect on the fractional composition of fulvic acids (the content of their mobile fractions la and 1 increased, while fraction 3 de­creased), and the content of mobile humus (sum 1) increased, while stable humus content decreased (sum 2). However, stable humus was still found to account for over 80% even in non-calcaric rendzinas. The process of decar­bonation was not found to affect the group composition and type of humus, or the fractional composition of humic acids., Istraživanja uticaja procesa izluživanja na grupni i frakcioni sastav humusa u rendzinama obuhvatila su 24 profila karbonatne i 9 profila izlužene rendzine iz raznih delova Srbije karakterističnih za ovaj tip zemljišta. Iz A horizonta uzet je jedan ili dva uzorka, zavisno od dubine, i po jedan uzorak iz prelaznog AC horizonta, u profilima koji su imali razvijen AC horizont. Rezultati su pokazali da što je hemijska reakcija zemljišta alkalinija, u jako i veoma jako karbonatnim profilima rendzina Srbije, dolazi do povećanja udela mobilnih, a smanjenja udela stabilnih frakcija huminskih i fulvo kiselina. Proces izluživanja (ispiranje CaCO3, niži pH i stepen zasićenosti bazama) u zemljištima tipa rendzina u Srbiji statistički je značajno uticao na frakcioni sastav fulvo kiselina (povećao se sadržaj mobilnih frakcija fulvo kiselina - la i 1, a smanjio sadržaj frakcije 3 fulvo kiselina) i došlo je do povećanja sadržaja mobilnog dela humusa (zbira 1), a smanjio se udeo stabilnog dela humusa (zbira 2). Proces izluživanja doveo je do ispiranja baza, povećavanja kiselosti zemljišta odnosno smanjenja stepena njegove zasićenosti baznim katjonima. Novonastali uslovi uticali su na povećanje udela mobilnog humusa, odnosno na smanjenje stabilnosti humusa u izluženim rednzinama. Ipak, proces izluživanja spustio je reakciju zemljišta u izluženim rendzinama samo do srednje kisele, a zasićenost bazama je još uvek visoka, tako da i dalje preovlađuje stabilni deo humusa, u proseku sa preko 80%. Proces izluživanja nije značajno uticao na grupni sastav i tip humusa, kao i frakcioni sastav huminskih kiselina.

The effect of land use on group and fractional composition of humus was examined in 13 rendzina profiles under forests, 12 profiles under grassland and 8 profiles under arable fields in different parts of Serbia where rendzinas are typically found. The difference regarding land use of rendzina soils (depending on cultural practices or absence of any, and different amounts and quality of plant residues) under forest, grassland or arable fields had a highly significant statistical effect on humus group composition and the fractional composition of humic and fulvic acids. Human activities have brought about some positive changes regarding humus composition by promoting its stable component in rendzinas under grassland and arable fields, which is not the case in forest rendzina. The conversion of forests into grasslands and arable fields did not significantly affect the type of humus in rendzina soils, which remained characteristic of that soil type., Uticaj načina korišćenja zemljišta na grupni i frakcioni sastav humusa u rendzinama Srbije ispitivan je na 13 profila rendzine pod šumom (23 uzoraka), 12 pod travnjakom (18 uzoraka) i 8 pod njivom (16 uzoraka). Iz A horizonta uzet je jedan ili dva uzorka, zavisno od dubine, i po jedan uzorak iz prelaznog AC horizonta, u profilima koji su imali razvijen AC horizont. Razlike u načinu korišćenja zemljišta (primena ili odsustvo obrade i razlike u količini i kvalitetu biljnih ostataka) u rendzinama pod šumom, travom i njivom, statistički su značajno uticale na: grupni sastav humusa (značajno su bogatije fulvo kiselinama šumske nego rendzine pod travom, a rendzine pod travom sadrže značajno više humina nego šumske), frakcioni sastav huminskih kiselina (šumske rendzine sadrže značajno više frakcije 1 slobodnih huminskih kiselina i vezanih s mobilnim R2O3 nego rendzine pod travom i njivom) i frakcionom sastav fulvo kiselina (šumske rendzine sadrže značajno više frakcije 3 fulvo kiselina vezanih s huminskim kiselinama 3 u odnosu na njivske rendzine). Čovekova aktivnost dovela je do pozitivnih promena u sastavu humusa u pravcu povećanja stabilnog dela humusa u rendzinama pod travnjacima i njivama u poređenju sa šumskim rednzinama. Pretvaranje šuma u travnjake i njive nije značajno uticalo na tip humusa rendzina u Srbiji, koji je, kao što je poznato, a ovim istraživanjima potvrđeno, karakteristika tipa zemljišta.

Data on humus group and fractional composition in rendzina soils in Serbia acquired by the method of Pnomarieva and Plotnikova (PONOMAREVA and PLOTNIKOVA, 1968) are presented. The sites investigated in this study included: hillsides of Mt. Fruška Gora in Vojvodina; Topola and Aranđelovac environs in central Serbia; Jablanica basin and areas around Lajkovac and Valjevo in western Serbia; Sjenica-Pešter plateau in south-western Serbia; Negotin environs in eastern Serbia; and a stretch from Niš to Pirot in south-eastern Serbia. Humus was identified as belonging to the fulvate-humate type, and humification degree as medium or high. Fractional composition of humic acids is dominated by humic acids bound to Ca2+ (2), followed by those bound to clay and stable R2O3 (3), while free humic acids and those bound to mobile R2O3 (1) were found least represented. In the fractional composition of fulvic acids, the fraction bound to humic acids 2 was predominating, followed by fulvic acids bound to humic acids 3. Fulvic acids bound to humic acids 1 were found to be far less frequent, and the least so were free fulvic acids and those bound to mobile R2O3. A predomination of stable humus and the fulvate-humate humus type are the main characteristics of rendzina soils in Serbia., U ovom radu prikadani su podaci o grupnom i frakcionom sastavu humusa u rendzinama Srbije dobijeni metodom Pnomarjeve and Plotnjikove (PONOMAREVA and PLOTNIKOVA, 1968). Istraživanjima su obuhvaćena područja karakteristična za ovaj tip zemljišta: obronci Fuške gore u Vojvodini; okolina Topole i Aranđelovca u centralnoj Srbiji; sliv reke Jablanice i okolina Lajkovca i Valjeva u zapadnoj Srbiji; Sjeničko Pešterska visoravan u jugo-zapadnoj Srbiji, okolina Negotina u istočnoj Srbiji i potez Niš-Pirot u jugo-istočnoj Srbiji. Sadržaj huminskih kiselina varira u širokom intervalu, od 10.00 do 35.71%, a u prošeku iznosi 26.27%. Stepen humificiranosti Amo i Ap horizonata većine profila je srednji, a manjeg broja profila visok, a stepen humificiranosti AC horizonata je uglavnom srednji, u manjem broju profila nizak. Sadržaj fulvo kiselina varira u širokom intervalu od 26.40 do 55.09%, u prošeku iznosi 37.08%. Odnos huminskih i fulvo kiselina u Amo ili Ap horizontima varira od 0.38 do 1.06, a u AC horizontima od 0.25 do 0.76. U većini ispitivanih profila rendzina Srbije humus je fulvatno-humatnog tipa. Sadržaj nerastvornog ostatka je dosta visok, varira u širokom intervalu, od 16.34 do 51.58%, a u prošeku iznosi 36.95%. U frakcionom sastavu huminskih kiselina ispitivanih rendzina Srbije preovlađuje frakcija 2 - vezana sa Ca2+ (7.52-24.49%, u prošeku 13.78%); sledi frakcija 3 huminskih kiselina vezanih sa glinom i stabilnim R2O3 (l .89-15.82%, u prošeku 10.01%), a najmanje je zastupljena frakcija l huminskih kiselina slobodnih i vezanih sa mobilnim R2O3 (0.00-6.93%, u prošeku 2.19%). U frakcionom sastavu fulvo kiselina istraživanih rendzina Srbije najzastupljenija je (7.52-24.49%, u prošeku 13.78%) frakcija 2 fulvo kiselina -vezanih sa huminskim kiselinama 2, nešto manje je zastupljena (6.31-18.18%, u prošeku 12.37%) frakcija 3 fulvo kiselina - vezanih sa frakcijom 3 huminskim kiselinama. Udeo frakcije l fulvo kiselina - vezanih sa frakcijom l slobodnih huminskih kiselina je zn

The soil elemental analysis presented here focuses on humic acids in the Amo and Ap horizons of 16 profiles in different parts of Serbia that are characteristic of rendzina soils. The mass fraction of C in humic acids of rendzina soils in Serbia ranges from 50.33% to 56.81%, with the average of 52.34%. The mass fraction of H in humic acids of all investigated rendzina profiles was found to vary between 4.28% and 5.81%, and the average was 5.18%. The corresponding fraction of N was 3.34-4.96%, or 4.06% on the average. The mass fraction of O in the studied rendzina humic acids ranged from 33.81% to 39.88%, and was 38.42% on the average. The atomic C of humic acids in all renzdinas studied varied between 33.61% and 38.79%, and was 35.81% on the average. The atomic fraction of H varied between 37.38% and 45.13%, or the average 42.08%. Oxygen content in humic acids was found to be 17.11-21.69%, or 19.73% on the average, while nitrogen content was 2.02-2.83%, or the average 2.38%. The H:C ratio in humic acids was found to vary from 0.96 to 1.32, being 1.18 on the average, while the C:N ratio was 12.06-18.43, or the average 15.21. The results of this elemental analysis show that the humic acids of Serbian rendzina soils are characterized by a medium degree humification and condensation, which is consistent with the fulvate-humate type of humus in that soil., Istraživanja elementarnog sastava huminskih kiselina rendzina Srbije imala su za cilj određivanje stepena humificiranosti i kondenzacije huminskih kiselina, a sve u svrhu proširivanja znanja o uslovima obrazovanja i evolucije ovog nedovoljno proučenog tipa zemljišta u Srbiji. Rezultati ispitivanja elementarnog sastava prikazani u ovom radu odnose se na huminske kiseline (19 preparata) iz Amo i Ap horizonta 16 profila rendzine sa različitih područja Srbije karakterističnih za ovaj tip zemljišta. Maseni udeo C u huminskim kiselinama u rendzinama Srbije kreće se od 50.33 do 56.81%, a u prošeku iznosi 52.34%. Maseni udeo H u huminskim kiselinama u svim ispitivanim profilima rendzina varira od 4.28 do 5.81%, a u prošeku iznosi 5.18%. Maseni udeo N u huminskim kiselinama rendzina varira od 3.34 do 4.96%, a u prošeku iznosi 4.06%. Maseni udeo O u huminskim kiselinama rendzina varira od 33.81 do 39.88%, a u prošeku iznosi 38.42%. Atomski udeo C u huminskim kiselinama, u rendzinama u celini, varira od 33.61 do 38.79%, a u prošeku iznosi 35.81%. Atomski udeo H varira od 37.38 do 45.13%, a u prošeku iznosi 42.08%. Kiseonika huminske kiseline rendzina sadrže 17.11-21.69%, prosečno 19.73%, dok sadržaj azota varira 2.02-2.83%, a u prošeku iznosi 2.38%. Odnos H:C u huminskim kiselinama varira od 0.96 do 1.32, a u prošeku iznosi 1.18, a odnos C:N varira od 12.06 do 18.43, i u prošeku iznosi 15.21. Rezultati elementarne analize pokazuju da su huminske kiseline rendzina Srbije srednjeg stepena humifikovanosti i kondenzacije što je u korelaciji sa fulvatno-humatnim tipom humusa ovog tipa zemljišta.

Rendzina is a widespread soil type in Serbia that can be found in several stages of evolutionary development and put to different land uses. Our objective was to investigate the effect of decarbonation of rendzina soils in Serbia and several land use variants on humus content and its enrichment in nitrogen. Humus content is mostly high, and rarely medium, in the A horizon of calcaric forest rendzinas; medium or high under grassland, and very low under arable land. In non-calcaric forest rendzinas, humus content in horizon A is medium or low; under grassland it is low and very low, and under arable land again low and very low. Rendzinas are predominantly rich and very rich in total nitrogen in the uppermost layer of horizon A, and medium or well supplied in the layer below it. Enrichment of humus in nitrogen, shown as the C:N ratio, is mostly medium, and rarely low. Decarbonation was caused by decreasing humus content and total nitrogen in soil, while the enrichment of humus in nitrogen (C:N ratio) showed no significant change. Different land uses were found to have significant effect on decreasing humus and total nitrogen contents in rendzinas under grassland, and especially arable land, compared to forest rendzinas, while humus enrichment in nitrogen was significantly higher in rendzinas underlying grassland than forest. ., Rendzina je veoma rasprostranjen tip zemljišta u Srbiji u području brdsko-planinskog reljefa, nalazi se u više evolucionih stadijuma razvoja i koristi se na različite načine, odnosno, nalazi se pod različitim biljnim pokrivačima. Cilj našeg rada je zato bio ispitivanje uticaja procesa izluživanja i različitog načina korišćenja zemljišta tipa rendzina u Srbiji na sadržaj humusa i njegovu obezbeđenost azotom. Sadržaj ukupnog C u ispitivanim rendzinama Srbije varira od 1.15 do 6.25%, a u proseku iznosi 3.25%. Sadržaj humusa u A horizontu karbonatnih šumskih rendzina je uglavnom visok, ređe srednji; pod travnjacima srednji ili visok, a pod njivama veoma nizak. U izluženim šumskim rendzinama sadržaj humusa u A horizontu je srednji ili nizak; pod travnjacima nizak i veoma nizak, a u njivskim, takođe, nizak i veoma nizak. Sadržaj ukupnog azota varira u širokom intervalu, od 0,123 do 0.570%, a u proseku iznosi 0.317%; stoga su rendzine pretežno bogato i veoma bogato obezbeđene ukupnim azotom u površinskom delu A horiznonta, a u potpovršinskom obezbeđene su srednje ili dobro. Obezbeđenost humusa azotom, izražena preko odnosa C:N, uglavnom je srednja, a ređe niska. Odnos C:N kreće se od 8.09 do 16.54, a u proseku iznosi 10.09. Procesi izluživanja (ispiranje CaCO3, niži pH i stepen zasićenosti bazama) u zemljištima tipa rendzina u Srbiji uslovili su smanjenje sadržaja humusa i ukupnog azota, pri čemu se obezbeđenost humusa azotom (odnos C:N) nije značajno promenila. Razlike u načinu korišćenja zemljišta (primena ili odsustvo obrade i razlike u količini i kvalitetu biljnih ostataka) statistički su značajno uticale na smanjenje sadržaja humusa i ukupnog azota u rendzinama pod travnjacima i naročito njivama u poređenju sa šumskim rendzinama, dok je obezbeđenost humusa azotom značajno veća u travnjačkim u poređenju sa šumskim rendzinama. .

This study aimed to quantify structural properties of rendzina soils in Serbia, and especially to determine the effect of decarbonation and different forms of land use on soil aggregate ditribution and stability. An indication of favourable soil aggregate distribution is data showing that the content of aggregates with 1-5 mm particle size, which is desirable from the agronomical viewpoint, is 50.04% on the average, while macroaggregates make 6.28-fold the sum of micro and mega aggregates. High aggregate stability is indicated by the fact that the proportion of water stable aggregates of >1 mm size ranges from 53.78 to 91.38%, i.e. 71.38% on the average. With increasing alkalinity of calcaric rendzina soils, aggregate stability in water significantly decreases. Concerning non-calcaric rendzina soils, the proportion of fine aggregates increases as the process of decarbonation proceeds and their stability decreases. Differences in aggregate distribution and stability bewteen the calcaric and non-calcaric rendzina soils were not found to be statistically significant. Forest and grassland rendzinas showed no significant difference regarding structural properties. Soil tillage has significant effect on the soil structure of arable rendzinas and, compared to forest and grassland rendzinas, they have less favorable structure index and water stable aggregate content. ., Renzina je tip zemljišta veoma rasprostranjen u Srbiji, a podaci o njenim strukturnim osobinama su samo opisni. Struktura zemljišta je veoma važna osobina koja utiče na mnoge biološke i fizičke procese u zemljištu. Cilj ovog rada bio je da utvrđivanje kvantitativnih podataka o strukturnim osobinama rendzina u Srbiji, posebno uticaja procesa izluživanja i različitih načina korišćenja zemljišta (šuma, travnjaci i njive) na veličinu i stabilnost strukturnih agregata. Veličina strukturinih agregata u rendzinama je veoma povoljna o čemu svedoče podaci da sadržaj, s agronomske tačke poželjne frakcije veličine 1-5 mm, u proseku iznosi 50.04%, a makroagregata ima 6.28 puta više u odnosu na zbir mikro i megaagregata. O visokoj otpornosti strukturnih agregata u vodi govori podatak da su vodootporni strukturni agregati veći od 1 mm zastupljeni sa 53.78 do 91.38%, a u proseku sa 71.38%. S povećanjem alkalnosti karbonatnih rendzina značajno se smanjuje vodootpornost strukturnih agregata. Unutar izluženih rendzina s napredovanjem procesa izluživanja dolazi do povećanja udela sitnijih strukturnih agregata i smanjenja njihove otpornosti prema vodi. Razlike u distribuciji i stabilnosti strukturnih agregata između karbonatnih i izluženih rendzina nisu statistički značajne, što je i logično s obzirom da su procesi izluživanja uticali na snižavanje pH zemljišta, ali je ono i dalje ima visok stepen zasićenosti bazama, naročito Ca2+ koji je, kao što je poznato, jedan od najznačajnijih koagulatora odgovornih za obrazovanje strukturnih agregata i njihovu stabilnost. Šumske i travnjačke rendzine ne razlikuju se značajno po strukturnim osobinama. Obrada zemljišta značajno je uticala na strukturu njivskih rendzina, tako da one u poređenju sa šumskim i travnjačkim imaju nepovoljniji koeficijent strukturnosti i manju stabilnost strukturnih agregata. Obrada zemljišta, pored direktnog usitnjavanja strukturnih agregata, na strukturu utiče i indirektno menjanjem temperature, vlage i aeracije i time

The present investigation of textures of rendzina soils in Serbia is part of a more comprehensive research into effects of decarbonation and different land uses on physical and chemical characteristics of that widespread soil type in Serbia. Geological parent material was found to have a predominant influence on the texture of rendzina soils. Rendzinas on sandy marl were found to be heavily skeletoidal and skeletoidal sandy loams or skeletoidal clay loams in A horizon and skeletal sandy loams or heavily skeletoid sandy-clay loams in AC horizon. Rendzinas on calcareous gravel are skeletoidal clay loams in A horizon, skeletoidal sandy loams in AC horizon and heavily skeletal sandy loams in C horizon. Rendzinas on unindurated limestone are slightly skeletoidal loams or skeletoidal clay loams. The rendzinas on marl and marly or unindurated limestone are mostly slightly to heavily skeletoidal light clays. Differences in texture between calcaric and non-calcaric soils (the latter containing less skeletal material, i.e. stone and especially gravel, and more clay) were not found statistically significant. Skeletal quality increases with solum depth in non-calcaric rendzinas, and the fine earth fraction has a heavier texture, in contrast to calcaric rendzinas, where the situation is highly heterogenous. Rendzinas under forests were found to be significantly more skeletal than those under grassland and arable land. Little difference in texture was observed in rendzinas under grassland and arable land. ., Ispitivanja mehaničkog sastava u zemljištu tipa rendzina u Srbiji, prikazana u ovom radu, deo su širih istraživanja čiji je cilj bio utvrđivanje uticaja procesa izluživanja i različitog načina korišćenja zemljišta na fizičke i hemijske osobine tog veoma rasprostranjenog tipa zemljišta u Srbiji. U tom smislu, istraživanjima su obuhvaćeni različiti delovi Srbije: Vojvodina - obronci Fruške gore, Šumadija (Topola-Aranđelovac), zapadna Srbija (sliv reke Jablanice, okolina Lajkovca i Valjeva), jugo-zapadna Srbija (Sjeničko-pešterska visoravan), istočna Srbija (okolina Negotina) i jugoistočna Srbija (Niš-Pirot). Terenskim istraživanjima je bilo obuhvaćeno ukupno trideset reprezentativnih profila, od 24 profila karbonatnih rendzina (9 pod šumom, 9 pod travnjakom i 6 pod njivom) i 6 profila izlužene (3 pod šumom, 2 pod travnjakom i 1 pod njivom). Ukupno 51 uzoraka zemljišta iz A ili AC horizonata (ako je razvijen) je analizirano. Preovlađujući uticaj na mehanički sastav ispitivanih rendzina ima geološki supstrat na kojem su obrazovane. Rendzine na peskovitim laporcima su jako skeletoidne i skeletoidne peskovite ilovače ili skeletoidne glinaste ilovače u A horizontu i skeletne peskovite ilovače ili jako skeletoidne peskovito-glinaste ilovače u AC horizontu. Rendzine na karbonatnom šljunku su skeletoidne glinaste ilovače u A horizontu, skeletoidne peskovite ilovače u AC horizontu, a C horizont jako skeletna peskovita ilovača. Rendzine na mekanim krečnjacima su slabo skeletoidne ilovače ili skeletoidne glinaste ilovače. Rendzine na laporcima, laporovitim ili mekanim krečnjacima, su uglavnom slabo do jako skeletoidne lake glinuše. Razlike u mehaničkom sastavu između karbonatnih i izluženih rendzina (izlužene rendzine sadrže manje skeleta: kamena, a naročito šljunka, i više gline) nisu statistički značajne. U izluženim rendzinama sa dubinom soluma povećava se skeletnost zemljišta, a sitne frakcije zemljišta su težeg mehaničkog sastava, za razliku od karbonatnih rendzina gde je s

Humus content and its properties on five locations in Sjenica region are studied and results obtained are presented in this paper. Humus content is high in all the soil types investigated. Total fulvic acids are predominant over total humic acids. Fraction of free humic acids bounded with mobile R2O3 is dominant in comparison with other humic acids fractions. Content of fulvic acid fraction bounded with free humic acids is higher when it is compared with other fulvic acids fractions. On two locations with the same type of soil under natural and cultivated grassland, there are not differences in humus content and composition between natural and cultivated grassland., U radu je prikazano stanje humusa u zemljištima pod prirodnim i sejanim travnjacima na lokalnostima Rasno, Donja Vapa, Čedovo, Kladnica i Brnjica na području Sjenice. Proučavana zemljišta su dobro do jako humozna. Stepen humifikovanosti organske materije je srednji pod prirodnim, a nizak do srednji pod sejanim travnjacima. Analizovani uzorci kod svih tipovi zemljišta pod prirodnim i sejanim travnjacima pripadaju fulvatnom tipu humusa. Među huminskim kislinama preovlađuje frakcija slobodnih huminskih kiselina i povezanih sa mobilnim R2O3, a među fulvokiselinama frakcija vezana za slobodne huminske kiseline. Kod dve lokalnosti, gde su prirodni i sejani travnjaci zastupljeni na istom tipu zemljišta, nema značajnijih razlika u sadržaju, grupnom i frakcionom sastavu humusa između prirodnih i sejanih travnjaka.

Investigation of terra rossa soils at wild pyrethrum habitats was carried out to provide more data and deepen our understan­ding of the species' requirements regarding soil and other ecological factors. Pyrethrum flowers contain pyrethrines, a complex of different compounds with insecticidal properties, which are safe both to humans and the environment. Wild pyrethrum growing on terra rossa soils was found at sites above Lake Skadar and on the southern parts of Cape Trsteno. The main properties of terra rossa at wild pyrethrum habitats in Montenegro are closely related with the character of lime­stone parent rocks and karst declining relief, and they include pronounced rocky surface, very shallow to medium deep solum and limestone coarse fragments in the topsoil of some profiles, which makes the soil permeable for water and rather dry, while the depth at which plants can take root is limited to the top layer of some 20 cm. Humus horizons of terra rossa are neutral to slightly alkaline, while cambic horizons are medium acid to neutral. Humus content in the soil is low, high and very high, the content of total nitrogen is high, available K2O is found in low, medium and high content, while available phosphorus can be found in traces alone. The content of available Zn, Mn, Cu and Fe is very high. ., Istraživanja crvenica kao prirodnih staništa buhača imala su za cilj detaljnije upoznavanje sa zahtevima ove biljne vrste za ekološkim, a među njima i zemljišnim činiocima. Cvet buhača sadrži piretrine - kompleks različitih jedinjenja koja imaju insekticidna svojstva, a istovremeno su bezopasna po čoveka i okolinu. Prirodna staništa buhača na crvenicama smeštena su iznad Skadarskog jezera, na severnim padinama brda Vršuta i Ornije, i na južnim stranama rta Trsteno. Osnovno obeležje crvenicama, kao staništu samoniklog buhača u Crnoj Gori, daju krečnjačka matična stena i kraški padinski reljef - izraženu stenovitost površine, veoma plitak do srednje dubok solum i skeletnost u površinskim delovima nekih profila, zbog čega je zemljište propusne za vodu i suvo, a prostor za ukorenjavanje biljaka ograničen na površinskih dvadesetak centimetara. Humusni horizonti su neutralni i slabo alkalni, a kambični srednje kiseli do neutralni. Zemljišta su slabo, dosta i jako humozna, dobro obezbeđene ukupnim azotom, slabo, srednje i dobro obezbeđene lako mobilnim formama K2O, lako mobilnog fosfora sadrže samo u tragovima, a lako mobilnim Zn, Mn, Cu i Fe su veoma dobro je obezbeđena.

To gain a better knowledge of mining areas and potential remediation processes, some characteristics (morphological, physical, chemical and microbiological) of soils formed on open-pit Cu mine waste (OPW) and Cu post-flotation tailings (PFT) dumps were investigated. Soil profiles and surface samples were studied. In general, the investigated soils are characterized by large proportion of coarse soil particles, degraded structure, low humus content, low pH, high As and Cu concentrations, and low soil microbial activity. In all investigated profiles there is no recognizable topsoil layer containing in situ formed humus probably due to soil age, lack of plant cover and organic litter, as well as other unfavorable soil conditions. The specificity of investigated soils is an irregular distribution of some soil characteristics (porosity, humus content, microbiological activity) over depth, which is a result of their technogenic origin. By establishing correlations between the studied surface sample parameters, using principal component analysis (PCA), poorer aggregate properties of PFT than of OPW soils were found, resulting most likely from aggressive mining, i.e., flotation processes. Both OPW and PFT soils compared with control natural soils are characterized by lower clay and humus content, and poorer aggregate properties.

Humic acids (HAs), similar to other fractions of humic substances (HSs), have a large number of reactive functional groups enabling them to aggregate in solutions. Regardless of the origin of humic acid (aqueous or soil), this aggregation process is dependent on environmental conditions and strongly influences the mobility of soluble ionic and molecular pollutants. The aim of this work was to monitor the aggregation process of two humic acids isolated from different mineral soils (IHSS Elliot soil HA standard and Rendzic Leptosol HA) in the 2-11 pH range. Changes in aggregate size in HA sols were followed up using dynamic light scattering (DLS), while zeta potential (ZP) measurements in the same pH range were performed applying laser Doppler electrophoresis (LDE) technique. The effect of HA sol concentration and soil source on aggregation was examined as well. Besides, HA samples were characterized using Fourier transform infrared (FT-IR) spectroscopy. By inspecting HA-particle-size dependence on pH, it can be concluded that both HAs in corresponding sols behave as molecular aggregates or supramolecular structures, formed from small individual moieties (sizes lt 10 nm) at higher pH values. The ZP vs. pH curve for both HAs revealed the ZP minimum in the 5-7 pH range, caused most likely by dissociation of acidic functional groups prevailing at lower pH values and deaggregation predominating over dissociation at higher pH values.

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 Mačva and Pocerina. The humus content was determined by dichromate method, and humus components were measured using the method proposed by Kononova and Belcikova. 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 humus 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., Cilj ovog rada je ispitivanje uticaja dva podtipa pseudogleja (ravničarskog i obronačnog) i tri načina korišćenja (šuma, travnjak, njiva) na sadržaj i grupno-frakcioni sastav humusa na području južne Mačve i Pocerine. Ispitivana zemljišta generalno karakteriše uglavnom nizak sadržaj humusa. Statistički značajno je sadržaj humusa veći u ravničarskom podtipu pseudogleja u poređenju sa obronačnim. U pseudogleju pod travnom vegetacijom i na obradivim površinama došlo je do statistički značajnog smanjenja sadržaja humusa u poređenju sa pseudoglejom pod šumom. Bitna karakteristika grupno-frakcionog sastava humusa površinskog horizonta je dominacija fulvo nad huminskim kiselinama. Ravničarski pseudoglej sadrži statistički značajno više huminskih kiselina. Sastav humusa se značajno razlikuje u pseudogleju pod šumom u poređenju sa pseudoglejom pod travom i njivom: sadrži više fulvo kiselina, a manje humina i ima uži Ch:Cf odnos. Promena načina korišćenja pseudogleja dovela je do poboljšanja osobina humusa, odnosno donekle dovela do stabilizacije humusa i umanjila njegove inače veoma loše osobine.

The systematic survey of grassland communities was performed on Mt. Stol (eastern Serbia). The main aims of the research were to: (1) determine grassland vegetation types of the researched area; (2) correlate the impacts of the soil and environmental conditions on the occurrence of certain plant communities, and (3) comment on the conservational value of the grasslands in the researched area. The data set included 60 phytosociological relevés of grasslands recorded between 2001 and 2004. The main environmental gradients of species composition were analyzed by Detrended Correspondence Analysis (DCA). For the ecological interpretation of ordination axes, ecological indicator values were used. Three associations were distinguished: Danthonietum calycinae, Asperulo-Agrostietum vulgaris and Ranunculo bulbosi- Arrhenatheretum elatioris belonging to two alliances and two classes: Chrysopogono-Danthonion - Festuco-Brometea and Arrhenatherion - Molinio-Arrhenatheretea. The results of the DCA support our assumption that the main environmental gradient in the species composition of the grasslands is related to nutrients and moisture. The conservational value of grasslands in the researched area is discussed.

Bentonite samples from Petrovac and Aleksinac were treated with sulfuric acid of different molarities. Differences in structure and texture of the initial and modified bentonite were determined by chemical analysis and Xraypowder diffraction (XRPD), infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and physisorption nitrogen at -196°C. Sulfuric acid caused an exchange of Al3+, Fe3+ and Mg2+ with H+ ions which led to a modification of the smectite crystalline structure. The Mg and Fe substitution in the octahedral sheet promoted the dispersion of those layers and forming of amorphous silicon. The sequence according to which the cations left the octahedral sheets was as follows: Mg2+>Fe3+>Al3+. The sulfuric acid activated bentonites exhibiting a lower cation exchange capacity (CEC) and a change of specific surface area (SBET) from 6 to 387 for bentonite from Petrovac and from 44 to 1784 m2 g-1 for bentonite from Aleksinac, positioning them as an excellent absorber in wine technology and in the protection of soil and environment., Uzorci bentonita iz Petrovca i Aleksinca tretirani su različitim molaritetima sumporne kiseline. Promene u strukturi i teksturi polaznih i modifikovanih bentonita utvrđene su hemijskom i analizom rendgenske difrakcije praha X-zraka (XRPD), infra crvenom spektroskopijom (FTIR), skening elektronskom mikroskopijom (SEM) i fizisorpcijom azota na -196°C. Dejstvo H2SO4 kiseline izazvalo je zamenu Al3+, Fe3+ i Mg2+ sa H+ jonima što je dovelo do modifikacije kristalne strukture smektita. Supstitucija Mg i Fe u oktaedarskom listu smektita promovisala je raspuštanje tih slojeva i formiranje silikatne faze. Redosled kojim su ovi katjoni napuštali oktaedarske listove bio je sledeći: Mg2+>Fe3+>Al3+. Sumpornom kiselinom aktivirani bentoniti pokazali su niži kapacitet katjonske izmene (CEC) i promenu specifične površine (SBET), od 6 na 387 kod bentonita Petrovca i od 44 na 1784 m2 g-1 kod bentonita Aleksinca, što ih svrstava u odlične absorbente u tehnologiji vina, zaštiti zemljišta i životne sredine.

Goal, Scope and BACKGROUND: . During the Balkan conflict in 1999, soil in contaminated areas was enriched in depleted uranium (DU) isotopic signature, relative to the in-situ natural uranium present. After the military activities, most of kinetic DU penetrators or their fragments remained buried in the ground in certain geomorphological and geochemical environments exposed to local weathering conditions. The contamination distribution, mobility and/or fixation of DU in the contaminated soil profile at one hot spot were the subject of our study. The results should disclose what happened with released DU corrosion products in three years elapsed, given the scope of their geochemical fractionation, and mark out the most probable host substrates in investigated soil type. Methods. Gamma-spectrometric analysis of soil samples taken in the DU penetrator impact-zone was done to obtain present contamination levels. Set of samples is subjected to five-step and three-step sequential extraction procedures, specifically selective to different physical/chemical associations in soil. The stable elements are determined in extracts by the atomic absorption spectroscopy. After the ion-exchange based uranium separation procedure, alpha-spectrometric analysis of obtained fractions was done and DU distribution in five extraction phases found from U-235/U-238 and U-234/U-238 isotopic ratios. Results. Depleted uranium concentration falls down to the 1% of the initial value, at approximately 150 mm distance to the source. Carbonates and iron/manganese hydrous oxides are indicated as the most probable substrates for depleted uranium in the characterized soil type. Therefore, in the highly contaminated soil samples, depleted uranium is still weakly bonded and easy exchangeable. The significant levels of organic-bonded depleted uranium are found in surface soil only. Discussion. Dependence of the fractionation on the contamination levels is evident. Samples with higher DU contents have shown