18 research outputs found
The effect of soil chemical and phisical properties on soil plasticity
Na tri razliÄita tipa tla (aluvijalno, lesivirano i ritska crnica) utvrÄen je utjecaj kemijskih i fizikalnih svojstva oraniÄnih horizonata na plastiÄnost tla. Vrlo znaÄajnu korelaciju pozitivnog smjera sa plastiÄnoÅ”Äu pokazali su humus, glina, KIK, sitni prah, magnezij, natrij i kalcij dok su vrlo znaÄajnu korelaciju ali negativnog smjera pokazali hidrolitiÄka kiselost, krupni pijesak, sitni pijesak i krupni prah. StatistiÄkom obradom podataka utvrÄene su statistiÄki znaÄajne razlike izmeÄu svih istraživanih tipova tala i to za glinu, volumnu gustoÄu tla i za gustoÄu pakiranja, te za aktualnu i supstitucijsku kiselost, kationski izmjenjivaÄki kapacitet tla te sadržaj kalcija. TakoÄer, utvrÄene su statistiÄki znaÄajne razlike izmeÄu istraživanih tala za donju granicu plastiÄnosti, za gornju granicu plastiÄnosti i za indeks plastiÄnosti. ProsjeÄna utvrÄena vrijednost donje granice plastiÄnosti kao važnog elementa za odreÄivanje trenutka obrade tla iznosila je 18,90 % na aluvijalnom tlu, 24,06 % na lesiviranom tlu, dok je na ritskoj crnici iznosila 28,6 %.In three different soil types (fluvisol, luvisol and humic gyesol), the influence of chemical and physical properties of the arable horizons on the soil plasticity was determined. Highly significant positive correlation was determined between plasticity and humus, clay, CEC, small dust particles, magnesium, sodium and calcium, while significatly negative correlation was shown was shown for palsticity with hydrolytic acidity, large sand, fine sand and larger dust particles. Statistical data analysis revealed statistically significant differences in clay, soil density and packing density, and for current and substituent acidity, cation exchange capacity of soil and calcium content, between all the examined types of soil. Also, statistically significant differences were found between soils examined for the lower limit of plasticity, the upper plasticity limit and for the plasticity index. The average value of the lower limit of plasticity, as an important element for determining the ideal time for soil tillage, was 18.90% on fluvisol soil, 24.06% on the luvisol soil, while in the humic gyesol soil that value was 28.6%
RADNI DIJAGRAM I UTJECAJ PARAMETARA ISPITIVANJA NA REZULTATE VLAÄNIH ISPITIVANJA
Tensile steel-coupon testing qualifies as one of the more commonly used experiments for determination of basic parameters for structural design. Such tests are usually performed to determine technical stressāstrain relationships of tested materials. Technical stressāstrain curves are not suitable for various numerical material models that exploit the plastic region of behavior, owing to the necking effect and accompanying change in coupon area being neglected during stress determination. Material ductility is influenced by the choice of gauge length, which may cause different researchers to differently interpret coupon tests of the same material. The proposed research utilizes benefits offered by an optical system for deformation monitoring to track changes in surface area and implement them during stress calculations until fracture. The possibility of adjusting the gauge length the same sample the ability to study its effect on obtained results. Based on analyzed data, these influences were evaluated and possible errors identified.VlaÄno ispitivanje ÄeliÄnih epruveta je jedan od ÄeÅ”Äih eksperimenata, za praktiÄne i znanstvene svrhe, prvenstveno jer daje osnovu za odreÄivanje baznih varijabli koje su potrebne prilikom dimenzioniranja. UobiÄajeni rezultat vlaÄnog ispitivanja je tehniÄki radni dijagram naprezanje - relativna deformacija. MeÄutim, on nije pogodan za razliÄite numeriÄke modele materijala pomoÄu kojih se iskoriÅ”tava plastiÄno podruÄje ponaÅ”anja, vezano uz Äinjenicu da se uÄinak suženja i pripadne promjene povrÅ”ine popreÄnog presjeka epruvete zanemaruju pri odreÄivanju naprezanja. Duktilnost je pod utjecajem odabrane mjerne duljine, Å”to kao posljedicu može imati da razliÄiti istraživaÄi tumaÄe rezultate vlaÄnog ispitivanja istog materijala na razliÄite naÄine. Provedeno istraživanje iskoriÅ”tava prednosti optiÄkog sustava za prostorno snimanje deformacija, tako da se prate promjene ploÅ”tine popreÄnog presjeka i uzimaju u obzir pri proraÄunu naprezanja, sve do loma. MoguÄnost promjene mjerne duljine na uzorku omoguÄila je prouÄavanje tog uÄinka na rezultate. Na temelju analize dobivenih podataka, navedeni utjecaji su procijenjeni i utvrÄene su moguÄe pogreÅ”ke
Testing a prestressed concrete shell subjected to long-term loading and unloading
Prikazani su rezultati eksperimentalnog ispitivanja cilindriÄne prednapete betonske ljuske dugotrajnim optereÄenjem i rastereÄenjem. Ljuska je armirana mrežom u gornjem i donjem podruÄju, s razliÄitom ploÅ”tinom armature u dva smjera i s dva ravna prednapeta uzdužna kabela. Oslonjena je samo u uglovima, sa sprijeÄenim boÄnim pomacima. Mjereni su pomaci ljuske, te deformacije betona, klasiÄne armature i kabela u viÅ”e toÄaka kroz godinu i pol od prednapinjanja i optereÄenja.Results obtained by testing a cylindrical prestressed concrete shell subjected to long-term loading and unloading are presented. The shell is reinforced with steel fabric in the top and bottom zones, and features different reinforcement areas in two directions, as well as two straight prestressed longitudinal cables. It is attached at angles only, and lateral displacements are restrained. Shell displacements, and deformation of concrete in the zone of traditional reinforcement and cables, were measured at several points over one and a half year period following the initial prestressing and loading
Influence of physical and chemical properties of different soil types on optimal soil moisture for tillage
PlastiÄnost je tla podruÄje konzistencije tla, odnosno predstavlja promjenu stanja tla zbog razliÄite vlažnosti tla djelovanjem vanjskih sila. Konzistencija odreÄuje veliÄinu otpora koje tlo pruža pri obradi, stoga je cilj istraživanja utvrditi optimalno stanje vlažnosti tla za obradu te utjecaj fizikalnih i kemijskih svojstva oraniÄnih horizonata na plastiÄnost tla, kao jednog od svojstava konzistencije. Istraživanje je provedeno na tri razliÄita tipa tla: aluvijalnome, lesiviranome te na ritskoj crnici. UtvrÄene su statistiÄki znaÄajne razlike izmeÄu svih istraživanih tipova tala i to za sadržaj Äestica gline, gustoÄu pakiranja, aktualnu i supstitucijsku kiselost, kationski izmjenjivaÄki kapacitet tla te sadržaj kalcija. TakoÄer, utvrÄene su statistiÄki znaÄajne razlike izmeÄu istraživanih tipova tala za donju granicu plastiÄnosti, gornju granicu plastiÄnosti te indeks plastiÄnosti. ProsjeÄna utvrÄena vrijednost donje granice plastiÄnosti, kao važnog elementa za odreÄivanje optimalnoga trenutka obrade tla, iznosila je 18,9% mas. na aluvijalnome tlu, 24,0% mas. na lesiviranome tlu, dok je na ritskoj crnici iznosila 28,6% mas. Vrlo znaÄajnu korelaciju pozitivnoga smjera s granicama plastiÄnosti pokazali su humus, glina, KIK, sitni prah, magnezij, natrij i kalcij, dok su vrlo znaÄajnu korelaciju, ali negativnoga smjera, pokazali hidrolitiÄka kiselost, krupni pijesak, sitni pijesak i krupni prah. Kreiranim regresijskim modelima može se procijeniti optimalno stanje vlažnosti tla za obradu na temelju osnovnih svojstava tala. Preciznost modela znaÄajno se poveÄava uvoÄenjem veÄega broja fizikalnih i kemijskih svojstva tla, a dopunsku preciznost modela mogu poveÄati podatci o tipu tla.Soil plasticity is the area of soil consistency, i.e. it represents a change in soil condition due to different soil moisture influenced by external forces activity. Consistency determines soil resistance in tillage, therefore, the aim of the research was to determine the optimum soil moisture condition for tillage and the influence of the chemical and physical properties of the arable land horizons on the soil plasticity on three different types of soil (fluvisol, luvisol and humic glaysol). Statistically significant differences were found between all examined soil types, such as the content of clay particles, the density of packaging and the actual and substitution acidity, the cation exchange capacity and the content of calcium. There were also statistically significant differences between the examined types of soil for the plasticity limit, liquid limit and the plasticity index. The average established value of plasticity limit as an important element for determining the optimal moment of soil tillage was 18.9% mass on fluvisol, 24.0% mass on luvisol and 28.6% mass on humic glaysol. Very significant positive direction correlation with plasticity limits was shown by organic matter, clay, fine silt, magnesium, sodium and calcium, while very significant negative direction correlation was shown by hydrolytic acidity, coarse sand, fine sand and coarse silt. Created regression models can estimate the optimal soil moisture condition for soil cultivation based on the basic soil properties. The model precision is significantly increased by introducing a greater number of agrochemical and agrophysical soil properties, and the additional precision of the model can be increased by soil type data
Influence of physical and chemical properties of different soil types on optimal soil moisture for tillage
PlastiÄnost je tla podruÄje konzistencije tla, odnosno predstavlja promjenu stanja tla zbog razliÄite vlažnosti tla djelovanjem vanjskih sila. Konzistencija odreÄuje veliÄinu otpora koje tlo pruža pri obradi, stoga je cilj istraživanja utvrditi optimalno stanje vlažnosti tla za obradu te utjecaj fizikalnih i kemijskih svojstva oraniÄnih horizonata na plastiÄnost tla, kao jednog od svojstava konzistencije. Istraživanje je provedeno na tri razliÄita tipa tla: aluvijalnome, lesiviranome te na ritskoj crnici. UtvrÄene su statistiÄki znaÄajne razlike izmeÄu svih istraživanih tipova tala i to za sadržaj Äestica gline, gustoÄu pakiranja, aktualnu i supstitucijsku kiselost, kationski izmjenjivaÄki kapacitet tla te sadržaj kalcija. TakoÄer, utvrÄene su statistiÄki znaÄajne razlike izmeÄu istraživanih tipova tala za donju granicu plastiÄnosti, gornju granicu plastiÄnosti te indeks plastiÄnosti. ProsjeÄna utvrÄena vrijednost donje granice plastiÄnosti, kao važnog elementa za odreÄivanje optimalnoga trenutka obrade tla, iznosila je 18,9% mas. na aluvijalnome tlu, 24,0% mas. na lesiviranome tlu, dok je na ritskoj crnici iznosila 28,6% mas. Vrlo znaÄajnu korelaciju pozitivnoga smjera s granicama plastiÄnosti pokazali su humus, glina, KIK, sitni prah, magnezij, natrij i kalcij, dok su vrlo znaÄajnu korelaciju, ali negativnoga smjera, pokazali hidrolitiÄka kiselost, krupni pijesak, sitni pijesak i krupni prah. Kreiranim regresijskim modelima može se procijeniti optimalno stanje vlažnosti tla za obradu na temelju osnovnih svojstava tala. Preciznost modela znaÄajno se poveÄava uvoÄenjem veÄega broja fizikalnih i kemijskih svojstva tla, a dopunsku preciznost modela mogu poveÄati podatci o tipu tla.Soil plasticity is the area of soil consistency, i.e. it represents a change in soil condition due to different soil moisture influenced by external forces activity. Consistency determines soil resistance in tillage, therefore, the aim of the research was to determine the optimum soil moisture condition for tillage and the influence of the chemical and physical properties of the arable land horizons on the soil plasticity on three different types of soil (fluvisol, luvisol and humic glaysol). Statistically significant differences were found between all examined soil types, such as the content of clay particles, the density of packaging and the actual and substitution acidity, the cation exchange capacity and the content of calcium. There were also statistically significant differences between the examined types of soil for the plasticity limit, liquid limit and the plasticity index. The average established value of plasticity limit as an important element for determining the optimal moment of soil tillage was 18.9% mass on fluvisol, 24.0% mass on luvisol and 28.6% mass on humic glaysol. Very significant positive direction correlation with plasticity limits was shown by organic matter, clay, fine silt, magnesium, sodium and calcium, while very significant negative direction correlation was shown by hydrolytic acidity, coarse sand, fine sand and coarse silt. Created regression models can estimate the optimal soil moisture condition for soil cultivation based on the basic soil properties. The model precision is significantly increased by introducing a greater number of agrochemical and agrophysical soil properties, and the additional precision of the model can be increased by soil type data
Occupational diseases and general practitioners
Cilj ovog istraživanja je istražiti miÅ”ljenja lijeÄnika obiteljske medicine o prijavljivanju profesionalnih bolesti, moguÄoj povezanosti radnog statusa, bolovanja i ocjene radne sposobnosti s profesionalnom bolesti njihovih pacijenata, o potrebi poboljÅ”anja suradnje sa specijalistima medicine rada i potrebi lijeÄnika obiteljske medicine za edukacijom u pojedinim podruÄjima zdravlja na radu i profesionalnih bolesti te temama i naÄinima provedbe edukacije.
Ispitanici su bili lijeÄnici, specijalisti obiteljske medicine i lijeÄnici opÄe medicine koji su zaposleni u ambulantama obiteljske medicine u Zagrebu. Analizirane su prijavljene profesionalne bolesti u ambulantama obiteljske medicine. Od ukupnog broja lijeÄnika obiteljske medicine (N=50), 26 % prijavilo je profesionalnu bolest kod svojih osiguranika, 70 % nije prijavilo, a njih 4 % nisu znali jesu li u posljednjih 5 godina prijavili profesionalnu bolest. U skupini prijavljenih profesionalnih bolesti (N=13) najzastupljenije su bile bolesti miÅ”iÄno-koÅ”tanog sustava (38 %) i kožne bolesti (38 %). NajÄeÅ”Äi razlozi neprijavljivanja bili su nepoznavanje kauzaliteta i sprege s radnim mjestom kod 91 % lijeÄnika, te u 9 % sluÄajeva i strah da Äe pacijent dobiti otkaz.
Velika veÄina ispitanika (94 %) slaže se da je potrebno poboljÅ”ati suradnju izmeÄu obiteljskih lijeÄnika i specijalista medicine rada. Zainteresiranost za edukaciju iskazalo je 78 % obiteljskih lijeÄnika, a potreba postoji za edukacijom iz podruÄja prepoznavanja profesionalnih bolesti. Timskim preventivnim radom specijalista medicine rada i sporta i obiteljskih lijeÄnika, uporabom ācheck listaā u ordinacijama obiteljske medicine i odabranim edukativnim teÄajevima iz podruÄja zdravlja na radu unaprijedila bi se primarna prevencija profesionalnih bolesti, a ranim otkrivanjem sprijeÄila daljnja oÅ”teÄenja zdravlja i smanjila invalidnost koja nastaje kao posljedica obolijevanja od profesionalnih bolesti.The aim of this study is to investigate the views of general practitioners regarding the reporting of occupational diseases and the possible link between work status, sickness and assessment of work ability with occupational diseases. The study also places focus on the need to improve collaboration with occupational medicine specialists, on general practitioners\u27 need for education in certain areas of occupational health and occupational diseases, and on topics and ways of implementing education.
The subjects were family physicians and general practitioners (50) employed in community health centers in Zagreb. The reported occupational diseases in family physician\u27s surgeries were analyzed. It was found that 26% respondents reported occupational disease, 70% did not report it, and 4% did not know whether or not they had reported occupational disease in the last five years. The most commonly reported occupational diseases were diseases of the musculoskeletal system (38%) and skin diseases (38%). The reasons given for not reporting occupational diseases were that doctors were not aware that those were occupational diseases (91%), and because they feared that the patient may get fired (9%).
The vast majority of respondents (94%) agreed that it is necessary to improve cooperation between family physicians and occupational medicine specialists. Seventy eight percent of family physicians were interested in education on how to recognize occupational diseases. Preventive team work on the part of occupational medicine specialists and family physicians using the \u27check lists\u27 in family physician\u27s surgeries, and education courses on occupational health would improve primary prevention of occupational diseases, while early detection would halt the progress of occupational diseases and thus reduce ensuing disability caused by occupational disease
Two-year Rehospitalization Rates of Patients with Newly Diagnosed or Chronic Schizophrenia on Atypical or Typical Antipsychotic Drugs: Retrospective Cohort Study
Cilj Odrediti smanjuju li atipiÄni antipsihotiÄki lijekovi stopu rehospitalizacije bolesnika s novodijagnosticiranom ili kroniÄnom shizofrenijom viÅ”e nego tipiÄni lijekovi.
Postupci Od 1. sijeÄnja 2003. do 31. prosinca 2004. retrospektivno smo usporeÄivali dvogodiÅ”nje stope rehospitalizacije 135 bolesnika s novodijagnosticiranom i 398 bolesnika s kroniÄnom shizofrenijom (62%, odnosno 65% muÅ”karaca) koji su otpuÅ”teni s lijeÄenja u Psihijatrijskoj bolnici VrapÄe u Zagrebu u razdoblju izmeÄu 1. sijeÄnja 2002. do 31. prosinca 2002. a bili su im prepisani atipiÄni (olanzapin, risperidon ili klozapin) ili tipiÄni (haloperidol ili flufenazin) antipsihotici. Vrijeme do ponovnog primanja u bolnicu odreÄeno je Kaplan-Meierovom formulom za analizu preživljenja.
Rezultati Za vrijeme dvije godine koliko je trajalo praÄenje rehospitalizirana su 52 (39%) bolesnika s novodijagnosticiranom i 197 (47%) bolesnika s kroniÄnom shizofrenijom. Nije bilo znaÄajnih razlika u vremenu do rehospitalizacije s obzirom na vrstu uzimanog lijeka izmeÄu bolesnika s novodijagnosticiranom (P=0,378) i bolesnika s kroniÄnom shizofrenijom (P=0,531).
ZakljuÄak. Stopa rehospitalizacije u bolesnika kojima su prepisani atipiÄni antipsihotici bila je sliÄna stopi u bolesnika kojima su prepisani tipiÄni antipsihotici i za bolesnike s novodijagnosticiranom i za bolesnike s kroniÄnom shizofrenijom.Aim To determine if atypical antipsychotic agents reduce the rehospitalization
rates of patients with newly diagnosed or chronic schizophrenia
in comparison with typical antipsychotic drugs.
Methods From January 1, 2003, to December 31, 2004, we retrospectively
compared two-year rehospitalization rates of 135 patients with newly
diagnosed schizophrenia and 398 patients with chronic schizophrenia
(62% and 65% men, respectively), who were initially discharged from
VrapÄe Psychiatric Hospital, Zagreb, with the prescription of atypical
(olanzapine, risperidone or clozapine) or typical (haloperidol or fluphenazine)
antipsychotic treatment between January 1, 2002 and December
31, 2002. Time-to-readmission was determined with Kaplan-Meier formula
for survival analysis.
Results In the two-year follow-up, 52 (39%) newly diagnosed patients
and 197 (47%) patients with chronic schizophrenia were rehospitalized.
No significant differences in time-to-rehospitalization were observed
with respect to the type of medications in patients with newly diagnosed
schizophrenia (P = 0.378) or patients with chronic schizophrenia
(P = 0.531).
Conclusions. Rehospitalization rates of patients who were prescribed
atypical antipsychotic drugs were similar to those of patients who were
prescribed typical antipsychotic drugs for both the group with the first
psychotic episode and group with chronic schizophrenia
Buckweat yields in intercropped systems of walanut and buckwheat
IstraÅ£ivanje prinosa heljde u konsocijacijskom uzgoju provedeno je na dvije lokacije, u Äakovu gdje se nalazi 11 godina star voÄnjak oraha te u Ivankovu na voÄnjaku starosti 4 godine. Na obje lokacije se pokus postavio s kontrolnim poljem heljde, kontrolnim dijelom voÄnjaka i konsocijacijskim dijelom gdje je heljda bila usijana izmeÄu 5 nisko produktivnih redova. Tijekom vegetacije utvrÄen je agrokemijski sastav tla, mjerena je Å”irina kroÅ”nje zbog utvrÄivanja efekta zasjenjivanja te insolacija dok je prilikom Å£etve izraÄunat prinos i utvrÄena brojnost korova te naposlijetku omjer ekvivalentne vrijednosti zemljiÅ”ta(LER). Rezultati su pokazali da je korelacija direktnog sunÄevog zraÄenja u odnosu na sunÄevo zraÄenje u sjeni kroÅ”nje najniÅ£a u ljetnim mjesecima(6-8 %), potom u listopadu (20 %), dok je u travnju(30 %), a najviÅ”a u studenom gdje je kroÅ”nja bez lisne mase(85 %). Rezultati prinosa heljde pokazali su statistiÄki niÅ£e prinose u starijem voÄnjaku u usporedbi s kontrolnim zemljiÅ”tem zbog preklapanja vegetacije s razgranatim orasima Å”to je rezultiralo smanjim urodom za 28 % ali poveÄala se ukupna produktivnost takvog podruÄja(LER=1,05) , dok u 4-godiÅ”njem voÄnjaku oraha nije bilo statistiÄke znaÄajne razlike izmeÄu prinosa heljde u voÄnjaku i na kontrolnoj parceli.Rezultati ukazuju da je moguÄe uzgajati poljoprivredne kulture poput heljde u konsocijaciji s orahom, no takva proizvodnja je isplativa do odreÄene granice, a veÄ provedena istraÅ£ivanja na tu temu pokazuju da prinosi usjeva u konsocijacijaskom sustavu obiÄno drastiÄno opadnu oko 8-10 godina od sadnje Å”to ukazuje da je efekt zasjenjenja pokretaÄka sila koja kontrolira prinose heljde u takvim kombiniranim sustavima.Research on buckwheat yield in intercropped system has been demonstrated at two locations - in Djakovo where the 11-year-old walnut orchard is located and in Ivankovo, on a 4-year-old orchard. In both locations the experiment included a buckwheat control field, control parts of orchards and intercropped plots where buckwheat was sown between 5 low productive rows. During vegetation the agrochemical composition of the soil was determined, the width of the canopy was measured to determine the effect of shading and insolation, while during harvest the yield was measured and the number of weeds was determined, and finally the land equivalent ratio (LER) was calculated. The results showed that the correlation of direct solar radiation with respect to the sun radiation in the shade of the canopy is lowest in the summer (6-8%), then in October (20%), while in April it was 30%, and highest in November because of a leafless canopy (85%). Buckwheat yields statistics showed lower yield in an older orchard compared to control field due to overlapping vegetation with branched nuts, resulting in yield reduction of 28% but increased the overall productivity of such areas (LER = 1.05). The four year old walnut orchard had no statistically significant differences between the buckwheat yield in the orchard and the control field. Results point to the possibility of growing plants like buckwheat in intercropped system with walnut trees, but production of this kind is only profitable to an extent. Previous research on the subject shows that yields in the consociation system typically decline drastically about 8-10 years from planting, indicating that the shading effect is the force controlling the buckwheat yields in such combined systems
The effect of soil chemical and phisical properties on soil plasticity
Na tri razliÄita tipa tla (aluvijalno, lesivirano i ritska crnica) utvrÄen je utjecaj kemijskih i fizikalnih svojstva oraniÄnih horizonata na plastiÄnost tla. Vrlo znaÄajnu korelaciju pozitivnog smjera sa plastiÄnoÅ”Äu pokazali su humus, glina, KIK, sitni prah, magnezij, natrij i kalcij dok su vrlo znaÄajnu korelaciju ali negativnog smjera pokazali hidrolitiÄka kiselost, krupni pijesak, sitni pijesak i krupni prah. StatistiÄkom obradom podataka utvrÄene su statistiÄki znaÄajne razlike izmeÄu svih istraživanih tipova tala i to za glinu, volumnu gustoÄu tla i za gustoÄu pakiranja, te za aktualnu i supstitucijsku kiselost, kationski izmjenjivaÄki kapacitet tla te sadržaj kalcija. TakoÄer, utvrÄene su statistiÄki znaÄajne razlike izmeÄu istraživanih tala za donju granicu plastiÄnosti, za gornju granicu plastiÄnosti i za indeks plastiÄnosti. ProsjeÄna utvrÄena vrijednost donje granice plastiÄnosti kao važnog elementa za odreÄivanje trenutka obrade tla iznosila je 18,90 % na aluvijalnom tlu, 24,06 % na lesiviranom tlu, dok je na ritskoj crnici iznosila 28,6 %.In three different soil types (fluvisol, luvisol and humic gyesol), the influence of chemical and physical properties of the arable horizons on the soil plasticity was determined. Highly significant positive correlation was determined between plasticity and humus, clay, CEC, small dust particles, magnesium, sodium and calcium, while significatly negative correlation was shown was shown for palsticity with hydrolytic acidity, large sand, fine sand and larger dust particles. Statistical data analysis revealed statistically significant differences in clay, soil density and packing density, and for current and substituent acidity, cation exchange capacity of soil and calcium content, between all the examined types of soil. Also, statistically significant differences were found between soils examined for the lower limit of plasticity, the upper plasticity limit and for the plasticity index. The average value of the lower limit of plasticity, as an important element for determining the ideal time for soil tillage, was 18.90% on fluvisol soil, 24.06% on the luvisol soil, while in the humic gyesol soil that value was 28.6%
The effect of soil chemical and phisical properties on soil plasticity
Na tri razliÄita tipa tla (aluvijalno, lesivirano i ritska crnica) utvrÄen je utjecaj kemijskih i fizikalnih svojstva oraniÄnih horizonata na plastiÄnost tla. Vrlo znaÄajnu korelaciju pozitivnog smjera sa plastiÄnoÅ”Äu pokazali su humus, glina, KIK, sitni prah, magnezij, natrij i kalcij dok su vrlo znaÄajnu korelaciju ali negativnog smjera pokazali hidrolitiÄka kiselost, krupni pijesak, sitni pijesak i krupni prah. StatistiÄkom obradom podataka utvrÄene su statistiÄki znaÄajne razlike izmeÄu svih istraživanih tipova tala i to za glinu, volumnu gustoÄu tla i za gustoÄu pakiranja, te za aktualnu i supstitucijsku kiselost, kationski izmjenjivaÄki kapacitet tla te sadržaj kalcija. TakoÄer, utvrÄene su statistiÄki znaÄajne razlike izmeÄu istraživanih tala za donju granicu plastiÄnosti, za gornju granicu plastiÄnosti i za indeks plastiÄnosti. ProsjeÄna utvrÄena vrijednost donje granice plastiÄnosti kao važnog elementa za odreÄivanje trenutka obrade tla iznosila je 18,90 % na aluvijalnom tlu, 24,06 % na lesiviranom tlu, dok je na ritskoj crnici iznosila 28,6 %.In three different soil types (fluvisol, luvisol and humic gyesol), the influence of chemical and physical properties of the arable horizons on the soil plasticity was determined. Highly significant positive correlation was determined between plasticity and humus, clay, CEC, small dust particles, magnesium, sodium and calcium, while significatly negative correlation was shown was shown for palsticity with hydrolytic acidity, large sand, fine sand and larger dust particles. Statistical data analysis revealed statistically significant differences in clay, soil density and packing density, and for current and substituent acidity, cation exchange capacity of soil and calcium content, between all the examined types of soil. Also, statistically significant differences were found between soils examined for the lower limit of plasticity, the upper plasticity limit and for the plasticity index. The average value of the lower limit of plasticity, as an important element for determining the ideal time for soil tillage, was 18.90% on fluvisol soil, 24.06% on the luvisol soil, while in the humic gyesol soil that value was 28.6%