Crystallographic Determination of Titanite from Smilevski Dol in Selečka Mountain, Macedonia

On 30 crystal s of titani tc, goniometrically measured, the appearance of faces of 25 forms was determined. Crystallographic elements were calculated and morphology and paragenesis of minerals were described.The shape of the crystals was represented by ten parallel perspective figures. Two types of crystal s were separated

POTASSIUM DYNAMICS AND COMPARISON OF METHODS FOR DETERMINATION OF AVAILABLE POTASSIUM IN SOILS OF EASTERN CROATIA

Kalij pripada alkalnoj grupi elemenata, sedmi je najrasprostranjeniji element u Zemljinoj kori te jedan od elemenata koji ulaze u sastav minerala koji tvore matične stijene iz kojih se procesima pedogeneze razvijaju tla. Kalij se nalazi u većini tala u relativno velikim količinama, premda može varirati u širokom rasponu ovisno o teksturi tla. Provedeno istraživanje usmjereno je na problematiku statusa kalija u različitim poljoprivrednim tlima Istočne Hrvatske, te je cilj istraživanja bio usporediti metode ekstrakcije lako pristupačnog kalija iz tla s AL-metodom kao najraširenijom metodom u Republici Hrvatskoj, odrediti utjecaj tipa tla na pogodnost metode za analizu lako pristupačnog kalija u tlu, odrediti utjecaj tipa tla i fizikalno-kemijskih svojstava na fiksaciju kalija te izraditi kompjutorski model procjene fiksacije kalija u različitim tlima. Uzorci su obuhvaćali devet sistematskih jedinica unutar sedam tipova tala: eutrično smeđe tlo, lesivirano tlo, lesivirano preudoglejno, pseudoglej, aluvij, pseudoglej glej, ritsku crnicu, močvarno glejno hipoglejno te močvarno glejno amfiglejno tlo. Fizikalna svojstva tla utvrđena su za sve uzorke i za sve tipove tala s izraženom heterogenošću rezulatata gdje je utvrđena statistički značajna razlika između svih tipova tala za sva istraživana svojstva. Svi tipovi tala statistički se značajno razlikuju u dinamici kalija, a značajno najviša frakcija kod svih tipova tala bila je ukupni kalij, zatim slijedi frakcija kalija uklopljenog u kristalnu rešetku minerala, frakcija teško pristupačnog kalija te na kraju frakcija lako pristupačnog kalija. Usporedba analiziranih kemijskih metoda ekstrakcije kalija iz tla visoke je preciznosti, a najpouzdanije su usporedbe AL metode s AAEDTA, zatim slijedi redom: AA, BaCl2, EUF, Bray, EUF1 i EUF 2 metoda. Regresijski modeli vrlo su jednostavni i primjenjivi jer mogu dati nove podatke već na temelju koncentracije kalija ekstrahiranog AL metodom. Preciznost modela značajno povećavaju podatci o ostalim agrokemijskim svojstvima tla, prije svih pH reakcija, te sadržaj humusa. Dopunski preciznost modela mogu povećati rjeđe raspoloživi podatci o fizikalnim svojstvima tla, veličini KIK-a i udjelu kalija na KIK-u. Razvijene modele potrebno je validirati setovima podataka poznatih analitički utvrđenih vrijednosti s poljskih pokusaPotassium belongs to the group of alkaline elements, it is the seventh most abundant element in the Earth's crust, and one of the elements that enter into the composition of minerals that form the parent rocks from which the soils are formed. Potassium is found in most soils in relatively large quantities, although its concentrations may vary based on the soil texture. The research is focused on the problem of the status of potassium in different agricultural soils of Eastern Croatian, and the aim of the study was to compare the extraction methods of readily available potassium in the soil with AL-method as the most common method in the Republic of Croatia, to determine the influence of soil type on the suitability of methods for the analysis of easily accessible potassium in the soil, to determine the effects of soil type and physico-chemical properties on the fixation of potassium, and to create a computer model that estimates fixation of potassium in different soils. Exchangeable acidity (pH KCl) of investigated soils ranged from 3.27 to 7.91, organic matter content ranged from 0.83 to 11.80%, AL-P ranged from 0.58 to 171.88mg/100g , AL-K from 6.88 to 63,35 mg 100g, Hy 0.22 to 8.40, and carbonate content from 0.84 to 16.13%, which means that the samples were very heterogeneous. All soil types have statistically significant difference in the dynamics of potassium, where substantially highest fraction at all soil types was total potassium fraction, followed by potassium fraction that is incorporated in the crystal structure, fraction of low available potassium, and finally fraction of the readily available potassium. Comparison of analyzed extraction methods of potassium from the soil is of high precision, and most reliable comparisons are of AL methods with AAEDTA, followed by a: AA, BaCl2, ECF, Bray, EUF1 and ECF 2 method. Regression models are very simple and applicable since they can provide new information based on the concentration of potassium extracted AL method. The accuracy of the model significantly increases by using additional soil properties data, mainly the pH reaction and organic matter content. Additional precision of the model can increase by adding some additional soil properties data such as CEC and proportion of potassium in CEC. The developed model is necessary to be validated on the data sets of known analytically determined values from field experiments

POTASSIUM DYNAMICS AND COMPARISON OF METHODS FOR DETERMINATION OF AVAILABLE POTASSIUM IN SOILS OF EASTERN CROATIA

Kalij pripada alkalnoj grupi elemenata, sedmi je najrasprostranjeniji element u Zemljinoj kori te jedan od elemenata koji ulaze u sastav minerala koji tvore matične stijene iz kojih se procesima pedogeneze razvijaju tla. Kalij se nalazi u većini tala u relativno velikim količinama, premda može varirati u širokom rasponu ovisno o teksturi tla. Provedeno istraživanje usmjereno je na problematiku statusa kalija u različitim poljoprivrednim tlima Istočne Hrvatske, te je cilj istraživanja bio usporediti metode ekstrakcije lako pristupačnog kalija iz tla s AL-metodom kao najraširenijom metodom u Republici Hrvatskoj, odrediti utjecaj tipa tla na pogodnost metode za analizu lako pristupačnog kalija u tlu, odrediti utjecaj tipa tla i fizikalno-kemijskih svojstava na fiksaciju kalija te izraditi kompjutorski model procjene fiksacije kalija u različitim tlima. Uzorci su obuhvaćali devet sistematskih jedinica unutar sedam tipova tala: eutrično smeđe tlo, lesivirano tlo, lesivirano preudoglejno, pseudoglej, aluvij, pseudoglej glej, ritsku crnicu, močvarno glejno hipoglejno te močvarno glejno amfiglejno tlo. Fizikalna svojstva tla utvrđena su za sve uzorke i za sve tipove tala s izraženom heterogenošću rezulatata gdje je utvrđena statistički značajna razlika između svih tipova tala za sva istraživana svojstva. Svi tipovi tala statistički se značajno razlikuju u dinamici kalija, a značajno najviša frakcija kod svih tipova tala bila je ukupni kalij, zatim slijedi frakcija kalija uklopljenog u kristalnu rešetku minerala, frakcija teško pristupačnog kalija te na kraju frakcija lako pristupačnog kalija. Usporedba analiziranih kemijskih metoda ekstrakcije kalija iz tla visoke je preciznosti, a najpouzdanije su usporedbe AL metode s AAEDTA, zatim slijedi redom: AA, BaCl2, EUF, Bray, EUF1 i EUF 2 metoda. Regresijski modeli vrlo su jednostavni i primjenjivi jer mogu dati nove podatke već na temelju koncentracije kalija ekstrahiranog AL metodom. Preciznost modela značajno povećavaju podatci o ostalim agrokemijskim svojstvima tla, prije svih pH reakcija, te sadržaj humusa. Dopunski preciznost modela mogu povećati rjeđe raspoloživi podatci o fizikalnim svojstvima tla, veličini KIK-a i udjelu kalija na KIK-u. Razvijene modele potrebno je validirati setovima podataka poznatih analitički utvrđenih vrijednosti s poljskih pokusaPotassium belongs to the group of alkaline elements, it is the seventh most abundant element in the Earth's crust, and one of the elements that enter into the composition of minerals that form the parent rocks from which the soils are formed. Potassium is found in most soils in relatively large quantities, although its concentrations may vary based on the soil texture. The research is focused on the problem of the status of potassium in different agricultural soils of Eastern Croatian, and the aim of the study was to compare the extraction methods of readily available potassium in the soil with AL-method as the most common method in the Republic of Croatia, to determine the influence of soil type on the suitability of methods for the analysis of easily accessible potassium in the soil, to determine the effects of soil type and physico-chemical properties on the fixation of potassium, and to create a computer model that estimates fixation of potassium in different soils. Exchangeable acidity (pH KCl) of investigated soils ranged from 3.27 to 7.91, organic matter content ranged from 0.83 to 11.80%, AL-P ranged from 0.58 to 171.88mg/100g , AL-K from 6.88 to 63,35 mg 100g, Hy 0.22 to 8.40, and carbonate content from 0.84 to 16.13%, which means that the samples were very heterogeneous. All soil types have statistically significant difference in the dynamics of potassium, where substantially highest fraction at all soil types was total potassium fraction, followed by potassium fraction that is incorporated in the crystal structure, fraction of low available potassium, and finally fraction of the readily available potassium. Comparison of analyzed extraction methods of potassium from the soil is of high precision, and most reliable comparisons are of AL methods with AAEDTA, followed by a: AA, BaCl2, ECF, Bray, EUF1 and ECF 2 method. Regression models are very simple and applicable since they can provide new information based on the concentration of potassium extracted AL method. The accuracy of the model significantly increases by using additional soil properties data, mainly the pH reaction and organic matter content. Additional precision of the model can increase by adding some additional soil properties data such as CEC and proportion of potassium in CEC. The developed model is necessary to be validated on the data sets of known analytically determined values from field experiments

Morfologija kristala i rentgenografske osobitosti brazilijanita s različitih lokaliteta

Forty four brazilianite crystals from several localities in Brazil, Rwanda and Canada were measured on a two-circle goniometer to determine brazilianite morphology. Twenty forms were recorded; six of them have not been recorded before. All faces in the [001] zone are striated along crystallographic axis c. All striated forms in the [001] zone exhibit multiple signals. Two of the signals observed on the form {110} are always very clear. There is an exception on one crystal where just one face, (110), exhibits only one clear signal. Five groups of habits were recorded, two of them new to this mineral species. Eleven samples were examined by X-ray diffraction for calculation of the unit cell parameters yielding a=11.201(1)–11.255(2) Å, b=10.1415(5)–10.155(1) Å, c=7.0885(7)–7.119(2) Å and b=97.431(7)–97.34(1) °. All X-ray diffraction patterns show a peculiarity: some diffraction lines are widened or doubled with the appearance of additional diffraction lines systematically on lower °2Q. These diffraction lines have smaller intensities and cannot be indexed in accordance with brazilianite crystal structure.Četrdeset i četiri kristala brazilijanita s nekoliko lokaliteta iz Brazila, Ruande i Kanade je mjereno na dvokružnom refleksnom goniometru u svrhu određivanja morfologije. Zabilježeno je 20 formi, od kojih šest do sada nije opisano. Sve plohe u zoni [001] su prutane paralelno kristalografskoj osi c. Sve prutane forme u [001] zoni daju višestruke signale. Forma {110} daje višestruke signale od kojih su dva uvijek oštra. Postoji iznimka gdje na jednom kristalu samo jedna ploha, (110), daje samo jedan oštar signal. Zabilježeno je pet grupa habitusa od kojih dva nova za ovu mineralnu vrstu. Jedanaest uzoraka je snimljeno rentgenskom difrakcijom da bi se izračunali parametri jedinične ćelije: a=11.201(1)-11.255(2) Å, b=10.1415(5)-10.155(1) Å, c=7.0885(7)-7.119(2) Å i b=97.431(7)-97.34(1)°. Svi rentgenogrami pokazuju zanimljivost: neke difrakcijske linije su proširene ili podvostručene s pojavom dodatnih difrakcijskih linija sustavno na nižim °2Q. Ove difrakcijske linije su manjeg intenziteta te se ne mogu indicirati u skladu s kristalnom strukturom brazilijanita