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Soil sampling is the first step in generating field-specific information on which to base agricultural input decisions. The objective of the study was to evaluate spatial and temporal variability of soil pH, plant available phosphorus (P2O5) and potassium (K2O) content under variable mineral nitrogen (N) fertilization. The research was conducted on the experimental field within hydro-ameliorated cropland in the Western Pannonia subregion of Croatia (45°33’N, 16°31’E). Grid soil sampling (15x15 m ; n=200) was carried out with semi-automatic circular tractor soil probe at 30 cm depth after winter wheat harvest in 2010 and 2016 covering ten fertilization treatments (0-300 kg N ha-1). A sequence of spatial changes in soil properties was influenced by differences in N rates, liming, field drainage and specific terrain features, although similar spatial response was apparent for both investigated years. A two-way ANOVA revealed that only soil pH values significantly differed among two years (p

Nowadays, when the negative impact of nitrogen fertilization is recognized, requisites are arising to determine the actual contribution of specific agricultural practices on environment degradation. Isotope analyses are imposing as key techniques for confirmation of nitrogen origin in soil and agricultural impact on ecological footprint of nitrogen on environment. Main objectives of this research were: (a) to determine soil δ15N isotope content regarding the variable doses of nitrogen fertilization and soil depth ; (b) to determine δ15N isotopic signature in applied commercial nitrogen fertilizers. Research was based on 12 soil samples and 9 fertilizers [urea, granular and piled LAN (limestone ammonium nitrate) and six NPK fertilizer formulations]. Soil samples were collected from a stationary field experiment in 2018 located in central part of Croatia after 22 years of application variable nitrogen doses (0, 100, 200 and 300 kg N/ha) on three depths (0-30, 30-50 and 50-80 cm). Analyses were performed in 2021 in two replications and δ15N isotopes in soil and fertilizers were determined by the EA-IRMS method. The results reveal that variability of the δ15N isotope content in soil (+5.1 ‰ to +7.7 ‰) indicates the organic origin of nitrogen in the soil despite the long-term application of mineral nitrogen fertilizers. As a confirmation of this allegation the range of δ15N values in the applied nitrogen fertilizers was from -0.96 ‰ in piled LAN up to +3.26 ‰ in NPK 7-20-30, implying that observed fertilizers were produced by processes of "industrial" fixation of atmospheric nitrogen and they did not leave a mark on the total nitrogen in the soil.

Recent global warming and more frequent droughts are causing significant damage to maize production. A reliable estimate of drought intensity and duration is essential for testing maize hybrids to drought tolerance. For this purpose, the self-calibrating 10-day Palmer drought severity index (scPDSI) and standardized precipitation index (SPI) for 1, 2, 3, 6, 9, 18, 27, and 36 10-day scales were used to estimate the effects of drought on grain yield of 32 maize hybrids evaluated in 2017 and 2018 at eight experimental locations in the Pannonian part of Croatia. Time series of observed 10-day mean air temperature, relative humidity, and precipitation totals for a set of “reference” weather stations of the Croatian Meteorological and Hydrological Service (DHMZ) for the period 1981–2018 were used to calculate the scPDSI and SPI indices. According to the 10-day scPDSI and SPI for different time scales, 2018 proved to be a “normal year, ” while 2017 experienced a “mild to moderate drought, ” which resulted in a 13% reduction in maize grain yield at eight experimental locations compared to 2018. The correlation between grain yield and drought indices for summer months was the highest for the 10-day scPDSI. To some extent, correlations between summer months’ SPI for the 3 10-day time scale and maize grain yield were comparable to the corresponding correlations for the 10-day sc PDSI. However, for otherSPI time scales considered, the corresponding correlations were weaker and less informative. The dependence of grain yield on sc PDSI values was not the same for all hybrids, indicating their different tolerance to drought. The reduction in grain yield due to drought was primarily caused by insufficient grain filling (lower 1000-grain weight) and, to some extent, by a reduction in the number of grains. In this study, application of 10-day sc PDSI data proved to be more relevant in detecting effects of drought on agronomic traits than application of SPI data for the most time scales.

The need to reduce the environmental impact of agricultural activities and to control soil structure degradation is one of the main aims of conservation land management. We show here the experiments and measurements we conduct within the SEDCRO project to help the scientists, farmers and policy makers in the understanding of the soil and hydrologic processes. The main factors that determine soil losses and runoff was assessed: slope, soil management, vegetation cover, organic matter, infiltration, soil moisture, soil water repellency, and structural stability. Project outcome reveal that several strategies should have to been developed to reduce the most important degradation problem - soil erosion: 1) terracing on steep slopes, 2) use of cover crops, 3) mulching and 4) no-tillage. Inappropriate practices (wheeling, agrochemicals, tillage) accelerates soil compaction, runoff and soil erosion in Croatian pedosphere. This also increase risk of surface water pollution. Complex of agricultural, social, economic and environmental reasons are generally the driving force for unsustainable soil management practices in Croatian agricultural land. SEDCRO project fill the gaps in several missing things: 1) a lack of research of proportion of soil erosion in Croatia ; 2) lack of knowledge of driving forces of erosion - like aggregate stability, effect of slope, and physical and chemical properties which control the aggregate breakdown ; in contrast to: a) different soil types b) land use, c) topography and d) rainfall intensity. The mechanisms, processes, rates and control of soil erosion have been scientifically studied for more than four years to convey new findings and discuss new challenges. In Croatia, such research trough SEDRCO project provides more than 19 scientific papers, 1 book and 1 book chapter, while from 3 PhD candidates that work on project one become doctor and other two will be in 2023. Outcome of the SEDCRO project will help to improve management of agricultural soils under more pronounced every-day climatic extremes in Croatian environment. Research of soil erosion and degradation on Croatian provide deep insight for understanding the processes of soil degradation and extent of degradation damage for future change of legal policy. Present subject of research helps to discover most endanger soils and unsustainable land use practices, which help to conserve soil and water for future generations.

Recent global warming and more frequent droughts are causing significant damage to maize production. A reliable estimate of drought intensity and duration is essential for testing maize hybrids to drought tolerance. For this purpose, the self-calibrating 10-day Palmer drought severity index (scPDSI) and standardized precipitation index (SPI) for 1, 2, 3, 6, 9, 18, 27, and 36 10-day scales were used to estimate the effects of drought on grain yield of 32 maize hybrids evaluated in 2017 and 2018 at eight experimental locations in the Pannonian part of Croatia. Time series of observed 10-day mean air temperature, relative humidity, and precipitation totals for a set of “reference” weather stations of the Croatian Meteorological and Hydrological Service (DHMZ) for the period 1981–2018 were used to calculate the scPDSI and SPI indices. According to the 10-day scPDSI and SPI for different time scales, 2018 proved to be a “normal year, ” while 2017 experienced a “mild to moderate drought, ” which resulted in a 13% reduction in maize grain yield at eight experimental locations compared to 2018. The correlation between grain yield and drought indices for summer months was the highest for the 10-day scPDSI. To some extent, correlations between summer months’ SPI for the 3 10-day time scale and maize grain yield were comparable to the corresponding correlations for the 10-day sc PDSI. However, for otherSPI time scales considered, the corresponding correlations were weaker and less informative. The dependence of grain yield on sc PDSI values was not the same for all hybrids, indicating their different tolerance to drought. The reduction in grain yield due to drought was primarily caused by insufficient grain filling (lower 1000-grain weight) and, to some extent, by a reduction in the number of grains. In this study, application of 10-day sc PDSI data proved to be more relevant in detecting effects of drought on agronomic traits than application of SPI data for the most time scales.

Požari su dio prirodne dinamike mediteranskog ekosustava te mogu uzrokovati trajne promjene i degradaciju tala. Glavna svrha istraživanja bila je primijeniti spektralne podatke dobivene iz satelitskih snimaka za praćenje utjecaja požara na sadržaj organske tvari (OT) tla. Istraživanje je provedeno u Zadarskoj županiji na približno 13.5 ha požarom zahvaćene šume Quercus pubescens Willd. i Juniperus communis L. Ukupno 120 uzoraka tla (0-5 cm dubine) prikupljeno je dva dana nakon požara. Dvije satelitske snimke sa Sentinel-2 satelita preuzete su s čvorišta otvorenog pristupa Europske svemirske agencije (ESA) prema najbližim datumima terenskog uzorkovanja, a svaka sadrži osam vidljivo-blisko infracrvena (VIS-NIR) i dva kratkovalna infracrvena (SWIR) pojasa koji su izdvojeni iz piksela tla. Za procjenu sadržaja OT iz spektralnih podataka uspoređeni su linearni model parcijalne regresije najmanjih kvadrata (PLSR) i nelinearni model umjetnih neuronskih mreža (ANN). Točnost modela određena je pomoću korijena prosječne kvadratne pogreške predviđanja (RMSEp) i omjera performansi i odstupanja (RPD). Oba modela pokazala su niske RMSEp i visoke RPD vrijednosti koje ukazuju na vrlo dobra predviđanja sadržaja OT tla. Daljinska istraživanja pokazala su velik potencijal u analizi i praćenju OT tla u post-požarnom razdoblju.

Wildfires have provided regulatory services in many terrestrial ecosystems throughout history. Low severity fires promote rapid vegetation recovery, and generally have a neutral impact on most soil properties, while high severity fires have adverse effects on many soil properties that can cause permanent environmental degradation. The objective of this study was to determine the effect of wildfire severity (HS-high severity ; MS-medium severity ; C-unburned), vegetation type (Q- Quercus p. and J-Juniperus c.) and time-since-fire (3 days, 3, 6, 12, 18 and 24 months) on soil texture in calcocambisol. Soil sampling (0-5 cm, N=180) was carried out on 15 ha of fire affected mixed Quercus pubescens Willd. and Juniperus communis L. forest in Zadar County (Croatia). Soil texture was determined via the pipette-method as silty loam. The results showed that fire severity and vegetation type had significant impact on soil sand, silt, and clay fractions, while their variability over time was not significant (p

Knowledge of nitrogen fertilization contribution to the soil organic carbon (SOC) variability is very important in order to preserve the climate-regulating role of soil through measures of sustainable soil management. The aim of this research was to determine SOC distribution up to 2 meters in drained distric Stagnosol according to different nitrogen fertilization levels. SOC content was determined in 128 soil samples which were sampled from experimental plot (central Croatia, Potok location) after 10 years of fertilization (0, 100, 200, 300 kg N/ha/per year) on eight depths (each 25 cm up to 2 m) in four replications. SOC was determined indirectly by calculation from total soil carbon and carbonate content. Results reveal that long term application of 200 and 300 kg N/ha significantly contribute to SOC enrich especially in surface soil layer. Along with those findings, SOC content was significantly reduced through soil profile on all treatments. The largest SOC stock (615 t/ha) was determined on treatment with 200 kg N/ha applied

Wildfires are a common occurrence in the Mediterranean and geostatistical methods offer the opportunity to effectively monitor their impacts on various soil properties. The goal of this study was to compare Inverse distance weighting with the power of one and two, Ordinary kriging and Empirical Bayesian kriging to determine the most accurate interpolation method for mapping the soil pH, electrical conductivity and organic matter content after a wildfire in Mediterranean Croatia. The results suggested that Ordinary kriging would be the optimal choice for soil pH, while Empirical Bayesian kriging proved more accurate for soil electrical conductivity and organic matter content.

U svrhu praćenja kvalitete i kvantitete biomase miskantusa (Miscanthus x giganteus-MxG), mogu se primijeniti daljinska istraživanja kao nedestruktivna metoda u okviru precizne poljoprivrede. Cilj rada bio je proksimalnom spektroskopijom u vidljivom i blisko infracrvenom (VNIR) području elektromagnetskog spektra utvrditi sadržaj dušika (N) u listu i prinos nadzemne biomase miskantusa u stakleničkom pokusu na tlu onečišćenom kadmijem i živom ovisno o tretmanima različitih poboljšivača tla. Mjerenje refleksije lista prijenosnim spektroradiometrom (350-1050 nm) provedeno je krajem vegetacijskog ciklusa 2018. i 2019. godine (n=24). Sadržaj ukupnog N u listu određen je metodom suhog spaljivanja (HRN ISO 13878:2004), a prinos nadzemne biomase vaganjem neposredno nakon žetve. Parcijalnom regresijom najmanjih kvadrata (PLSR) utvrđena je potpuna korelacija i niska srednja kvadratna pogreška (RMSE) između predviđenih i referentnih vrijednosti za validacijski model ukupnog N u listu (R2=0.87, RMSE=0.139 %), te jaka korelacija (R2=0.53, RMSE=0.833 t/ha) za prinos nadzemne biomase. Proksimalnom spektroskopijom kao dodatnim alatom analitičkim metodama moguće je integrirati optička i fiziološka svojstva biljnog tkiva MxG te utvrditi stres u biljci uzgajanoj na tlima onečišćenim teškim metalima, a koji utječe na koncentraciju biljnih pigmenata, staničnu strukturu lista te neposredno na sadržaj dušika. Za daljinsku procjenu kvantitete biomase uzorak mora biti dio šireg prostornog okvira.

Mnogobrojna istraživanja ukazuju da dugotrajna primjena fungicida na bazi bakra uzrokuje onečišćenje poljoprivrednih tala navedenim metalom. Cilj ovog rada bio je utvrditi utjecaj nagiba padine i različitog načina korištenja tla na prostornu akumulaciju bakra u poljoprivrednim tlima. Istraživanje je provedeno u listopadu 2019. godine u sjeverozapadnoj Hrvatskoj na površini smještenoj na padini koja obuhvaća: dva vinograda (zatravljeni i nezatravljeni), oranicu i livadu. U površinskim (0-10 cm) prosječnim uzorcima tla nakon digestije zlatotopkom sadržaj bakra utvrđen je primjenom atomske apsorpcijske spektrometrije (AAS metodom). Provedena istraživanja ukazuju da je nagib padine pridonio varijabilnosti bakra u tlu, koja se značajno smanjivala od vrha padine gdje su smješteni vinogradi do podnožja na kojem se nalazi oranica i livada. Rezultati dodatno potvrđuju i na djelovanja erozije vodom koja je imala utjecaj na sadržaj bakra u tlu oranice prostorno smještene na padini ispod vinograda. Uvažavajući propisanu nacionalnu legislativu (MDK 120 mg kg-1 ; NN 71/2019) može se zaključiti da je u tlu oba vinograda zabilježen nedozvoljeni sadržaj bakra (135-272 mg/kg), te da je u nastavku padine u tlu oranice i livade utvrđen prihvatljiv sadržaj bakra (40, 1-82, 0 mg/kg). Dodatno, značajno viši sadržaj bakra u tlu zatravljenog vinograda (245 mg/kg) u odnosu na nezatravljeni vinograd (140 mg/kg) djelomično je uzrokovan višim sadržajem organske tvari u zatravljenom vinogradu.

U elemente platinske skupine (eng. platinum group of elements- PGE) spadaju platina (Pt), paladij (Pd) i rodij (Rh). Upotreba tih elemenata danas u svijetu je velika i široka, od elektronike preko stomatologije, draguljarstva i medicine, sve do automobilske industrije. Automobilski katalizatori imaju važnu ulogu u radu ispušnih sustava, smanjujući emisije plinovitih onečišćujućih tvari. Međutim, vrući ispušni plinovi koji prolaze kroz automobilski katalizator uzrokuju emisije PGE u okoliš i mogu predstavljati potencijalni rizik za zdravlje ljudi jer su alergeni. Do ovog istraživanja na Institutu za medicinska istraživanja i medicinu rada (IMI) razrađena je metoda za određivanje koncentracija PGE u lebdećim česticama u zraku, međutim ne i u biljci i tlu. Za sada u našoj zemlji ne postoje podaci o razinama navedenih metala u drugim sastavnicama okoliša (vegetacija i tlo) osim u zraku. Ciljevi ovog istraživanja bili su: (i) razraditi i prilagoditi metodu za određivanje PGE u biljci i tlu ; (ii) u blizini lokacija (3 u Zagrebu) na kojima se već sakupljaju uzorci lebdećih čestica u zraku prikupiti uzorke ostalih sastavnica okoliša (tla i biljke) te odrediti koncentracije PGE u njima ; (iii) utvrditi sezonske (proljeće i jesen) i prostorne (3 urbane lokacije) razlike u koncentracijama PGE u pojedinim sastavnicama okoliša, te utvrditi povezanost između njih (tlo, biljka, zrak). Uzorci tla i vegetacije sakupljani su na tri lokacije u različito onečišćenim dijelovima grada Zagreba. Uzorci vegetacije i tla sakupljani su tijekom dvije godine (2018.-2019.) dva puta godišnje (u proljeće i jesen) ; po dva uzorka biljnog materijala (Plantago Lanceolata L. i Dactylis glomerata L.) i po dva uzorka tla (2 dubine: 0-5 cm i 5- 10 cm) sa svake lokacije. Tjedni uzorci lebdećih čestica aerodinamičkog promjera manjeg od 10 µm (frakcija PM10 ) sakupljani su tijekom cijele godine. Priprava i analiza uzoraka na PGE provodila se po metodi koja se razradila u sklopu ovog istraživanja, a sastojala se od priprave uzoraka razgradnjom u kiselini uz mikrovalove pri povišenoj temperaturi i tlaku te analize spektrometrijom masa uz induktivno spregnutu plazmu (ICP-MS). Tlo se analiziralo i na osnovne agrokemijske analize bitne za razumijevanje mobilnosti i biodostupnosti PGE (tekstura, pH, EC, OT, (P i K)AL, CEC, zamjenjivi Na+, K+, Ca2+ i Mg2+, vodotopivi anioni i kationi, CaCO3, TN, TS, te elementarni sastav od Mg do U). Rezultati pokazuju značajno veće koncentracije Pd u tlu, zraku i vegetaciji od Rh i Pt. Plantago Lanceolata L. pokazuje veći sadržaj PGE od Dactylis glomerata L. Koncentracije u tlu i zraku kreću se u nizu Pt > Rh > Pd, a u biljnom materijalu Rh > Pt > Pd.

Wildfire impacts on soil chemical properties can be detected through spectral signature. Fire severity effects on soil can be assessed using proximal spectroscopy. This method is non-destructive and estimates several soil properties. The objective of this work is to 1) estimate and monitor the effects of wildfire on 11 soil chemical properties using visible and near infrared (VNIR) hyperspectral reflectance and 2) compare model performance obtained by linear calibration methods and data mining techniques. The study was carried out in the Šibenik-Knin County (Croatia) following a summer wildfire that affected an area of 6 ha. A total of 120 topsoil (0 to 3 cm depth) (10 replicates x 3 treatments x 4 time periods) samples from were collected in the interval of 5 days, 3 months, 6 months and 1 year after the wildfire. Samples were collected in plots affected by medium (MS), high severity (HS) and from a non-burned area (control – C). The following soil properties were determined using standard laboratory methods: soil pH, electrical conductivity (EC), carbonates (CaCO3), plant available phosphorus (P2O5) and potassium (K2O), organic carbon (OC), exchangeable calcium (Ca), magnesium (Mg), potassium (K), sodium (Na) and cation exchange capacity (CEC). Soil spectral measurements were obtained using a portable spectroradiometer. Partial least square regression (PLSR) and artificial neural network (ANN) were used to build prediction models of selected soil properties based on original soil reflectance data and first derivative of reflectance. PLSR model was calibrated using cross validation method. In ANN regression analysis, spectra were randomly divided into training and testing sets with proportions of 50% and 50%, respectively. The results showed that spectral reflectance differed (p

Sveučilište u Zagrebu Agronomski fakultet obvezao se izraditi elaborat naslova: „Osnovne postavke projektnog prijedloga za potrebe uspostave sustava izmjere promjene zalihe ugljika u biomasi (fitotvari) u kategorijama zemljišta usjeva/nasada i travnjaka LULUCF-a“. Polazište za izradu ovog elaborata su zahtjevi stručnog revizijskog tima UNFCCC-a prema RH da unaprijedi razinu izvješćivanja u LULUCF sektoru odnosno da prijeđe na više razine IPCC metodologije (Tier 2 ili Tier 3) prilikom izrade izvješća o emisijama staklenih plinova iz LULUCF sektora. Svojim sadržajem elaborat predstavlja stručnu podlogu tom cilju, odnosno stvaranju osnovnih postavki projektnog prijedloga za potrebe uspostave sustava izmjere promjene zalihe ugljika u biomasi (fitotvari) u kategorijama zemljišta usjeva/nasada i travnjaka LULUCF-a.