7 results on '"Kovač, Zoran"'
Search Results
2. Investigating Near-Surface Hydrologic Connectivity in a Grass-Covered Inter-Row Area of a Hillslope Vineyard Using Field Monitoring and Numerical Simulations.
- Author
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Krevh, Vedran, Filipović, Lana, Defterdarović, Jasmina, Bogunović, Igor, Zhang, Yonggen, Kovač, Zoran, Barton, Andrew, and Filipović, Vilim
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LEAF area index ,HYDRAULIC conductivity ,COMPUTER simulation ,VINEYARDS ,RAINFALL ,MILLENNIALS - Abstract
The interplay of surface and shallow subsurface fluxes plays a critical role in controlling water movement in hillslope agroecosystems and impacting soil and plant health during prolonged dry periods, demonstrating a need for in-field monitoring. This study was conducted for two years (2021–2022) by combining field monitoring of the grass-covered inter-row area (passive wick lysimeter, surface runoff, and meteorological data), laboratory determination of soil hydraulic properties (SHPs), and numerical modeling with the aim to explore near-surface fluxes at the SUPREHILL Critical Zone Observatory (CZO) located on a hillslope vineyard. Additionally, sensitivity analysis for basic root water uptake (RWU) parameters was conducted. The model was evaluated (R
2 , RMSE, and NSE) with lysimeter (hillslope) and runoff (footslope) data, producing good agreement, but only after the inverse optimization of laboratory estimated hydraulic conductivity was conducted, demonstrating that adequate parameterization is required to capture the hydropedological response of erosion-affected soil systems. Results exhibit the dependence of runoff generation on hydraulic conductivity, rainfall, and soil moisture conditions. The data suggest different soil-rewetting scenarios based on temporal rainfall variability. Sensitivity analysis demonstrated that Leaf Area Index (LAI) was the most responsive parameter determining the RWU. The study offers an approach for the investigation of fluxes in the topsoil for similar sites and/or crops (and covers), presenting the methodology of self-constructed soil–water collection instruments. [ABSTRACT FROM AUTHOR]- Published
- 2023
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3. Total concentration and spatial distribution of metals in sloped vineyard soil at the SUPREHILL observatory
- Author
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Han, Luka, Krevh, Vedran, Defterdarović, Jasmina, Filipović, Vilim, Kovač, Zoran, Jakuš Šubašić, Sara, and Filipović, Lana
- Subjects
metal pollution ,hillslope ,agrochemicals ,vadose zone ,metal spatial distribution - Abstract
Frequent use of agrochemicals results in increased concentration of certain metals in vineyard soils, with the slope of terrain promoting their uneven spatial distribution. Therefore, at the SUPREHILL critical zone observatory (Jazbina experimental station, Zagreb), 27 vineyard soil samples were taken at three soil depths (0-30, 30-60, 60-90 cm) in October of 2020 at the top, middle, and the bottom of the slope, and digested in Aqua regia by microwave technique using MARSXpress system, CEM (HRN ISO 11466:2004). Metal (Fe, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, and Hg) total concentrations in soil extracts were then measured using ICP-OES (Vista MPX AX, Varian ; HRN ISO 22036:2011). Data processing was done using Statistical Analysis Software (SAS Institute Inc., Version 8.3 Update 1, Cary NC USA, 2019-2020), with the analysis of variance done using One-Way ANOVA, and the significance of differences between the means determined using Tukey's test at P
- Published
- 2022
4. High-resolution Weighing Lysimeter Measurement Implementation on a Hillslope Vineyard: First Results
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Krevh, Vedran, Mustać, Ivan, Bogunović, Igor, Kovač, Zoran, Filipović, Lana, Defterdarović, Jasmina, Han, Luka, and Filipović, Vilim
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vadose zone ,precipitation ,evapotranspiration ,soil-water potential ,hillslope - Abstract
In late 2020, the first weighing lysimeters in Croatia were installed at the SUPREHILL vadose zone observatory, at the top and bottom of the hillslope. The use of undisturbed weighable lysimeters is commonly used to measure water and solute fluxes at the profile scale, which can also be representative at the field scale. The lysimeters are monolithically filled, equipped with a pressure-controlled lower boundary in order to mimic field dynamics (upward and downward fluxes), and are weighable so that high-precision calculations of hydraulic fluxes (i.e. rainfall, drainage, evapotranspiration, or dew) are possible. The first glance at the 2021 data shows differences between the top and bottom of the hillslope in observed evapotranspiration, while lesser differences are observed in measured precipitation using the system. As a result of the position on the hillslope, different behavior of the soil-water potential that serves as a reference value for establishing equilibrium between the field and lysimeters is observed. Along with the first data from the observatory, the presented material includes installation methodology, system specifications, and description of the feedback control of the lower hydraulic boundary condition with its main components.
- Published
- 2022
5. Identification and quantification of arable hillslope transport processes e.g., preferential flow using soil column study
- Author
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Defterdarović, Jasmina, Krevh, Vedran, Filipović, Lana, Kovač, Zoran, and Filipović, Vilim
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undisturbed soil columns ,hillslope ,Brilliant blue ,potassium bromide (KBr) ,water flow - Abstract
Hillslope soils are especially challenging due to larger possibilities of soil erosion which can lead to soil heterogeneity and result in nonlinear water flow and solute transport. Thus, to determine water flow and possibly quantify preferential flow we conducted a soil column study within the first Croatian critical zone observatory SUPREHILL. The research was conducted in controlled conditions on undisturbed soil columns (25 cm depth and 16 cm in diameter) taken from the hilltop, middle and hillbottom positions. Since soil hydraulic properties are impacting water flow and thus the solute transport, undisturbed soil cores (250 cm3) were taken from the hilltop, middle and hillbottom in three repetitions and the soil hydraulic properties were estimated using HYPROP and WP4C. After application of 150 mL tracer (potassium bromide, KBr) at concentration of 1g L‒1 KBr, columns are irrigated. Soil moisture is measured with soil moisture sensor on 7 cm depth and tensiometer on 17 cm depth set inside each soil column. At the end of the column, the leachate is collected to determine Br‒ in water samples which helped us to determine dispersivity coefficient and water flow behaviour. Furthermore, to identify preferential flow we applied Brilliant blue dye tracer on the top of the soil columns, afterwards the columns are photographed. Quantification of preferential flow was conducted in ImageJ software using image analyses procedure. First results are showing the fastest water flow in the soil column taken from the middle part of the hillslope which is in line with hydraulic conductivity values obtained using HYPROP and WP4C. In the future, we plan to expand the research by applying KBr and Brilliant blue in the field, as well as by taking undisturbed soil samples for CT scanning and numerical simulations which will give us more specified information about preferential flow and nonlinear dynamics.
- Published
- 2022
6. Soil Water Flow Evaluation at Top, Middle and Bottom Position at the Vineyard Hillslope
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Defterdarović, Jasmina, Krevh, Vedran, Filipović, Lana, Han, Luka, Kovač, Zoran, and Filipović, Vilim
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vineyard soil ,hillslope ,water flow ,subsurface flow - Abstract
In the soil vadose zone, one of the critical processes is the water flow which is important for the root uptake but could also enhance transport of potentially harmful agricultural substances to surface and groundwater. Thus, we established the first Croatian critical zone observatory SUPREHILL to specify subsurface preferential flow and nonlinear agrochemical transport processes. Among other instruments, wick lysimeters were installed at the 40 cm depth at the top, middle, and bottom of the vineyard hillslope. The water volumes collected in lysimeters were measured every two weeks. For estimation of soil hydraulic properties (SHP) using HYPROP and WP4C techniques, the undisturbed soil cores (250 cm3) were taken from the same positions at 1520 and 3540 cm depth in three repetitions. The first results from one-year research showed the highest amount of water collected in lysimeters at the hilltop and the lowest at the middle part of the hillslope. Estimated SHP showed that the middle position mostly has the highest values of bulk density and the lowest values of porosity which could cause slower vertical water movement. Furthermore, the water volume in lysimeters could be a result of variable slope in the investigated hillslope. For example, the slope on the top is minor compared to the middle and the bottom thus resulting in the slowest lateral subsurface flow and the highest amount of collected water. The middle and the bottom have similar slopes, but below the bottom position, the slope becomes less steep affecting the water movement at that position and reducing lateral subsurface flow causing a higher amount of water compared to the middle part. At the middle position, the subsurface runoff is possibly the main water pathway since the middle part has a steep slope that continues to the bottom of the hillslope. Thus, to precisely determine water movement at vineyard hillslope and therefore the agrochemical transport, later in research we will combine results obtained by sensors set at the field at various depths, undisturbed soil columns experiments, CT-scanning, and numerical simulations.
- Published
- 2022
7. Estimation of soil hydraulic properties and preferential flow at agricultural hilllslope under controlled conditions
- Author
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Defterdarović, Jasmina, Filipović, Lana, Kovač, Zoran, Krevh, Vedran, Han, Luka, Kodešová, Radka, Gerke, Horst, and Filipović, Vilim
- Subjects
SHP ,PF ,hillslope ,experiment ,SUPREHILL - Abstract
Soil vadose zone is one of the most complex terrestrial systems due to various processes occurring within its boundaries. The first Croatian critical zone observatory SUPREHILL was established to specify subsurface preferential flow and nonlinear agrochemical transport processes. Combining laboratory and numerical methods with extensive sensor-based equipment will result in a wide range of data allowing us to accurately estimate heterogeneities on a local scale. The presented study includes estimation of soil hydraulic properties (SHP) and water flow experiments under controlled conditions. Undisturbed soil cores (250 cm3) were taken in three repetitions at the top, middle and the bottom of the hillslope to estimate SHP using the HYPROP and WP4C techniques. Undisturbed soil columns were taken at the hilltop, middle, and the bottom of the vineyard hillslope from the row and interrow area. Soil columns are 25 cm high and 16 cm in diameter with soil moisture sensors and tensiometers set inside each column. Each soil column was irrigated three times per day during two-week period. Results obtained using HYPROP showed very similar SHP in the investigated depth which indicates uniform soil structure along the hillslope (top soil layer). HYPROP derived SHP showed very low values of hydraulic conductivity, but the sensors in columns reacted shortly after irrigation which indicates higher hydraulic conductivity. Since soil cores for HYPROP are relatively small compared to the soil columns, the presence of preferential flow is minimal, and some flow pathways present on the larger scale are not accounted for. Therefore, preferential flow will be further identified and quantified using a dye tracer, and experimental results will be shown. For additional preferential flow identification and quantification, later in the research, we will combine CT-scanning of undisturbed soil columns and numerical simulations.
- Published
- 2022
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