Monika Zovko

Trace metals in the coastal soils developed from estuarine floodplain sediments in the Croatian Mediterranean region

Fertile soils in the River Neretva estuary were developed by fluvial sedimentation and deposition of the eroded soil material from the karst hills within the catchment. After extensive reclamation, two reclaimed land zones (fluvial terraces and lower-laying terraces) have been delineated, both used for agriculture. The main objectives of this study were to evaluate soil chemical and geochemical properties in reclaimed zones that differ mainly in topography, soil types and agricultural land use. The origin of the trace metals in the arable soils was studied using multivariate statistics, and interpolation maps of trace metals were produced using GIS and geostatistics. Soil trace metal concentrations do not exceed a threshold value established by the Croatian Government regulation, with exception of copper. Comparative analysis of the main soil properties and trace metal concentrations in the study area showed a pronounced spatial variation and differences between two reclaimed zones in soil organic matter content, bioavailable P and total concentrations of Cd and Cu. Factor analysis in the area of the lower-laying terraces showed grouping of bioavailable P and K, organic matter content and pH (negative loading) in the component associated mostly with the land use. In the area of the fluvial terraces, bioavailable P and total Cd were grouped in the same component that may be explained by the traditional small farm agriculture and overuse of mineral fertilizers. In the whole study area, processes of secondary salinization were determined, accompanied by the raised chloride and sodium concentration measured in the saturation soil extract.

Soil Contamination by Trace Metals: Geochemical Behaviour as an Element of Risk Assessment

Metal pollution in soils, especially agricultural, has become serious problem worldwide, which poses serious threats of entering potentially toxic metals into the food chain. This chapter reviews the concept of trace metals geochemical behaviour in soil and methods of their bioavailability assessment. Special emphasis was given on soil biogeochemical properties, ecological conditions, and plant characteristics that can modify the bioavailable fraction of metals in the soil–plant system. Constraints on the use of different approaches to assess the mobile and bioavailable fraction of trace metals in soil are shown related to the chemical properties of given elements, different soil characteristics and different ecophysiological processes in the rhizosphere. Metal bioavailability is a complex issue that depends on a series of properties appertaining to the soil matrix, plant properties and environmental conditions. An interdisciplinary approach is therefore required to carry out risk assessment studies. The example of using mathematical model and geostatistics in assessment of soil contamination by trace metals is given.

Comparative study of methodologies to determine the antioxidant capacity of Al-toxified blueberry amended with calcium sulfate

Blueberry (Vaccinium corymbosum L.) is well adapted to acidic soils where aluminum (Al3+) can be linked to oxidative stress and antioxidant capacity (AC). Calcium sulfate (CaSO4) is used to alleviate Al3+ because it does not alter soil acidity. However, the role of Ca addition in AC, based on a single electron transfer reaction (SET), remains unknown.The aim was to evaluate the AC using SET methodologies, i.e., 2,2-diphenyl-2-picrylhydrazyl (DPPH), 2,2´-Azinobis-bis (3 ethylbenzothiazoline-6-sulphonic acid) (ABTS) and ferric reducing-antioxidant power (FRAP). Blueberry cultivars Elliot and Jersey were grown and exposed to the following treatments for 15 days: Control (nutrient solution alone, pH 4.5); control+Al (Al); control+Al+Ca (Al+Ca) and control+Ca (Ca). The Ca and Al concentrations, total phenol (TP) content and radical scavenging activity (RSA) were evaluated at 7 and 15 days. The Al+Ca and Ca treatments increased the Ca concentration in the leaves (22%) and roots (40%) of both cultivars compared with the control. The Ca in the tissues varied with cultivar and time. After 15 days, increases in TP, DPPH, ABTS and FRAP were detected. The cultivars showed positive relationships between the TP and AC in the leaves and roots. Thus, CaSO4 is an important tool to improve the AC in Al-stressed fruit crops grown in acid soils.

Improvement of Vineyard Management of Vitis vinifera L. cv. Grk in the Lumbarda Vineyard Region (Croatia)

The vine-growing region of Lumbarda, located in the southeastern part of the island of Korcula, Croatia, has deep sandy soils (paleodunes) associated with the Mediterranean climate and provides optimal conditions for cultivating the autochthonous vine variety Vitis vinifera L. cv. Grk. Unfortunately, recently growers have noted declining yield and quality of grapes resulting from inadequate vineyard management (particularly unsustainable management of soil organic matter) and the occurrence of viral diseases. To revitalize and maintain the vineyards in the Lumbarda region, a detailed study was carried out involving intensive soil survey, analysis of grapevine nutrient status, positive clonal selection, and establishment of new vineyards with virus-free plant material. Preliminary soil survey results provided insight into the extent of variability in major physical and chemical soil characteristics. Based on these results, eight markedly different vineyards were selected for detailed analysis of grapevine nutrients [boron (B), calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P), and zinc (Zn)] at key development stages to detect potential imbalances that may hamper vine growth and affect its production. Leaf blades and petioles were sampled at midflowering and midveraison stages during the 2007–8 growing season from each of the selected vineyards. The greatest variability in nutrient content between the study sites was recorded for Cu, and considerable variability was also determined for B, Mn, Mg, and P. Differences in fertilization practices are the most common reasons for this variability. The results point to B deficiency in some of the vineyards and suggest potentially toxic levels of Cu in others.

Soil and Water Management for Sustained Agriculture in Alluvial Plains and Flood Plains Exposed to Salinity: A Case of Neretva River Valley

Salinisation, desertification and pollution are the biggest threat to soil fertility in costal river valleys around the Mediterranean basins. Risk of soil degradation in coastal river valleys is determined not only by the spatial characteristics of the area that can favour saltwater intrusions, but also by the physical and chemical properties of the soils, and the type of agricultural land use. The salinisation problem may also enhance trace metals mobilization, its bioavailability and phytoaccumulation. Hence, more holistic approach has to be applied in mitigation adverse effects of salinity on plant growth in saline environments. It is therefore particularly important to monitor and determine salinisation of soils and water in order to timely propose management measures which will slow down this process and/or reduce its adverse effects. This chapter present extensive field research on soil and water salinisation and experimental research on detrimental effects of soil and water salinity on crop production and metal phytoaccumulation. The represented research program was set out to develop and validate appropriate knowledge and technologies providing an important plank in achieving strategic objectives in environment protection and sustainable development.

Hyperspectral imagery as a supporting tool in precision irrigation of karst landscapes

This research was carried out in an experimental vineyard grown in artificially transformed karst terrain (Croatia). The experimental design included four water treatments in three replicates: 1) fully watered or based on 100% evapotranspiration (ETc) application; 2) regulated deficit irrigation based on 75% and 50% ETc applications; and 3) non-watered. Hyperspectral images of grapevines were taken in the summer of 2016 using two spectral-radiance (W·sr −1 ·m −2 ) calibrated cameras, covering wavelengths from 409 to 988 nm and 950 to 2509 nm. The four treatments were grouped into two new sets: 1) drought (NO); and 2) watered (the remaining three treatments). The watered group was then split into two new sets: 1) 50% treatment; and 2) 75+100% treatment. The images were analyzed using Partial least squares – discriminant analysis (PLS-DA), and Single Vector Machines (SVM). The PLS-DA demonstrated the capability to determine levels of grapevine drought or watered groups with 70 - 80% accuracy. A similar success rate was achieved in distinguishing the 50% group from the 75+100% group.

Harmonization of agricultural intensification with long-term ecological integrity in Croatia

Rural areas in Croatia have great resources in the shape of natural assets and landscapes, which is an excellent basis for the economic development and rural employment. In this context, integrated water resources management is an issue of high significance. The prevailing system of uncoordinated water resources management cannot sustain the increasing water needs of the various expanding factors. This study focuses on the activities cut across the rural, environmental and socio-economic issues of water resource management in Zadar region (Croatia). The problems associated with inadequate management of natural resources have to be solved systematically by a participatory approach established on several key issues: (1) agricultural development with strengthening farmers’ organization, (2) rural infrastructure by investment in irrigation infrastructure, and (3) irrigation related environmental and social measures. The review of institutional and legislative support to optimize performance of the irrigation system was done, as well as the measures that promote sustainable use of natural resources.