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Spatial assessment of key soil properties is a basic prerequisite for the evidence-based decision making and sustainable use and management of soil. The aim of this work was to estimate the spatial distribution of SOC under different types of land use, by the means of Digital Soil Mapping techniques. A site-specific soil data collection for the Ohrid valley was integrated with continuous and discrete datasets of environmental covariates, serving as predictors. The selected test area outlines the variability of factors influencing the SOC content and spatial distribution. Soil sampling locations were randomly distributed within a predefined mesh with a 1-sq.km spatial resolution and further stratified to outline different types of land use within each mash square. Soil samples were collected from 93 locations at three depths, each 20 cm apart, covering the total area of 10 thousand ha of arable land, forestland, and land under natural vegetation. A set of additional environmental dataset was collected, namely the soil map, land use map, geology map, digital terrain model and its derivatives, satellite images, climate data, as well as a set of indices NDVI, SAVI, BI etc., developed from the remote sensing datasets. Multiple linear regression was used for evaluating the regression pattern between the environmental predictors and the target variable. To estimate spatial variability, several regression tree methods were used. The results obtained using this approach have given a better spatial overview of the most vulnerable areas regarding SOC depletion. Out of 21 locations examined, the content of soil organic carbon in the top layer (0-20 cm.) of forestland was on average 6.81%, while at 22 locations examined under grassland, the average content was 4.07%. The arable land, which is under continuous human impact, had the lowest content of SOC of 2.5% under field crops and 2.61% under perennials.

The foliar fertilization has been used as an important agrotechnical measure to avoid deficiencies and to improve quality. During the three consecutive years, a study has been performed on Vitis vinifera L. (cv. 'Cardinal') to examine whether a yield and grape berry quality have been affected by the foliar application of Ca and N fertilizers. A liquid mineral fertilizer containing 40% Ca(NO₃)₂ as Variant I and 31% N with 0,015 % Fe-chelate; 0,01 % Mg - chelat as Variant II (in text) has been sprayed four times during the growing period (before and after blooming, buckshot berries, and verasion). Results showed that foliar application of calcium and nitrogen increased the yield of table grapes in all three years of research, in comparison with a control variant. The highest yields of grapes in all three years of investigations were achieved in Variant II - 4.57 kg/vine (14.85 t/ha). During the tree years of investigations, the largest mass of grape bunch and berries were recorded in Variant II (382g and 368.68g), while the lowest cluster weight was in the control variant (344g and 330.92g). With a reference to the mechanical properties of the grape berries, the highest resistance to pressure (2229.70g) and breaking resistance (364.52g) were found in Variant I, treated with Ca fertilizer. The foliar application significantly affects the mechanical properties (resistance of the berry to pressure and breaking), especially in Variant I. The application of different types of foliar fertilizers did not have any significant effect on sugar contents and total acids, compared with the control variant

This research studies the copper contents in vineyard soils under vineyards affected by the long-term use of copper-based fungicides and evaluates the extent of this influence on the super accumulation in the main viniculture growing regions in North Macedonia. The soil samples were taken from individual vineyards located in the Tikvesh region, from two depths: 0-30 and 30-60 cm. At the same time, control samples were collected from each of the visited sites. The control samples were taken from untreated nearby locations under natural conditions in order to determine the background concentrations. The available copper (Cu) contents were analysed on soil samples taken from 100 locations, 50 of which represent vineyard soils (organic and conventional farming) and 50 control samples from nearby forests and sites. The main finding is that the average available copper concentrations are significantly higher in soils under vineyards, compared to the background concentration in control samples, especially in these with organic farming where the use of coper-based fungicides is more intensive. A comparison of the copper contents in vineyards to the background concentrations of control samples clearly confirmed the anthropogenic influence. A significantly very high level of copper (10.70-18.77 mg/kg) was measured in the soil samples from organic farming. The control samples contained a significantly lower concentration of copper, between average 1.39-1.62 mg/kg (0-30 cm) and 0.68-0.88 mg/kg (30-60 cm). According to the micronutrient rating as related to a soil test with the DTPA extraction reagent (Jones, 2001) applied in this study, a significant potential ecological risk has been noticed in the agricultural soil samples (organic and conventional production).

The aim of this study was to evaluate the foliar chelated forms of Mg and Fe, on grape yield and mineral status of the shoots of vine cultivar Cardinal. Field trials were organized using a random block system with three variants, including a control (Variant I), each replicated three times. Foliar fertilizers were applied at a concentration of 0.5% on four occasions throughout the vegetation period: before and after blooming, during buckshot berry stage, and at the verasion stage. Over the ivestigation of three years, the application of foliar Mg and Fe fertilizers significantly influenced grape yield. The variant treated with Fe (VFe) demonstrated a higher average yield of 14.87 t/ha. Furthermore, a noticeable impact of foliar fertilizers on the concentration of analyzed elements in grapevine shoots was observed. Over the three-year period, the average content of macro elements, including nitrogen, phosphorus, calcium, magnesium, and iron, was higher in the treated variants compared to the control. Additionally, results from shoot tissue analysis confirmed the existence of an antagonistic relationship between magnesium and potassium. [ABSTRACT FROM AUTHOR]

The objective of this work comprises the content of phenolic compounds in grape and wine produced by Vranec grapevine cultivar grafted on four different rootstocks (Teleki, Fercal, Rupestris Du Lot and Chasselas 41B). Total phenols, total flavan- 3-ols, total anthocyanins and total flavonoids in the grape berries, separately in seeds, pulp and skin were determined. Three months later, the same parameters were analyzed in the wine obtained by the investigated grape variety. The field investigations showed that Teleki and Fercal were more vigorous rootstocks than Rupestris Du Lot and Chasselas 41B, but there was not signifi cant deference in the phenological stages between the rootstocks. The grape clusters of Vranec grafted on Fercal and Teleki were larger than Rupestris Du Lot and Chasselas 41B. The results obtained from the laboratory analysis showed higher level of total phenols in the berries of Vranec grafted on Teleki rootstock, higher level of total anthocyanins in the berries of Vranec grafted on Chasselas 41B rootstock, higher level of total flavonoids in the berries of Vranec grafted on Rupestris Du Lot rootstock and the higher level of total flavan-3-ols in the berries of Vranec grafted on Fercal rootstock. Statistical analyses were performed using SPSS software 14.0. The differences were evaluated by ANOVA analysis through General Linear Model (GLM) procedure. After GLM analyses post hoc comparison of means were calculated by LSD (Least Significant Difference). Results were expressed at the P = 0.05 level of significance. [ABSTRACT FROM AUTHOR]