Effect of soil particle size on copper availability

This paper deals with the effect of soil particle size on copper availability. Twelve vineyards, (at three depths) all on the territory of the Vojvodina Province, were observed for soil contamination with copper. Soil samples were taken in four locations (5 soil types). The samples were analyzed for total copper and available copper (in EDTA). and sequential extraction was conducted. Correlations between soil particle size and copper fractions were calculated and analyzed. The obtained results indicated that the increase in the portion of smallest soil separates, clay and silt, tended to reduce copper availability, whereas the larger separates tended to increase it. The available fractions, C u e x and C u c a r , were significantly negatively correlated with the content of clay and silt along the entire soil profile of the analyzed vineyards. Simultaneously, these two factions were positively correlated with the content of fine sand, also along the entire soil profile. The results confirmed that, when assessing the extent of soil contamination with copper, soil mechanical composition should be taken into account as an important factor of copper availability

ECONOMIZING THE FERTILIZATION PRACTICE IN THE CONDITIONS OF GLOBAL CRISIS

Use of fertilizers keeps increasing on the global scale, primarily because of increased fertilizer use in developing countries. In conditions of the global economic crisis, the portion of expenditures for mineral fertilization increases within the total price of main field crops. Nitrogen fertilization cannot be omitted because of specific properties of this macronutrients (migration down the soil profile). Low humus content was found in a large number of soil samples taken on the territory of the Vojvodina Province. This calls for a more intensive application of organic fertilizers and restraint from the practice of burning harvest residues. Phosphorus and potassium fertilization may be optimized if soil analyses show that the levels of these macronutrients are above the optimum level (a minimum of 15 mg/100 g of soil). Length of period during which phosphorus and potassium fertilization will be omitted depends on the actual levels of these elements in the soil and crops grown