ANALYSIS OF POSSIBILITIES OF REDUCING THE QUANTITY OF MINERAL FERTILIZER APPLICATION USING DIFFERENT TYPES OF ORGANIC FERTILIZERS IN CARDINAL GRAPE VARIETY

[...]the excess of minerals, especially nitrogen fertilizers, leads to the accumulation of harmful residual substances (nitrates and nitrites) in grape berries and leaves (Abd El-Wahab, 2011; Montasser et al., 2003). Since organic fertilizers contribute significantly to preserving natural resources, but also to reducing ecosystem degradation, their use in modern viticulture becomes increasingly important (Francis and Daniel, 2004). [...]with mineral fertilizers, organic fertilizers (manure, compost, green manure, worm compost and other organic sources of nutrients) are less important in the fertilization of vineyards due to chemical bound of nutrition elements with organic matter from which they are gradually released during the mineralization process (Džamić, 2000). Sugar content in grape juice is determined aerometrically (Oeschle must balance), and proportion of the total acid in the grape juice by neutralization of acids and their salts with n/10 NaOH solution using bromothymol blue indicator.