USE OF ISOTOPIC TECHNIQUES TO EVALUATE FOLIAR FERTILIZATION EFFICIENCY

In this study, the foliar fertilization efficiency was assesed by using nuclear techniques and the stable isotope 15N. The objective was to increase nitrogen use efficiency in plants. In addition, the mobility of nitrogen in plants was evaluated. The environmentlly friendly impact of this type of fertilizer is supported by means of an increase in nutrients uptake from the natural soil supplies, and as a result of foliar fertilization. The trials were conducted in INCDPAPM-ICPA Bucharest greenhouse, using sunflower as test plant. To evaluate the mobility of nitrogen in plants, a PK with mezo and microelements (Mg, S, Fe, Cu, Zn, Mn, Co, Mo) foliar fertilizer was enriched with labeled 15N and unlabeled N, using urea and ammonium nitrate as nitrogen sources. Therefore, 6% of the total nitrogen content was represented by the 15N labeled isotope (in all three forms: ammoniacal,15N-NH4, nitric , 15N-NO3 and amide, 15N-NH2). The obtained results suggest that nuclear techniques can be successfully used in agrochemical research to deepen plant nutrition and nutrients translocation studies