LAUSR

Abstract Modern agriculture involves the use of synthetic compounds (agrochemicals) in order to maximize crop yields. However, inappropriate fertilization and/or the use of pesticides can have adverse effects on crop productivity and quality. In this context, a study has been carried out to ascertain the effect of increasing dosages of a chemical fertilizer (Greenhouse Special) and some widely used pesticides on tobacco plants. To this purpose biomass, chlorophyll contents and the concentration of NO3 − and NH4 + were determined. Results showed that NO3 − and NH4 + significantly accumulated in tobacco plants following the application of the two the highest fertilizer dosages. Furthermore, some pesticides altered NO3 − and NH4 + concentration in leaves. Finally, in order to estimate the effect of these compounds on nitrogen acquisition and metabolism, Nitrogen Use Efficiency was evaluated. Data of NUE evidenced that the optimal dosage of fertilizer was 0.250 g/plant. Moreover, it was found that the active ingredients of pesticides affected NUE in the species studied.