Effect of different n forms and concentrations on olive seedlings growth

Abstract

The effect of different N forms on the growth of olive seedlings in the greenhouse was studied. KNO3, NH4NO3 and (NH4)2SO 4 at different concentrations, as well as two types of substrates, sterile sand and a sand-peat mixture (1: 1), were tested. In sterile sand, with N concentrations higher than 5 mM, serious damage was observed in the plants, so concentrations of 3, 4 and 5 mM of N were used for each N salt. N-NH 4 treatments resulted in a significantly higher growth compared to KNO3 treatment. Using the peat- sand substrate and the N concentrations described above, seedling growth was higher than in sterile sand, but no differences among treatments were observed. However, the peat:sand substrate allowed application of higher N concentrations and using NH 4NO3 differences in growth were obtained, reaching the best results with 14-28 mM.