Improving the growth traits and essential oil of basil plants by using mineral N and some biostimulant substances

The present work was carried out during the two successive seasons of 2020 and 2021 at the Experimental Farm, Faculty of Agriculture, Al-Azhar University, Assiut, Egypt to investigate the impact of applying mineral N and foliar spray with some biostimulant substances, as well as their interactions between plant growth traits and essential oil percentage of basil (Ocimum basilicum) plants. Eleven N mineral and/or biostimulant substance treatments, as follows: control, 100 % N as ammonium nitrate (33.5% N) at 300 kg/acre, 75% N (225 kg/acre), moringa leaf extract (MLE) at 5 g/l, MLE at 10 g/l, yeast extract (YE) at 5 g/l, YE at 10 g/l, 75% N + MLE at 5 g/l, 75% N + MLE at 10 g/l, 75% N + YE at 5 g/l and 75% N + YE at 10 g/l. The obtained results cleared that the application of N fertilization and biostimulant substances, either separately or together led to a significant increase in growth parameters (plant height, branch number/plant, herb fresh and dry weights/plant and leaves fresh and dry weight/plant) and, also essential oil % in the three cuts, except for 5 g/l MLE and 5 g/l YE mostly, in these aspects among all cuts particularly the first and second cuts, in relative to the check treatment. Additionally higher values of the studied traits were detected due to combined treatments then those given by single ones, mostly. Obviously, the use of the combined treatment (75% N + 10 g/l YE) and the combined one (75% N + 10 g/l MLE) gave the highest values of the examined characteristics, mostly, among all cuts.