Evaluation of the Azotofertil Biostimulant as a Nitrogen-Based Fertilization Strategy for Solanum lycopersicum L. and Capsicum annuum L.

The continuous growth of the global population and the need to ensure food security require the development of sustainable agricultural technologies capable of maintaining crop productivity while reducing environmental impact. Nitrogen-fixing bacteria belonging to the genera Azotobacter and Azospirillum have attracted increasing interest due to their ability to improve plant nutrition and stimulate physiological processes associated with growth and productivity. The aim of the present study was to evaluate the effect of the commercial biostimulant Azotofertil, based on Azotobacter chroococcum and Azospirillum lipoferum, on the agrophysiological response of tomato and pepper plants, in comparison with conventional nitrogen and phosphorus fertilization. A field experiment was conducted using a randomized block design with three fertilization treatments and three biological replicates for each crop species. Soil pH, cultivable Azotobacter spp. populations, plant height, photosynthetic pigment content, vitamin C content, and total yield were evaluated. Data were analyzed using one-way analysis of variance (ANOVA), followed by Duncan's multiple range test (p < 0.05) and Pearson correlation analysis. The application of Azotofertil significantly increased the abundance of cultivable Azotobacter spp., photosynthetic pigment content, and vitamin C content, while no statistically significant differences were observed for soil pH or plant height. The most pronounced effect was observed for photosynthetic pigment content, which increased by 26% in tomato and by 21% in pepper compared to the control.