Response of Arugula to Integrated Use of Biological, Inorganic, and Organic Fertilization

This study evaluated the effects of solely and integrated application of inorganic (NPK), commercial organic (NC), and biological (MIX, mixed strains Ensifer meliloti and Azotobacter chroococcum) fertilizers on the chemical characteristics of arugula biomass and its yield, as well as changes in soil microbiological parameters after the experiment in relation to the control treatment (Ø). The experiment was performed in semi-controlled greenhouse conditions, in pots, from the 4th decade of March to the 2nd decade of September, in 2023, at three cutting times/swaths, during one agricultural season, with Vertisol soil. For soil characterization, the following parameters were analysed: granulometric composition using sieving and sedimentation procedure: soil acidity—potentiometrically: SOM—soil organic matter by Kotzmann method: total N using CNS analyser: available P—spectrophotometrically: available K—flame photometrically: total number of microorganisms on an agarized soil extract medium: fungi on a solid Czapek agar: actinomycetes on a solid Krasiljnikov agar with saccharose: Azotobacter spp. on a liquid Fyodorov medium with mannitol: ammonifiers on a liquid medium with asparagine: and dehydrogenase activity—spectrophotometrically. For plant characterization, the following parameters were determined: N and C, both on CNS analyser: P on spectrophotometer: K on flame photometer: air-dried yield biomass. A stimulative effect on all microbiological parameters was found in the treatment with integrated use of organic and biological fertilizer, except for fungi, which grew better in the treatments with separate inorganic and organic fertilizers. Generally, the stimulative impact on plant chemical parameters manifested in combined inorganic and biological, organic and biological, and inorganic and organic fertilization treatments, and was inhibited in treatment without fertilization, in all three swaths, which could also be stated for the plant yield. Positive influence of all fertilization treatments on chemical parameters was observed for the second swath in relation to the first and the third. The total yield in the NPK+MIX treatment was 121%, and in the NC+MIX treatment, it was 87% higher compared to the control (Ø). In general, integrated use of inorganic and biological, organic and biological, and inorganic and organic fertilizers, respectively, could be proposed as an optimal fertilization treatment in arugula cultivation.