Effect of Azotobacter chroococcum K2020 on the agronomic performance of cotton (Gossypium hirsutum L.)

In the saline soils of Karakalpakstan, the agronomic potential of the nitrogen-fixing strain Azotobacter chroococcum K2020, isolated from the indigenous microbial community, was evaluated under field conditions. The aim of this study was to assess the effect of this strain on the growth, development, and yield performance of several cotton (Gossypium hirsutum L.) varieties.
Due to its ability to fix atmospheric nitrogen, A. chroococcum serves as a promising tool for sustainable and environmentally friendly agricultural practices. The reduction in the use of synthetic nitrogen fertilizers not only improves soil health but also enhances ecological sustainability.
A field experiment was conducted at the research site of the Institute of Genetics and Experimental Plant Biology using a randomized complete block design (RCBD) with two replications. The tested cotton varieties included “Bukhara-102,” “Gulbahor-2,” “UzRFA-709,” and “UzRFA-710.” Seeds were inoculated with a bioformulation based on the A. chroococcum K2020 strain and compared to non-inoculated controls.
The results demonstrated that inoculation stimulated both vegetative and reproductive development. The highest efficacy was observed in the “UzRFA-710” variety, which showed the greatest plant height and number of bolls. Plant height measurements were as follows:
“UzRFA-710”—125.18 ± 0.81 cm, “UzRFA-709”—118.64 ± 1.22 cm, “Gulbahor-2”—120.22 ± 1.44 cm, and “Bukhara-102”—110.40 ± 1.61 cm.
Improvements in fiber quality and yield were also recorded following inoculation. The observed biological effects are attributed to the strain’s nitrogen-fixing capacity, synthesis of phytohormones (auxins and gibberellins), and enhancement of plant resistance to abiotic stresses.
Thus, the application of Azotobacter chroococcum K2020 represents a promising direction for the development of eco-friendly biotechnologies and may contribute significantly to sustainable cotton production.