# Synergistic effect of Trichoderma harzianum and chitosan nanoparticles on garlic plants in arid regions

## TL;DR

Combining Trichoderma harzianum and chitosan nanoparticles improves garlic growth and yield in arid regions, offering a sustainable alternative to agrochemicals.

## Contribution

Demonstrates the synergistic effect of combining Trichoderma and chitosan nanoparticles for sustainable garlic cultivation in arid regions.

## Key findings

- Inoculation with T. harzianum and 100 ppm chitosan increased plant height, bulb weight, and diameter.
- The combination enhanced nutrient uptake and antioxidant levels in garlic plants.
- This treatment significantly improved physiological and growth parameters compared to other treatments.

## Abstract

The intensive use of agrochemicals is not conducive to sustainable agricultural production, as it leads to soil degradation, harms soil organisms, and causes environmental pollution. Hence, adopting natural and biological practices in plant production management is a sustainable and environmentally friendly strategy. Therefore, this study investigated the effectiveness of combining Trichoderma harzianum inoculation and chitosan nanoparticle spraying in garlic cultivation, where two levels of T. harzianum inoculation (inoculated and uninoculated) and three levels of nano-chitosan spraying (0, 50, and 100 ppm) were used in an open-field experiment. Overall, Trichoderma fungi and chitosan nanoparticles, either alone or in combination, increased nutrient uptake, improved physiological status, promoted plant growth, and increased garlic yield. However, garlic plants inoculated with T. harzianum and sprayed with 100 ppm chitosan nanoparticles presented superior results over all the other treatments, increasing nutrients (N, P, K, and S), photosynthetic pigments (chlorophyll a, b, and carotenoids), and antioxidants (phenolic compounds, flavonoids, and vitamin C), resulting in significant increases in plant height (16%), bulb fresh weight (22%), bulb diameter (15%), and bulb dry weight (25%). These findings suggest that microbial and natural biostimulants, such as Trichoderma and chitosan, can be considered successful and sustainable agricultural practices to increase physiological performance, bioactive compound accumulation, and yield of vegetable plants.

The online version contains supplementary material available at 10.1186/s12870-025-07844-5.