Interactive effects of arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria, and compost on durum wheat resilience, productivity, and soil health in drought-stressed environment

Abstract

This study examined the effects of plant growth-promoting rhizobacteria (R), arbuscular mycorrhizal fungi (M), and compost (C) on wheat growth, yield, and drought tolerance.

Methods

Conducted with a randomized complete block design, the experiment involved two different irrigation water regimes: well-watered (WW) at 75% field capacity (FC) and drought-stressed (DS) at 25% FC.

Results

DS reduced plant growth, yield, and antioxidant enzyme activity but these effects were alleviated through the application of biostimulants. Shoot dry weight increased by 187% with AMF and 159% with C, while seed number and yield improved most significantly with C, C + M, C + R, and C + M + R treatments compared to the control. The application of C, R, and M either individually or in combination effectively mitigated DS by increasing root dry matter and improving the uptake of key minerals such as phosphorus through MR and CMR treatments, by 93% and 524%, respectively. Notably, C alone or combined with M improved the auxin content by 121% and 111%, which contributed to enhanced plant development. This combination strengthened the antioxidant system (including CAT, POX, PPO, and APX), promoted the synthesis of compatible solutes, and increased soil glomalin content. These effects reduced lipid peroxidation and H₂O₂ levels, thereby improving plant resilience under drought conditions.

Conclusions

Biostimulants significantly improved soil physico-chemical properties and fertility, and enhanced the antioxidant system, including key enzymes like alkaline phosphatase, boosting overall soil health and resilience.