Microbial Inoculant and Polyacrylamide Jointly Improve Cotton Root-Zone Function Under Alternating...

Area of Science:

• Agricultural Science
• Soil Science
• Plant Physiology

Background:

• Alternating brackish-freshwater irrigation is a strategy to use marginal water for arid cotton production.
• This method faces challenges like soil degradation, osmotic stress, and reduced microbial activity due to salinity.
• Enhancing root-zone functioning is crucial for plant performance under such conditions.

Purpose of the Study:

• To investigate the combined effects of microbial inoculant and polyacrylamide (PAM) on cotton growth.
• To assess the enhancement of root-zone functioning under alternating irrigation with these amendments.
• To evaluate soil-root-plant interactions using partial least squares path modeling (PLS-PM).

Main Methods:

• A controlled greenhouse pot experiment with five irrigation treatments was conducted.
• Treatments included conventional irrigation (CI) and alternating irrigation (AI) with and without microbial inoculant and PAM.
• Measurements included soil properties, microbial activity, root growth, and plant nutrient uptake, analyzed using PLS-PM.

Main Results:

• Alternating irrigation reduced soil salinity (EC1:5, Na+, SAR) compared to CI.
• PAM application improved soil structure (water-stable aggregates), while microbial inoculant boosted microbial biomass carbon.
• The combined AI + microbial inoculant + PAM treatment significantly increased cotton biomass and nutrient uptake (N, P, K).

Conclusions:

• Integrating microbial inoculant and PAM effectively enhances root-zone resilience and cotton growth under alternating irrigation.
• The study highlights the synergistic effects of physical soil conditioning (PAM) and biochemical activation (microbial inoculant).
• This combined amendment strategy shows potential for improving crop production in saline soils, warranting further field validation.