Examining the soil bacterial community under the combined influence of water-absorbing polymer and plant subjected to drought stress

The use of water-absorbing polymers (WAP) in soils for mitigating water stress is well known. However, the influence of WAP on the soil microbiota and hence, plant growth in soils. The objective of this study is to quantify the combined influence of water absorbing polymer (WAP) amendment and vegetation on the bacterial community of an agricultural soil when subjected to drought conditions.

In this study, two WAPs along with the plant species Phaseolus vulgaris L. (common bean) were considered to study its impact on the soil bacterial community under controlled environment conditions (greenhouse). The soil bacterial community was assessed using 16 S rRNA gene sequencing at three stages of bean growth. Additionally, energy-dispersive X-ray (EDX) analysis was performed to identify soil constituents and their correlation with bacterial changes.

Results demonstrated significant alterations in bacterial community composition and diversity with WAP application. Notably, the combined effects of WAP and plant species under drought resulted in a synergistic interaction between plant development and treatment. Enrichment of Proteobacteria, Gemmntinonadetes, Verrucomicrobia, and Bacteroidetes was observed, while Actinobacteria, Chloroflexi, and Planctomycetes showed a decreasing trend. Furthermore, WAP amendment in the presence of plants led to increased nitrogen (5.8%), phosphorus (1.9%), and potassium (7.35) (NPK) concentrations in the soil.

These findings highlight the significant positive impact of WAP as a soil amendment on the bacterial community and improved nutrient availability (carbon cycle, nitrogen cycling and fixation, phosphorus availability) in the soil matrix, thereby promoting sustainable agricultural practices.