Mineral and organic growing media have distinct community structure, stability and functionality in soilless culture systems

TLDR

Soilless growing medium choice is critical for plant nutrition, growth, and eco‑sustainability in horticulture. The study examined how microbial communities develop in organic versus mineral soilless media, aiming to identify temporal factors and taxon distribution influencing community composition and potential functionality. High‑throughput sequencing was employed to track microbial community composition over time in organic and mineral media, comparing taxon distribution and potential functional roles. Sequencing showed that the organic medium harbored a distinctive, temporally stable microbial community driven by humidity, pH, nitrate‑N, ammonium‑N, and conductivity, with ammonium‑N linked to Rhizobiaceae abundance and competitive interactions among Methylophilaceae, Actinobacteridae, and Rhizobiaceae, suggesting that such unique, stable communities could enhance resistance to external forces and inform sustainable horticulture strategies for higher productivity and quality.

Abstract

Abstract The choice of soilless growing medium for plant nutrition, growth and support is crucial for improving the eco-sustainability of the production in horticultural systems. As our current understanding of the functional microbial communities inhabiting this ecosystem is still limited, we examined the microbial community development of the two most important growing media (organic and mineral) used in open soilless horticultural systems. We aimed to identify factors that influence community composition over time and to compare the distribution of individual taxa across growing media and their potential functionality. High throughput sequencing analysis revealed a distinctive and stable microbial community in the organic growing medium. Humidity, pH, nitrate-N, ammonium-N and conductivity were uncovered as the main factors associated with the resident bacterial communities. Ammonium-N was correlated with Rhizobiaceae abundance, while potential competitive interactions among both Methylophilaceae and Actinobacteridae with Rhizobiaceae were suggested. Our results revealed that soilless growing media are unique niches for diverse bacterial communities with temporal functional stability, which may possibly impact the resistance to external forces. These differences in communities can be used to develop strategies to move towards a sustainable horticulture with increased productivity and quality.