Double Advantages of Nutrients and Biostimulants Derived from Sewage Sludge by Alkaline Thermal Hydrolysis Process for Agricultural Use: Quality Promotion of Soil and Crop

Abstract

Low‐carbon alkaline thermal hydrolysis of sewage sludge for the production of high‐quality plant‐growth‐promoting nutrients and biostimulants is a growing concern for sludge resource utilization in agriculture. Thus, this study aims to investigate functional characteristics and soil biochemical effects of sewage sludge‐derived nutrients and biostimulants (SS‐NB). The content of heavy metals in SS‐NB decreased by 47.39–100%, and an increase in soil protease, invertase, and soil nutrient utilization rates are observed in SS‐NB groups. SS‐NB substituted for chemical fertilizer increased the diversity and evenness of microbial community and reduced the abundance of the soil‐borne bacterial genus Arthrobacter. The dominant community of SS‐NB100 group is mainly enriched in Microvirga, Ensifer, Novosphingobium, Bosea and Ellin6055, which are principally beneficial symbiotic bacteria of plants and participated in C and N cycles. Moreover, SS‐NB reduced the accumulation of Ktedonobacteria and Nitrosospira, which are involved in the production of CO2 and N2O, and also enhanced the coordination of soil microorganisms with enzyme activities and nutrient utilization rate. In conclusion, the results suggest that SS‐NB exerts a positive effect on reducing greenhouse gas emissions and preventing soil‐borne diseases, and can further enhance collaboration with soil enzyme activity and soil nutrient utilization by stimulating soil microorganisms.

Definition of Dispersion Objects in the Microbial Conveyor Belt: Extending from Life Science to Environmental Science

“…Specifically, during the land use of the AS, live microorganisms are introduced into the soil system through the sub-MCB, and these introduced microorganisms synergize with those present in the soil system. Additionally, the introduction of the AS substantially enhances the abundance of beneficial bacteria, such as Azospirillaceae, Azospirillales, and Saccharimonadales, known for promoting plant growth and increasing phosphatase activity, as well as Beijerinckiaceae, Microvirga , and Ensifer , which exhibit nitrogen-fixing abilities . In this microorganism-centric sub-MCB from the AS to soil, functional microorganisms are transferred and enriched within the subsystem, leading to advantageous effects on the donor system, which can be categorized as “probiotics”.…”