Case study on agroecosystem management: Seasonal soil microbiome and maize yield response to an innovative NPK mineral fertilizer enriched with beneficial bacterial strains

The ongoing degradation of arable soils poses a serious challenge to modern agriculture , requiring novel approaches for their restoration, including the implementation of biofertilizers and microbial inoculants . Hence, we explored the potential of innovative microbiologically enriched NPK fertilizer (called biofertilizer) to stimulate the activity and diversity of soil microbial communities in two degraded soils - Brunic Arenosol (BA) and Abruptic Luvisol (AL), under maize cultivation. The two year field experiments included the following treatments - standard, optimal dose of mineral fertilizer without microbial enrichment (PC/PK) designed to meet the nutritional requirements of maize and serving as the control treatment, optimal dose amended with beneficial bacterial strains (PA100/PW100) and a dose containing 40 % less NPK fertilizer but enriched with microorganisms (PA60/PW60). The application of biofertilizer stimulated the activity of key enzymes involved in carbon, nitrogen and phosphorus biotransformations in the soil, modified the metabolic profile of soil microorganisms and changed the genetic diversity of bacteria, archaea and fungi. We observed the increased number and the presence of specific terminal restriction fragments pointing on the higher diversity within microbial communities. Next Generation Sequencing revealed that biofertilizer modified the community composition at different taxonomic levels, increased number of functional sequences assigned to metabolic processes of various compounds and higher relative abundance of fungal trophic modes and ecological guilds important for soil health. The obtained results showed that microbiologically enriched NPK fertilizer exhibits multifarious actions and has a potential to improve soil microbiome quality and diversity, as well as influencing yield of maize production. • Microbial response depends on soil type, NPK biofertilizer dose and sampling time • Biofertilizer increases maize yield by 50.12–62.47 % in Brunic Arenosol and by 2.79–15.86 % in Abruptic Luvisol • Both optimal and reduced dose of NPK biofertilzer enhanced soil enzymatic activity • NPK biofertilizer alters microbial α- and β-diversity as well as functional profiles • NPK biofertilizer shows potential in improving degraded soils quality