Effect of long-term mineral fertilization on soil microbial abundance, community structure and diversity in a Typic Hapludoll under intensive farming systems

ROMINA A. VERDENELLI; MARÍA F. DOMINCHÍN; CAROLINA PÉREZ-BRANDAN; ADRIÁN ROVEA; SILVINA VARGAS-GIL; JOSÉ M. MERILES

ANNALS OF APPLIED BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019 p. 363 - 375

0003-4746

Fertilizer application can not only influence plant communities, but also the soil microbial community dynamics, and consequently soil quality. Specifically, mineral fertilization can directly or indirectly affect soil chemical properties, microbial abundance and, the structure and diversity of soil microbial communities. We investigated the impact of six different mineral fertilizer regimes in a maize/soybean rotation system: control (CK, without fertilization), PS (application of phosphorus plus sulphur), NS (application of nitrogen plus S), NP (application of N plus P), NPS (application of N, P plus S), and NPSm (application of N, P, S plus micronutrients). Soil samples were collected at the physiological maturity stage of maize and soybean in March of 2013 and 2014, respectively. Overall, mineral fertilization resulted in a significantly decreased soil pH and an increased total organic carbon (TOC) compared with the control (CK). In addition, the analysis of terminal restriction fragment length polymorphism (T-RFLP) revealed that mineral fertilizers caused a shift in the composition of both bacterial and fungal communities. In 2013, the highest value of Shannon diversity of bacterial terminal restriction fragments (TRFs) was found in control soils. In 2014, NPSm treated soils showed the lowest values of diversity for both bacterial and fungal TRFs. In both crop growing seasons, the analysis of phospholipid fatty acid (PLFA) detected the lowest value of total microbial biomass under CK. As PLFA analysis can be used to evaluate total microbial community, this result suggests that fertilization increased total microbial biomass. When the bacterial and fungal abundance were examined using real time polymerase chain reaction (qPCR), the results revealed that mineral fertilization led to decreased bacterial abundance (16S rRNA), while fungal abundance (18S rRNA) was found to be increased in both crop growing seasons. Our results show that mineral fertilizer application has a significant impact on soil properties, bacterial and fungal abundance and microbial diversity. However, further studies are needed to better understand the mechanisms involved in the changes to microbial communities as a consequence of mineral fertilization