Long-term liming promotes drastic changes in the composition of the microbial community in a tropical savanna soil

We characterized soil bacterial and archaeal communities under native Cerrado vegetation and their responses to increases in soil pH. The experimental area was subjected to lime additions for eight consecutive years, followed by an 11-year interval and an additional lime application. We collected soil samples in the rainy and dry seasons of 2017 (representing the 11-year interval from the last liming) and 2018 (representing short-term effects, 4 and 9 months after we resumed the liming). We studied the microbial communities of soil samples from control and treatment plots (liming) through 16S rRNA gene sequencing. We found that microbial community profiles differed by treatment and sampling period, suggesting long-term effects of liming and the strong influence of Cerrado's seasonal dynamics. Samples from liming treatment had a higher bacterial diversity than the control treatment, while the archaeal community showed the opposite response with lower diversity. Different from diversity estimators, enzyme-encoding genes for C, N, and S metabolic pathways showed a reduction in abundance in the liming treatment. The effects of liming on the soil microbial community under Cerrado vegetation are long-lasting. Despite the increase in diversity, the predicted functional profiles suggested a potential reduction on soil multifunctionality.

Automated summary

The study revealed significant impacts of soil pH increases on soil bacterial and archaeal communities under native Cerrado vegetation. Lime additions resulted in higher bacterial diversity and lower archaeal diversity, along with reduced abundance of enzyme-encoding genes for C, N, and S metabolic pathways.