Grassland soil fungal and bacterial community responses to drought and compost amendments
One major stressor of grassland ecosystems is prolonged drought, leading to decreasing plant productivity and altered soil microbial activities which may in turn affect nutrient and carbon cycling. Soil organic amendments, such as compost, can be used to enhance soil fertility and mitigate drought effects. Here we evaluated the responses of fungal and bacterial communities to a 3-year-long experimental drought and compost treatment in two Swedish grasslands. The experimental treatments started in 2019. Each grassland included both an upper and a lower catenary position, and samples were collected from four soil depths ranging from the surface to below the rooting zone. We hypothesized that drought and compost addition would shift fungal and bacterial community composition, with contrasting effects on microbial abundance and diversity. Fungal communities were identified using PacBio sequencing of ITS2, and for bacterial communities we used Illumina sequencing of 16S. Fungal and bacterial data from the pre-treatment study are available in the NCBI Sequence Read Archive (www.ncbi.nlm.nih.gov/sra) under the accession number PRJNA938302.