Soil sampling
For soil microbiome and nutrient pool studies, we collected soil samples
from the four sampling sites along the altitudinal gradient during the
peak vegetation season (June-July 2019). At each site, we collected soil
samples in triplicates from the invaded (IN) plot and one sample from
uninvaded (UN) plot which served as a control. To maintain the viability
of the soil microbiota sampled at each site, we employed proper soil
collection and storage protocols (McPherson et al., 2018). For each
sample, we collected ca. 1000g of soil using sterilized gloves and
placed them in sampling bags. Digging equipment was also sterilized with
bleach and ethanol after each soil sample collection to avoid any
possible cross-contamination of soil biota. The collected samples were
immediately transported to the laboratory and processed in less than 6
hours after collection from the field. All the visible macrobiota and
roots were removed from the soil and sieved using a mesh of 2mm pore
size. The sieved soil samples for the microbiome studies were stored in
50 ml tubes and kept inside deep freezer at -80ºC, while as, for
nutrient studies all the soil samples were air dried and stored at -4ºC
till further analysis.