WP1 – Taxonomic and functional diversity of the soil microbiome (lead: Agroscope; co-lead: LSU):
Goal: WP1 identifies and quantifies the taxonomic and functional diversity of the soil microbiomes
at the various sites investigated.

Methods: Diversity of the soil microbiome is determined using a metabarcoding approach based on next generation sequencing (NGS) on an Illumina platform. Phospholipid and neutral lipid fatty acid (PLFA, NLFA) analyses are performed to provide information on abundance and biomass of each microbial domain and functional group (Olsson 1999; Frostegard and Baath 1996; Olsson et al 1995), which is used for obligatory validation of NGS data. For this, PLFAs and NLFAs are extracted from soils and identified and quantified by gas chromatography.

WP2 –Functional potential of the soil microbiome (lead: Hohenheim; co-lead: Portugal):
Goal: WP2 assesses the functional potential of the soil microbiome across the assayed management and agro-climatic gradients.

Methods: Soil organic matter decomposition is generally mediated by a complex set of extracellular enzymes produced by soil prokaryotes and fungi. Hence, to capture this enzymatic complexity, an array of relevant enzymes in the N (e.g., proteases, peptidases, urease, chitinase), C (glycosyl hydrolases, oxidases, peroxidases) and P (acid and alkaline phosphatases; and phosphoesterases) cycles are included in the microbial activity assessment. These hydrolytic enzymes are assayed on the basis of a high throughput, substrate-based microplate approach (Marx et al 2001).