Dataset for substrate stoichiometry drive the divergent accumulation of plant and microbial necromass carbon

To optimize the conversion of exogenous C into soil organic C, we manipulated the substrate stoichiometry (SS) match the requirements ranging from oligotrophs to copiotrophs. We assumed the stoichiometric ratios of fungi (C:N:P:S=10,000:1034:110:94) and bacteria (C:N:P:S=10,000:2004:494: 264) reflected substrate requirements of oligotrophs and copiotrophs. This study provided different SS levels by applying varying amounts of straw and N, P, and S. A total of five treatment groups were established: straw‑amended soil with no nutrient addition (NPS0), NPS0 with nutrient additions to meet the metabolic requirements from fungi (NPS1) to bacteria (NPS3), and a control soil (CK). The straw, cut into 2–5 mm pieces, was mixed with soil at a rate of 2 g per 100 g dry soil. The SS was regulated by adding or not adding the nutrient solutions (NS1, NS2 or NS3) containing ammonium nitrate, potassium dihydrogen phosphate, and ammonium sulfate (pH = 7). The concentrations of N, P, and S in NS1 were 6.42, 1.79, and 0.95 g L−1, in NS2 were 19.50, 3.52, and 1.90 g L−1, and in NS3 were 30.72, 9.98, and 4.23 g L−1, respectively. Topsoil (0–20 cm) and subsoil (20–40 cm) samples (8 kg each) were collected, sieved at 2 mm, and air-dry. The SS was regulated by adding 1 ml of NS1, NS2, or NS3 to 100 g of dry topsoil on a clean and smooth plastic sheet. The soil moisture was then adjusted to 60% field capacity with distilled water, followed by the addition and mixing of 2 g straw fragments. The mixture was then transferred to nylon mesh bags and sealed (aperture: 0.048 mm, length: 20 cm, and width: 15 cm). The subsoil was treated in the same manner. Nine replicates were maintained for each treatment for both topsoil or subsoil. Three soil pits (length: 1.5 m, width: 0.5 m, depth: 0.4 m) spaced at 0.6 m apart were dug in the field, and the topsoil and subsoil were stored separately. Three replicates of each treatment for subsoil were arranged in two rows (spaced approximately 20 cm) and vertically placed at 20–40 cm in each pit. Each pit was backfilled with the original subsoil. The same procedure was followed to fill the pits with the replicates of the five treatments for topsoil. All replicates from one pit were collected at 30, 90, and 150 days post-sowing, then brought back to the laboratory with dry ice and stored at –80℃. This study primarily investigated the following parameters: including (1) amino sugars, lignin phenols, soil water content, soil organic C (SOC), available N (AN), and available P (SAP); (2) C, N, and P cycling enzyme activities (cellobiohydrolase (CBH), β-glucosidase (BG), L-leucine aminopeptidase (LAP), β-N-acetylglucosaminidase (NAG), and acid phosphatase (AP)); and (3) bacterial and fungal diversity and community composition at the phylum level. The main statistical analyses employed included one-way ANOVA, principal coordinates analysis (PCoA), and random forest models.