Stoichiometry of dissolved organic matter controls the origin of polysaccharides in dissolved organic carbon in sandy soils receiving contrasting-quality plant residues

• DOI: 10.5194/egusphere-egu24-2590
• Publication Date: 2024-03-08T12:31:46Z
• Authors: Ratanaporn Poosathit; Patma Vityakon
• Keywords: Stoichiometry; Carbon fibers

Chemical quality of plant residues, which are the source dissolved organic C (DOC), determine molecular structure, notably functional group polysaccharides in DOC, and origins DOC-polysaccharide, transitioned from plant- to microbial-derived as decomposition progressed. The DOC-polysaccharides contribute soil (SOC) stabilization, but what factor associated with residue chemical regulates origin remains unknown. Balanced DOC N (DN) (DOC-and-DN) stoichiometry microbial substrates indicated by DOC-to-DN ratio enhances use efficiency (CUE). CUE indicates production compounds. We hypothesized that DOC-and-DN soils receiving residues was a key controlling DOC-polysaccharides. objectives this study were 1) during decomposition, 2) relationships metabolic quotient (qCO2 - inverse CUE), 3) qCO2 This employed data year 13 long-term field experiment on effect annual application varying processes sandy soils. During early stage (week 0-2), N-rich groundnut stover (GN) decreased, contrast low-N rice straw (RS), dipterocarp leaf litter (DP) medium-N tamarind leaf+petiole (TM). intermediate 2-8), GN RS had increasing ratios, opposed DP TM. Groundnut-treated lower average (6.8±2.6) than TM, (10.7±4.4, 12.1±5.4, 14.1±7.2, respectively). Positive influences three medium-to-low-N (R2 = 0.60** 0.74**) significant control CUE. qCO2, turn, influence (non-linear relationship) 0.30*).  In (high qCO2), it decreased (indicating increase CUE) corresponding decreases indicating these plant-derived. further beyond threshold 0.00026 mg CO2-C kg-1 biomass h-1 marked beginning (low an DOC-polysaccharides.  signified change their origin. Negative 0.36*) showed increased ratios caused Our results identified residues-treated prominent Imbalanced i.e., higher C-to-N brought about decrease later stage. Soil management via inputs requires careful consideration changes can affect SOC accumulation.