Dataset for: Rice cultivation in reclaimed saline-alkali soils reshapes DOM transformation pathways and compromises groundwater carbon stability

Dataset Description This dataset supports the study entitled “Rice cultivation in reclaimed saline-alkali soils reshapes DOM transformation pathways and compromises groundwater carbon stability”. It contains the processed molecular transformation, carbon metabolic pathway, and metagenomic datasets used to investigate the effects of saline–alkali land reclamation on DOM transformation and carbon cycling across the soil–vadose zone–groundwater continuum. The dataset consists of three main components: 1. PMDThis folder contains the paired mass distance (PMD) calculation results for each sampling site based on FT-ICR-MS analysis. PMD data were used to reconstruct DOM molecular transformation networks and identify dominant transformation pathways, reaction frequencies, and molecular reactivity patterns across different depths (surface soil, vadose zone, and groundwater) before and after reclamation. 2. PATHs1_5This folder contains reaction datasets corresponding to five representative carbon metabolic pathways derived from the KEGG database, including: Glycolysis (M00001) Calvin cycle (M00165) Arnon–Buchanan cycle (M00173) Wood–Ljungdahl pathway (M00377) Methanogenesis (M00563) These pathway datasets were used to identify potential molecular transformation pairs associated with carbon degradation, carbon fixation, and methane production, and to quantify their variation along the vertical soil–groundwater profile. 3. R_microThis folder contains microbial taxonomic relative abundance data and functional gene relative abundance data obtained from metagenomic sequencing. Taxonomic annotations and KEGG module assignments were integrated to identify functional microorganisms involved in DOM degradation, carbon fixation, and methanogenesis across saline–alkali soils, reclaimed paddy soils, and groundwater. Sampling Information Samples were collected from a reclaimed saline–alkali paddy field and an adjacent untreated saline–alkali bare land in Songyuan. Sampling depths included 20 cm, 40 cm, 120 cm, 180 cm, and groundwater. Data Usage These datasets can be used for: Reconstruction of DOM molecular transformation networks Identification of depth-dependent carbon transformation pathways Linking DOM molecular reactivity with microbial functional potential Evaluating the impacts of land reclamation on groundwater carbon stability Detailed experimental procedures, filtering criteria, and analytical workflows are described in the associated manuscript and Supporting Information.