Dynamics of 13C and 15N isotopes in fire-affected soils under rotational shifting cultivation in Northern Thailand

作者：Noppol Arunrat, Sukanya Sereenonchai, Hajime SAKURADA, Praeploy Kongsurakan, Yo Toma, Ryusuke Hatano · 发表于：Biogeochemistry · 年份：2026 · DOI：10.1007/s10533-026-01305-3 · 被引用次数：6 · 研究领域：Fire effects on ecosystems、Soil Carbon and Nitrogen Dynamics、Ecology and Vegetation Dynamics Studies

Understanding the biogeochemical consequences of fire and land-use history in tropical upland systems is essential for sustainable soil management. We investigated the vertical distribution of stable carbon (δ 13 C) and nitrogen (δ 15 N) isotopes in soils under rotational shifting cultivation (RSC) in Northern Thailand. Three fields with distinct land-use histories were analyzed: a continuously fallow site for seven years (CF-7Y), a six-year fallow RSC site (RSC-6Y), and a twelve-year fallow RSC site (RSC-12Y). The RSC-6Y and RSC-12Y fields were left fallow for 6 and 12 years, respectively, with both fields burned in 2022 and entered a new two-year fallow phase. By contrast, CF-7Y field was last burned in 2017 and has remained under continuous fallow since that time. In 2024, soil samples were collected from upper, middle, and lower slope positions to analyze total organic carbon (TOC), total nitrogen (TN), TOC:TN, and δ 13 C and δ 15 N signatures across the 0–100 cm soil profile. Results revealed that longer fallow periods (RSC-12Y) enhanced vertical movement and stabilization of TOC and TN, with more enriched δ 13 C and δ 15 N values at depth—indicative of legacy fire effects and microbial transformation. The CF-7Y field showed high surface TOC and more negative δ 13 C values, reflecting active C₃ vegetation inputs and minimal decomposition. The δ 13 C values were significantly affected by both site and slope position, suggesting independent influences of land-use history a...