Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom, 73170, Thailand.
Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom, 73170, Thailand.
J Environ Manage. 2022 Jan 15;302(Pt A):113978. doi: 10.1016/j.jenvman.2021.113978. Epub 2021 Oct 25.
Fire has been used for land clearing under rotational shifting cultivation (RSC) in Northern Thailand for a long time. However, the effects of fire on soil organic carbon (SOC), soil total nitrogen (STN), and soil properties are not well understood. We determined SOC, STN, and soil properties of the topsoil layer (0-30 cm) along a fallow chronosequence under RSC and assessed how fire affects SOC, STN, and soil properties. Eight fields at Ban Mae Pok, Mae Chaem District, Chiang Mai Province, Northern Thailand, were investigated. The levels of SOC, STN, and soil properties were observed at three time points: pre-burning, post-burning (5 minutes after burning), and post-harvest (nine months after burning). The highest SOC and STN stocks, organic matter (OM), and clay content were observed for the longest fallow period (7 years fallow), whereas the shortest period (1 year fallow) resulted in the lowest SOC and STN stocks. Fire caused no significant changes in SOC, STN, and some soil properties (soil texture, available P, exchangeable K, exchangeable Ca, exchangeable Mg, bulk density, and OM) because of the low fire intensity and short fire duration. Only pH and electrical conductivity were significantly increased (p ≤ 0.05) after burning due to the demobilization of base cations in burnt vegetation and incorporation into the soil with ashes and wood charcoal. Although fire may still be necessary for RSC, maintaining the fire intensity below 380 °C to reduce SOC losses and appropriate post-fire management strategies to reduce STN losses are crucial.
在泰国北部，轮作迁移农业（RSC）长期以来一直使用火烧来清理土地。然而，火烧对土壤有机碳（SOC）、土壤全氮（STN）和土壤性质的影响还不太清楚。我们在 RSC 下沿着休耕时间序列确定了表土层（0-30cm）的 SOC、STN 和土壤性质，并评估了火烧对 SOC、STN 和土壤性质的影响。在泰国北部清迈府湄昌区班美波克调查了 8 个地块。在三个时间点观察了 SOC、STN 和土壤性质的水平：燃烧前、燃烧后（燃烧后 5 分钟）和收获后（燃烧后九个月）。最长休耕期（7 年休耕）的 SOC 和 STN 储量、有机质（OM）和粘粒含量最高，而最短休耕期（1 年休耕）的 SOC 和 STN 储量最低。由于低火强度和短火持续时间，火烧对 SOC、STN 和一些土壤性质（土壤质地、有效磷、可交换钾、可交换钙、可交换镁、容重和 OM）没有造成显著变化。仅由于燃烧植被中的碱基阳离子解吸并与灰烬和木炭一起掺入土壤，pH 值和电导率在燃烧后显著增加（p≤0.05）。尽管火烧对 RSC 仍然是必要的，但将火强度控制在 380°C 以下以减少 SOC 损失和采取适当的火灾后管理策略以减少 STN 损失至关重要。
