Soil Erosion Laboratory, Department of Geography, Universidade Estadual do Centro-Oeste, UNICENTRO, Street Simeão Camargo Varela de Sá, 03 Mailbox, 3010, 85040-080 Guarapuava, Paraná, Brazil.
Sci Total Environ. 2021 Apr 10;764:142823. doi: 10.1016/j.scitotenv.2020.142823. Epub 2020 Oct 7.
Several studies have demonstrated the effects of slash-and-burn agriculture on soil chemical properties immediately or short-term after burning. This study aims to answer if: a) the slash-and-burn system affects soil chemical properties; b) management effects remain in a fallow chronosequence; and if c) these effects are restricted to the soil surface. The study was developed in the south-eastern region of the state of Paraná, located in southern Brazil. On-site, the land preparation was made through procedures comprising of fire, cropping, and fallow. The methodology was based on the chronosequence approach by different fallow periods: native forest, 30 days after burning, 2-year fallow, 5-year fallow, 7-year fallow, and 12-year fallow. The soil samples were collected at 0-5 and 5-10 cm depths for chemical analysis (pH, organic matter, ions availability (extractable phosphorus, potassium, calcium, magnesium and aluminum) and cation exchange capacity). The results indicate significant changes at 0-5 cm depth. The soil organic matter levels remained constant throughout the chronosequence. The direct effects of burning led to increased pH and nutrient availability (extractable phosphorus and calcium), which decreased within 2 to 5 years of fallow. The increase in basic cations was sufficient to guarantee the soil nutrient status up to 7 years of fallow. Successive slash-and-burn cycles in the same area caused an increase in soil sand content, and reduced cation exchange capacity.
几项研究已经证明，刀耕火种农业对燃烧后立即或短期的土壤化学性质有影响。本研究旨在回答以下问题：a）刀耕火种系统是否会影响土壤化学性质；b）管理效果是否会在休耕序列中持续存在；以及 c）这些影响是否仅限于土壤表面。该研究在巴西南部巴拉那州东南部进行。在现场，通过包括火耕、种植和休耕在内的程序进行土地准备。该方法基于不同休耕期的年代序列方法：原始森林、燃烧后 30 天、2 年休耕、5 年休耕、7 年休耕和 12 年休耕。在 0-5 和 5-10 cm 深度采集土壤样本进行化学分析（pH 值、有机质、离子有效性（可提取磷、钾、钙、镁和铝）和阳离子交换容量）。结果表明，在 0-5 cm 深度有显著变化。整个休耕序列中，土壤有机质水平保持不变。燃烧的直接影响导致 pH 值和养分有效性（可提取磷和钙）增加，但在休耕 2 至 5 年内减少。基础阳离子的增加足以保证土壤养分状况长达 7 年的休耕。在同一地区连续进行刀耕火种循环会导致土壤砂含量增加，阳离子交换能力降低。
