ABSTRACT

In agricultural systems, soil carbon dioxide emissions and physical properties are thought to depend largely on management practices. This field study was carried out in a semi-arid region of eastern Tunisia to evaluate the effects of tillage management on soil carbon dioxide emissions and related physical properties; bulk density (BD), penetration resistance (PR), total porosity (TP) and air-filled porosity (AFP). Tillage management treatments included plowing with a moldboard plow or a disk plow to different depths, described here as shallow (10 cm), medium (15 cm) and deep (25 cm). No-tillage was also considered as a control plot. Correlation analysis was used to explore how soil carbon dioxide emissions (CO₂) were related to the other studied properties. The results showed higher carbon dioxide (CO₂) emissions (p < .05) from tilled soil compared to no-till (NT), regardless of the tillage management. No significant differences in carbon dioxide (CO₂) emissions were found between moldboard and disk plow tillage at the same tillage depth. Soil carbon dioxide release was the highest after deep tillage (moldboard = 0.101 t ha⁻¹ and disk plow = 0.107 t ha⁻¹) suggesting that deeper tillage to 25 cm promoted higher carbon dioxide (CO₂) emissions. Significant differences with tillage were observed in bulk density (BD) and penetration resistance (PR) compared to no-tillage. Correlations of carbon dioxide emissions to soil physical properties across all the tillage treatments indicated significant negative relationships between carbon dioxide (CO₂) emissions and soil bulk density (BD) and penetration resistance (PR) and significant positive relationships between carbon dioxide (CO₂) and total porosity (TP) and air-filled porosity (WFP) suggesting that these soil attributes are important controlling factors of carbon dioxide (CO₂) emissions.

摘要

在农业系统中，土壤二氧化碳排放量和物理特性被认为在很大程度上取决于管理实践。这项实地研究在突尼斯东部的半干旱地区进行，以评估耕作管理对土壤二氧化碳排放和相关物理特性的影响；体积密度 (BD)、抗渗透性 (PR)、总孔隙率 (TP) 和充气孔隙率 (AFP)。耕作管理处理包括用犁板犁或圆盘犁耕作不同深度，这里描述为浅（10 厘米）、中（15 厘米）和深（25 厘米）。免耕也被视为控制小区。相关分析用于探索土壤二氧化碳排放 (CO ₂ ) 如何与其他研究特性相关。结果显示较高的二氧化碳 (CO₂ )与免耕 (NT) 相比，耕作土壤的排放量 ( p < .05)，无论耕作管理如何。在相同耕作深度下，犁耕和圆盘犁耕作的二氧化碳 (CO ₂ ) 排放没有显着差异。深耕后土壤二氧化碳释放量最高（犁板 = 0.101 t ha ^-1和圆盘犁 = 0.107 t ha ^-1）表明深耕至 25 cm 促进了更高的二氧化碳（CO ₂) 排放。与免耕相比，耕作在堆积密度 (BD) 和穿透阻力 (PR) 方面观察到了显着差异。所有耕作处理中二氧化碳排放量与土壤物理特性的相关性表明，二氧化碳 (CO ₂ ) 排放量与土壤容重 (BD) 和渗透阻力 (PR) 之间存在显着负相关关系，而二氧化碳 (CO ₂ )之间存在显着正相关关系总孔隙度 (TP) 和充气孔隙度 (WFP) 表明这些土壤属性是二氧化碳 (CO ₂ ) 排放的重要控制因素。