Effects of amorphous silica on CO2 and N2O emissions mediated by water-filled pore space in diverse agricultural soils
Year: 2026
Type: article
Abstract: Silicon (Si) is abundant in the Earth’s crust; however, its amorphous form (ASi) is often depleted in agricultural soils. While ASi benefits plant nutrient uptake and growth, its effects on soil pore characteristics, such as water-filled pore space (WFPS), and regulating greenhouse gas (GHG) emissions remain poorly understood. We investigated the effect of ASi addition on soil bulk density, WFPS, and subsequent N2O and CO2 emission dynamics in two soil types of differing texture: Luvisols (moderate silt and clay) and Arenosols (low silt and clay). In a first experiment, we assessed how varying ASi levels affected soil bulk density and WFPS. A second experiment investigated the impact of 1% ASi on N2O and CO2 emissions. ASi addition altered soil bulk density, leading to a decrease in WFPS, especially at 10% ASi in Luvisols. In Arenosols, WFPS increased at 1% ASi before declining at higher rates. The 1% ASi addition increased CO2 and N2O emissions in Luvisols but reduced both in Arenosols. These contrasting outcomes likely reflect a dual effect of ASi: in finer-textured Luvisols, ASi reduces bulk density and increases pore volume, which lowers WFPS under fixed water input, improves aeration, and enhances microbial respiration and nitrification, resulting in increased CO2 and N2O emissions. In coarser-textured Arenosols, ASi may reduce macroporosity by clogging larger pores, resulting in higher WFPS and oxygen limitation, thereby decreasing emissions. Our findings suggest ASi has texture-dependent effects on soil properties and GHG emissions. These outcomes highlight the need for further field-based investigation under natural conditions.
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7133553463