Work

Impact of different soil erosion levels on gross N transformation processes and gaseous N losses: An incubation study

Year: 2025

Type: article

Abstract: Erosion is a key driver of topsoil removal in agriculture, resulting in nutrient losses and leaving truncated soil profiles on shoulder slopes, where subsoil material can be incorporated into topsoil by the plough, changing soil properties and, thus, altering biogeochemical cycling and associated nitrogen (N) losses. To date, the effects of topsoil erosion on N cycling have rarely been investigated. We conducted a short-term mesocosm experiment, integrating 15 N tracing techniques to quantify N transformation processes, focusing on N availability and N losses in three artificially eroded agricultural topsoils. Nitrogen transformation pathways were simulated using the numerical model Ntrace , considering N uptake by maize ( Zea mays L.) at early development stages. The 15 N label also allows the quantification of nitrous oxide (N 2 O) and dinitrogen (N 2 ) losses by applying the 15 N gas flux method ( 15 NGF). Topsoil erosion significantly reduced gross N turnover and consequently N 2 O and N 2 emissions in both treatments with and without plants. The oxidation of ammonium (NH 4 + ) to nitrate (NO 3 - ) was by far the dominating N pathway across all investigated topsoils, followed by N org mineralization > NH 4 + immobilization. However, more than 90% of total N 2 O losses derived from the NO 3 - pool, with coupled nitrification-denitrification assumed to be the dominant process at water contents of ∼40 % WFPS. Although maize more than doubled N 2 O+N 2 emissions in some treatments, the overall effect of topsoil dilution on gaseous N losses was considerably greater, independent of maize presence. Our study contributes to a more comprehensive understanding of N cycling in erosion-affected agricultural soils, which is essential for enhancing N fertilizer use efficiencies and reducing N pollution.

Source: Soil Biology and Biochemistry

DOI: 10.1016/j.soilbio.2025.109905

Authors: Julia Schoof, Maire Holz, Tobias Rütting, Reinhard Well, Caroline Buchen-Tschiskale

Institutions: Humboldt-Universität zu Berlin, Johann Heinrich von Thünen-Institut, Leibniz Centre for Agricultural Landscape Research, University of Gothenburg

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Life on land, Zero hunger, Climate action

Open Access status: hybrid

Estimated APC paid: $4,950