Relative spatial differences in sediment transport in fire-affected agricultural landscapes: A field study

• Published in: Aeolian research Vol. 39; pp. 13 - 22
• Main Authors: Jeanneau, Amelie C., Ostendorf, Bertram, Herrmann, Tim
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2019
• Subjects: Aeolian transport; Fire; Sediment transport; Soil security; Spatial variability; Wind erosion; Spatial variability; Soil security; Aeolian transport; Wind erosion; Fire; Sediment transport
• ISSN: 1875-9637; 2212-1684
• DOI: 10.1016/j.aeolia.2019.04.002

[Display omitted] •Wind erosion following fires in dryland agriculture is little understood.•Sediment transport is high and spatially variable on burnt and bare patches.•Measuring field-scale sediment transport complements wind tunnel experimental studies.•Unburnt wheat stubble can reduce sediment transport on nearby burnt patches.•Findings will lead to improved management of dryland agriculture. Fires can considerably increase wind erosion risk in dryland agricultural regions. While wind erosion post-fire has been extensively studied in rangeland and grazing landscapes, limited work has considered post-fire erosion on annual plant communities and annual crops. Here we evaluated the relative spatial differences in patterns of sediment transport between burnt and unburnt crop stubble sites. Following a severe wildfire, we studied the spatio-temporal pattern of aeolian sediment transport with an array of Modified Wilson and Cooke (MWAC) dust samplers on adjacent burnt and unburnt wheat stubble. Sediment collection was conducted during nine weeks over an area of 3 ha. Collection rates were converted to horizontal sediment flux to derive spatial distribution maps and perform statistical analysis. Compared to the unburnt plot, we observed that sediment transport was up to 1000 times higher within the burnt area. This could lead to damages to emerging annual crops sown after the fire if no management strategy was applied. There was only negligible sediment flux in areas with shallow and low-density stubble, which gradually increased with distance from the unburnt area. These results suggest that strips of remaining unburnt stubble could provide a potential benefit to adjacent burnt or bare plots. Patterns of sediment transport were consistent in all sampling periods and were observed at a spatial scale undetectable in wind tunnel studies, indicating that field observations could complement fine-scale experimental studies to assess environmental processes in real-life conditions.