High-resolution monitoring of diffuse (sheet or interrill) erosion using structure-from-motion

Cândido, B.M. and Quinton, J.N. and James, M.R. and Silva, M.L.N. and de Carvalho, T.S. and de Lima, W. and Beniaich, A. and Eltner, A. (2020) High-resolution monitoring of diffuse (sheet or interrill) erosion using structure-from-motion. Geoderma, 375. ISSN 0016-7061

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Abstract

Sheet erosion is common on agricultural lands, and understanding the dynamics of the erosive process as well as the quantification of soil loss is important for both soil scientists and managers. However, measuring rates of soil loss from sheet erosion has proved difficult due to requiring the detection of relatively small surface changes over extended areas. Consequently, such measurements have relied on the use of erosion plots, which have limited spatial coverage and have high operating costs. For measuring the larger erosion rates characteristic of rill and gully erosion, structure-from-motion (SfM) photogrammetry has been demonstrated to be a valuable tool. Here, we demonstrate the first direct validation of UAV-SfM measurements of sheet erosion using sediment collection data collected from erosion plots. Three erosion plots (12 m × 4 m) located at Lavras, Brazil, with bare soil exposed to natural rainfall from which event sediment and runoff was monitored, were mapped during two hydrological years (2016 and 2017), using a UAV equipped with a RGB camera. DEMs of difference (DoD) were calculated to detect spatial changes in the soil surface topography over time and to quantify the volumes of sediments lost or gained. Precision maps were generated to enable precision estimates for both DEMs to be propagated into the DoD as spatially variable vertical uncertainties. The point clouds generated from SfM gave mean errors of ~2.4 mm horizontally (xy) and ~1.9 mm vertically (z) on control and independent check points, and the level of detection (LoD) along the plots ranged from 1.4 mm to 7.4 mm. The soil loss values obtained by SfM were significantly (p < 0.001) correlated (r 2 = 95.55%) with those derived from the sediment collection. These results open up the possibility to use SfM for erosion studies where channelized erosion is not the principal mechanism, offering a cost-effective method for gaining new insights into sheet, and interrill, erosion processes.

Item Type:
Journal Article
Journal or Publication Title:
Geoderma
Additional Information:
This is the author’s version of a work that was accepted for publication in Geoderma. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Geoderma, 375, 2020 DOI: 10.1016/j.geoderma.2020.114477
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1100/1111
Subjects:
ID Code:
144644
Deposited By:
Deposited On:
13 Jul 2020 15:25
Refereed?:
Yes
Published?:
Published
Last Modified:
01 Oct 2020 03:48