A linear photogrammetric method for measuring erosion in agricultural fields

Erosion is defined as the displacement of solid particles originating from soil, rock, and sediments by forces of wind, water, and ice. Erosion affects soil microtopography and surface roughness, leading to clogging of surface drainage systems, flooding, and destruction of the upper part of the soil structure cross-section, and cause damages to cultivated land. Therefore, monitoring changes in the amount and rate of soil erosion is important for agricultural planning as well as for planning the use of different soil conservation systems. This article describes a scheme combining terrestrial photogrammetry and image analysis for measuring erosion amounts and estimating the change in volume of raised beds resulting from irrigation or rainstorms in cultivated fields. The method was validated on ridged and furrowed potato fields on sandy and loam soils (Typic Rhodoxeralfs) in the coastal plain of Israel. Unlike existing methods that are labor intensive and error prone, the approach described here enables a high-level of automation and accuracy while making use of low-cost digital cameras. Emphasis is placed on parameters for robustness of the model and on linear methods that do not require approximate parameters for the photogrammetric solution, thus enabling the use of consumer cameras. Experiments show that accurate results can be achieved in estimating volume and erosion. The accuracy of the measurements is of 0.007 m ³ per 1000 m2.