Significance of soil erosion on soil surface roughness decay after tillage operations

Soil surface roughness (SSR) indicates a soil's susceptibility to wind and water erosion and it is strongly related to field management practices. Several methods have been developed to capture and evaluate SSR under specific field and climate conditions. Based on previously developed techniques, the shadow analysis method has been shown to be a suitable technique for characterising SSR in the field when used in arid and semi-arid regions of Spain. This is because of the climate and soil conditions that prevail during the spring and summer in the semiarid regions of Spain. However, the method has not yet been used in whole climate and edaphic conditions and still needs further development.Therefore, the goal of this study was to assess the SSR decay of a sandy clay loam soil after fall tillage operations using the shadow analysis method. The experiment was performed in the field in eight controlled 1 m2 plots of a Technosol (FAO, 2006). The project was designed to evaluate the validity of the method for further measuring SSR decay and to overcome potential problems associated with the method.The data were collected from the beginning of the fall of 2009, after tillage operations, through the spring of 2010, when the fields were tilled again. Half of the experimental plots were covered and used as controls. The remainder of the plots was uncovered to evaluate SSR decay mainly associated with water erosion. The average SSR was similar for the two subsets at the beginning of the experiment with 68% and 70%, respectively. The SSR after the experimental trial showed marked differences between the covered (45%) and uncovered plots (20%) after 53.2 mm of rainfall. The parameters demonstrated that the method can be used to study the influence of wind and water erosion on SSR decay at field conditions throughout the year. The shadow analysis technique has the advantages of being non-disturbing, easy to handle and less time consuming than other classical techniques. However, the method presents some limitations and further research must be conducted to adjust for utilisation in the field.

► We evaluated the SSR decay at field after fall tillage operations.
► Shadow analysis method at field conditions was tested during the whole year.
► The main processes of erosion were due to rainfall.
► Shadow analysis method has some limitations when used in fall and winter.