Relations between roughness indices: results of two years of experiences

[Abstract] Tillage-induced soil surface roughness is an important factor in preventing runoff generation and soil erosion, because of depressions storing water and the effect of surface shape protecting soil from splash and detachment. Microrelief characterization is made by means of roughness indices calculated from surface heights collected with pinmeters or with the more accurate optical rugosimeters. When analyzing surface roughness, the selection of a measurable parameter describing rough-ness is critical. As a continuation of a previous work, 157 microrelief measurements have been made, under a wide range of tillage and soil surface evolution conditions. Study period was from April, 1998 to October, 1998. Four roughness indices were calculated after trend removal, including random roughness, limiting difference, limiting slope, and tortuosity. Relation between roughness indices has been studied. Like in previous work, limiting difference and random roughness showed a strong correlation, due to their similar meaning. A good correlation was also found between tortuosity and limiting slope