Soil erosion under simulated rainfall in relation to phenological stages of soybeans and tillage methods in Lages, SC, Brazil

Water erosion in surface soil conditions: runoff velocity, concentration and D50 index of sediments in runoff

“…This result is justified by greater RR kept over time, in the cropped treatments, compared to BHR ( Figure 1B). Greater roughness generated higher tortuosity over time in cropped and chiseled soils, slowing runoff flow, as reported by Engel et al (2009).…”

“…According to Roisin (2007), grass species increase water stability of soil aggregates compared to leguminous crops. The lower RR in BHR can be explained by the soil less resistance to breakdown (Martinez-Trinidad et al, 2012) and can be related to mechanical soil tillage and raindrop impact, increasing aggregate disruption in comparison with cropped treatments, as discussed by Engel et al (2009).…”

“…The velocity was measured in the six central meters of each plot, marked with stakes (6 m are located 2.5 m above and 2.5 m below the extremities). At the upper extremity, methylene blue dye (2 %) was applied and time required for it to run this distance was recorded, as described by Engel et al (2009).…”

“…Soil surface characteristics with greater influence on water erosion, related to runoff velocity and concentration and diameter of eroded sediments, are soil cover by crop residues and soil surface roughness (Cogo et al, 1984;Engel et al, 2009). These characteristics are usually found in conservative soil tillage (Bertol et al, 2003), represented by no-till and minimum tillage.…”

“…Crop residues can dissipate kinetic energy from raindrops and, in part, from runoff by slowing it down, hence, preventing soil disaggregation and sediment transport (Engel et al, 2009). Moreover, residues filter runoff, retaining coarse sediments and reducing sediment load.…”