Evaluating erosion in an Inceptisol (soil) in Tunja (Boyacá department, Colombia) having different coverage regarding the impact of simulated rainfall

Abstract

The area surrounding the city of Tunja in the Boyacá department has a heterogeneous climate and adverse conditions facilitating erosion. Scarce vegetation cover does little to reduce the impact of the rain and increases run-off. This study was aimed at analy- sing different types of rainfall coverage, intensity and duration by simulation. A experimental 3x3 Latin square design was used, with 3 rainfall intensities (10, 20 and 30 mm*h-1), 3 rainfall durations (1, 2 and 3 hours) and 3 types of soil coverage (kikuyo, na- tural coverage, bare). Each Latin square had 3 repetitions, giving a total of 27 experimental units. Significant differences were found between rainfall intensities evaluated; 30 mm*h-1 rainfall intensity generated 2,218.6 kg*ha-1 of soil loss caused by run-off. Kikuyo coverage was the vegetal cover presenting the least soil loss and greatest infiltration (1,019.1 kg*ha-1 soil loss by run-off and 0.88 cm accumulated infiltration). Rainfall duration did not affect soil loss due to run-off and infiltration. Tunja's annual rain- fall pattern showed that 2006 presented the greatest soil loss (46,663 kg*ha-1 for bare soil). This meant that corrective action must be taken quickly by implementing vegetal cover to mitigate the effects of rainfall on exposed soil to reduce the loss of such valuable resource.