Measurement of runoff and soil loss from two differently sized plots in a subtropical environment (Brazil)

Abstract

Studies of soil erosion on small plots present upscaling problems. The results in the literature on the effect of slope length (i.e. scale) on runoff and soil erosion are contradictory. Furthermore, most studies that examine scale effects measured through erosion plots have been conducted in Mediterranean environments. The objective of this study was to assess the effects of plot size on runoff and soil loss in a subtropical environment. Other measurements were taken to appraise the topsoil property changes inside the plots. The soil was ploughed twice, the surface was leveled with a hoe and it was kept bare during the experiment. Data were collected from 10 paired plots, five plots measuring 10 m × 1 m and five plots measuring 1 m × 1 m, installed in the same pedo‐geomorphologic unit. Measurements were carried out from November 2008 to November 2009. During this period, 97 natural storms were registered. The results indicate that the small plots tended to have higher runoff (30% higher) compared to larger plots, especially during periods of greater rainfall volume, duration and intensity. The soil loss was similar in both the 1 m2 plots (6·33 kg/m2) and the 10 m2 plots (6·26 kg/m2). Moreover, the dynamics of the soil loss during the experiment was relatively similar across both plot sizes. The large plots tended to have a greater internal complexity. In these plots, the steps retreat were higher, the overland flow scars were more frequent, and points of rill initiation and protochannels emerged in several parts of the plots. The results of the small plots were comparable to the results obtained on the large plots, especially in relation to soil loss. These plots were useful for short‐term assessments of soil erosion. Copyright © 2011 John Wiley & Sons, Ltd.

Patterns Over a 24-Year Period Show an Increase in Native Vegetation Cover and Decreased Fragmentation in Andean Temperate Landscapes, Chile

“…In Brazil, Thomaz and Vestena (2012) found that increasing plot size reduces runoff results because the surface is more complex, while soil erosion values are comparable; they note that 100 m 2 erosion plots are acceptable as a representative area (Hudson, 1997).…”

Rill erosion on an oxisol influenced by a thin compacted layer

“…In most run-on experiments, no explanations were given for the use of certain flow rates. In a previous study by Thomaz & Vestena (2012), the authors showed that during one year, even after high-intensity and long-duration rainfalls, no rill was formed in the Oxisol. Therefore, a reasonable amount of extra flow was used to produce the effect of rill development.…”

“…To make the rainfall simulation more realistic, a total of 71 natural rains in a typical year (1920 mm) in the subtropical region of Guarapuava were analyzed for volume (mm), intensity (mm h), and duration (h or min) (Thomaz & Vestena, 2012).…”

“…The control of soil erosion by water must take the hillslope and soil characteristics into account, and scales which are related to flow pathways in agricultural systems (Auzet et al, 2002;Stroosnijder, 2005;Boix-Fayos et al, 2006;Thomaz & Vestena, 2012).…”

Dinâmica Do Carbono Orgânico E Processos Hidrológicos Na Escala Da Bacia Hidrográfica: Uma Revisão

“…Os processos erosivos atuam como principais agentes no transporte e deposição superfi cial do carbono orgânico na paisagem (Starr et al, 2006;Ritchie et al, 2007;Schwanghart & Jarmer, 2011), promovendo ainda a remoção seletiva dos agregados do solo (Thomaz & Vestena, 2012). Considerando a desagregação primária de partículas mais fi nas (diâmetros reduzidos) e mais leves (de menor densidade) (Lal, 1995), os sedimentos são usualmente enriquecidos não apenas com as partículas de silte e argila transportadas em conjunto com as formas estáveis de carbono orgânico presentes no solo (Baldock & Skjemstad, 2000), mas também de matéria orgânica particulada de fácil decomposição (Chaplot et al, 2005).…”