Soil losses from typic cambisols and red latosol as related to three erosive rainfall patterns

Abstract

SUMMARYRainfall erosivity is one of the main factors related to water erosion in the tropics. This work focused on relating soil loss from a typic dystrophic Tb Haplic Cambisol (CXbd) and a typic dystrophic Red Latosol (LVdf) to different patterns of natural erosive rainfall. The experimental plots of approximately 26 m 2 (3 x 8.67 m) consisted of a CXbd area with a 0.15 m m -1 slope and a LVdf area with 0.12 m m -1 slope, both delimited by galvanized plates. Drainpipes were installed at the lower part of these plots to collect runoff, interconnected with a Geib or multislot divisor. To calculate erosivity (EI 30 ), rainfall data, recorded continuously at a weather station in Lavras, were used. The data of erosive rainfall events were measured (10 mm precipitation intervals, accuracy 0.2 mm, 24 h period, 20 min intervals), characterized as rainfall events with more than 10 mm precipitation, maximum intensity > 24 mm h -1 within 15 min, or kinetic energy > 3.6 MJ, which were used in this study to calculate the rainfall erosivity parameter, were classified according to the moment of peak precipitation intensity in advanced, intermediate and delayed patterns. Among the 139 erosive rainfall events with CXbd soil loss, 60 % were attributed to the advanced pattern, with a loss of 415.9 Mg ha -1 , and total losses of 776.0 Mg ha -1 . As for the LVdf, of the 93 erosive rainfall events with soil loss, 58 % were listed in the advanced pattern, with 37.8 Mg ha -1 soil loss and 50.9 Mg ha -1 of total soil loss. The greatest soil losses were observed in the advanced rain pattern, especially for the CXbd. From the Cambisol, the soil loss per rainfall event was greatest for the advanced pattern, being influenced by the low soil permeability.Index terms: rainfall erosivity, water erosion, kinetic energy, soil erodibility.( RESUMO: PERDAS DE SOLO EM CAMBISSOLO E LATOSSOLO VERMELHO, EM RELAÇÃO A TRÊS PADRÕES DE CHUVAS EROSIVAS

Water erosion associated with rainfall patterns in the extreme South of Bahia in eucalyptus post-planting

“…Therefore, the antecedent soil moisture was of great importance for the studies on rainfall pattern associated with soil and water losses, corroborating the study developed by Aquino et al (2013).…”

“…Rainfall erosivity is one of the most difficult factors to predict and control, and is defined as the potential of rainfall to cause erosion by the detachment and transport of soil particles. However, erosivity depends on basic physical characteristics, such as the size, shape and speed of raindrops when they reach the ground (AQUINO et al, 2013). and the occurrence of water erosion in this region hinder the conservationist planning of land use (OLIVEIRA et al, 2013b).…”

“…Thus, further studies under natural rainfall conditions are fundamental. Aquino et al (2013), seeking to relate soil losses with rainfall patterns in Haplic Cambisol and Red Latosol in the south of the state of Minas Gerais, observed higher soil losses by rainfall event associated with the advanced pattern. Similarly, Wang et al (2016), in a study carried out in Beijing, identified that the advanced pattern was related to 55 to 68% of soil losses.…”

Geomorphometric tool associated with soil types and properties spatial variability at watersheds under tropical conditions

“…At LCW, where DT predominates (92 % of the area), this soil class mostly occupies Slope, Hollow and Spur GUs. This watershed presents very steep slope gradients in the area, which tend to promote higher erosion rates and contribute to the weak development of its soils (Aquino et al, 2013). The ET and UT are predominantly located in Pit and Valley GUs, which are typical of lower elevation areas.…”

Erosividade das chuvas e tempo de recorrência para Lavras, Minas Gerais

“…Pode-se observar que os maiores valores de erosividade ocorrem de outubro a março e, no período de abril a setembro, são consideravelmente menores. Essa distribuição temporal é característica da região, com verão chuvoso e inverno seco, sendo que vários pesquisadores, em diversas regiões do país, têm encontrado situação semelhante (Dias & Silva, 2003;Silva et al, 2009;Bertoni & Lombardi Neto, 2010;Silva et al, 2010;Aquino et al, 2012;Aquino et al, 2013).…”