Plantas de cobertura no controle das perdas de solo, água e nutrientes por erosão hídrica

Abstract

R ESU M OPlantas com alto índice de cobertura e elevada produtividade de fitomassa propiciam melhor proteção ao solo, amortecendo o impacto das gotas de chuva sobre a superfície do solo reduzindo, consequentemente, os processos erosivos. Objetivou-se avaliar a influência das plantas de cobertura e dos espaçamentos de plantio no controle das perdas de solo, água e nutrientes por erosão hídrica, visando à conservação do solo. O experimento foi conduzido em um Argissolo Vermelho-Amarelo, cujos tratamentos foram definidos por três espécies de plantas de cobertura: crotalária júncea, feijão-deporco e milheto e com dois espaçamentos entrelinhas (0,25 e 0,50 m). Para a quantificação das perdas de solo, água e nutrientes, utilizaram-se parcelas de 4 x 12 m em que a maior dimensão obedeceu ao sentido do declive. Nos meses de dezembro e janeiro ocorrem os maiores valores de erosividade requerendo, neste período, melhor cobertura da superfície do solo. O feijão-de-porco foi a espécie que apresentou maior potencial no controle dos processos erosivos; quanto ao espaçamento a melhor proteção do solo para todas as culturas foi obtida no espaçamento de 0,25 m, propiciando menores perdas de solo, água e nutrientes. Palavras-chave: crotalária júncea, feijão-de-porco e milhetoCover crops to control soil, water and nutrient losses by water erosion A B ST R A C T Cover plants with high coverage index and biomass productivity provide a better soil protection, cushioning the impact of the raindrops on the soil surface, thus reducing the erosion process. The objective of this study was to evaluate the influence of cover crops and plant spacing in the control of soil, water and nutrient of this study losses by water erosion, aiming the soil conservation. The experiment was conducted in the Red-Yellow Argisol, with three treatments of cover crops; sunn hemp, jackbean and millet, in two row spacing (0.25 and 0.50 m). To quantify the loss of soil, water and nutrients, plots of 4 x 12 m were used, and the larger dimension followed up and down slope. During the months of December and January there were the highest erosivity values, requiring in this period a better coverage of the soil surface. The jackbean was the species with the highest potential in the erosion control; and the spacing that promoted the best soil protection for all crops was 0.25 m, providing lesser losses of soil, water and nutrients.

Soil cover plants on water erosion control in the South of Minas Gerais

“…Millet showed the least effectiveness for the control of water erosion, regardless of the tillage method. Similar results were determined by Cardoso et al (2012), where the jack bean was the plant with the greatest performance on the control of the erosive process. The sediments drag potential (SDP) varied from 0.0849 Mg ha -1 mm -1 on the control plot to 0.0255 Mg ha -1 mm -1 on the jack bean under contour seeding plot ( Figure 2).…”

“…Silva et al (2005), Silva et al (2010), Castro et al (2011), andCardoso et al (2012) also registered high rainfall erosive potentials during the period of November thru March in the Minas Gerais state.…”

“…The jack bean presented faster initial growth than the other cover plants, aspect observed at 29 and 41 days after sowing (DAS) and the highest average plant cover index values. According to Cardoso et al (2012), jack bean has a faster growth habit and alternate leaves with large elliptical-oval leaflets interspersed between themselves, which makes this species able to provide high vegetation coverage and greater potential to control the erosive process. Therefore, after soil preparation, the higher the speed a plant covers the soil, the more effective this plant will be at controlling erosion.…”

“…Erosion starts with the raindrop impact on the soil's surface, causing the breakdown of aggregates and subsequently the climate, soil, topography, vegetation, land use, and soil conservation and management practices (PIRES et al, 2006). Thus, in places where the rainfall erosivity is high and the soil surface presents sparse vegetation, large losses of soil, water, nutrients, and carbon may occur (CARDOSO et al, 2012).…”

Clay and Phosphorus Losses by Erosion in Oxisol With Sugarcane Residues

“…The presence of live or dead plant cover on the soil surface intercepts the raindrops impact on the ground, protecting it (CARDOSO et al, 2012).Consequently, there is the reduction of the surface sealing formation and soil disaggregation, preserving the physical properties of the soil, reducing erosion (PANACHUKI et al, 2011 evaluated the soil losses, nutrients and organic matter in the eroded sediment, in the absence and presence of vegetation cover by sugarcane residues and observed that soil losses and organic matter, as the concentration of nutrients in the sediment, were lower in plots with 50% or more coverage with sugarcane straw.…”