Erosão hídrica em diferentes sistemas de cultivo e níveis de cobertura do solo

Abstract

Resumo -O objetivo deste trabalho foi avaliar, sob chuva simulada, o efeito da cobertura vegetal sobre a erosão de um Argissolo Vermelho, no Estado de Mato Grosso do Sul, nos seguintes sistemas de cultivo: soja, com preparo convencional; soja, em plantio direto; pastagem estabelecida, sem pisoteio animal; e condição de solo exposto, como padrão de comparação. A cada 20 dias, foram tiradas fotografias digitais para a estimativa da cobertura do solo, e chuvas simuladas de 60 mm h -1 foram aplicadas às parcelas experimentais, com uso do simulador portátil de chuvas. As perdas de solo, quantificadas a cada 2 min, variaram de 3,10 a 11,40 Mg ha , no cultivo de soja sob plantio direto. As perdas de solo diminuíram com o aumento da cobertura vegetal. Na pastagem, a máxima cobertura foi de 98,10%. Os efeitos benéficos do preparo convencional são temporários, o que torna o solo mais suscetível à erosão do que os sistemas conservacionistas.Termos para indexação: Glycine max, Urochloa ruziziensis, perda de solo e água, chuva simulada. Hydraulic erosion in different tillage systems and soil coverAbstract -The objective of this work was to evaluate, under simulated rainfall, the effect of soil cover on the erosion of a Typic Hapludalf erosion, in the state of Mato Grosso do Sul, Brazil, in the following crop systems: soybean, under conventional tillage; soybean, under no-tillage; established pasture, without cattle trampling; and exposed soil, as a comparison standard. Digital photographs were taken every 20 days for soil cover estimate, and 60 mm h -1 simulated rainfall was applied on the experimental plots, using a portable sprinkler infiltrometer. Soil losses, quantified every 2 min, ranged from 3.10 to 11.40 Mg ha -1 , in exposed soil, and from 0.03 to 0.19 Mg ha -1 , in established pasture; water losses ranged from 300 to 555 m 3 ha -1 , in exposed soil, and from 63 to 229 m 3 ha -1 , in soybean cultivation under no-tillage. Soil losses decreased with the increase in vegetation cover. In the pasture, the maximum vegetation cover was 98.10%. Conventional tillage has temporary positive effects, which makes the soil more susceptible to erosion than the conservationist systems.

Relationship between remote sensing data and field-observed interril erosion

“…Twenty-four hours before each test, and with the objective to show more favorable conditions to the occurrence of surface runoff, the plots received a pre-wetting, unifying the humidity conditions before the simulated rainfall application (Almeida et al, 2016). This procedure was performed by adding water gently and homogeneously in the plot, through a watering can, until the occurrence of runoff.…”

Efeito residual de diferentes coberturas em cultivares de alface / Residual effect of different toppings on lettuce cultivars

“…A produção dessas cultivares pode apresentar resultados promissores, dependendo do manejo dado a cultura. Entre as formas de manejo da alface, a cobertura do solo, pode ser escolhida como uma aliada apresentando diversos benefícios, tais como: Controle da erosão hídrica e baixa desagregação do solo (ALMEIDA et al, 2016), prospecção de melhorias no solo a níveis físicos, químicos e biológicos, promovendo um ótimo desenvolvimento de raízes, além de ocasionar a diminuição da incidência de plantas invasoras e consequentemente, diminuindo o custo com mão-de-obra (FAVARATO et al, 2017).…”

Corn Cropping System And Nitrogen Fertilizers Technologies Affect Ammonia Volatilization In Brazilian Tropical Soils

“…Besides the propitious conditions of the tropical climate, the increase in the number of areas cultivated with corn under no-till (NT system) is another key factor that favors the N-NH 3 losses. The areas under NT system have increased in Brazil due to the NT system advantages, such as increased organic matter content, reduced losses of soil and nutrients by erosion, and increased maintenance of soil moisture 12,13 . On the other side, in NT systems the presence of straw on the soil surface intensi es the N-NH 3 losses, particularly with the application of urea 14 , being 25% greater than the N-NH 3 losses in conventional tillage systems (T system) 3 .…”