Erosão hídrica em semeadura direta de milho e soja nas direções da pendente e em contorno ao declive, comparada ao solo sem cultivo e descoberto

Abstract

(4) RESUMO Dados de perdas de água e solo obtidos em estudos de erosão hídrica são necessários nos planos de conservação do solo. Mesmo com o advento do sistema de semeadura direta, difundido no Brasil a partir dos anos de 1970, ainda se fazem necessárias práticas conservacionistas para o efetivo controle da erosão hídrica, como o uso do cultivo em contorno e o terraceamento, especialmente em regiões com altos volumes de chuva. Outra opção para o controle da erosão é o uso de culturas protecionistas do solo. O objetivo deste trabalho consistiu em quantificar as perdas de água e solo por erosão hídrica, em um solo cultivado com soja e milho sob semeadura direta, nas direções da pendente e em contorno ao declive. O experimento foi realizado em um Cambissolo Húmico alumínico léptico, no período de 2010-2011, sob a aplicação de quatro testes de chuva simulada. Estudaram-se cinco tratamentos, com duas repetições, sendo eles: semeadura de soja no sentido do declive (SD); semeadura de soja no sentido da curva de nível (SC); semeadura de milho no sentido do declive (MD); semeadura de milho no sentido da curva de nível (MC); e testemunha -solo sem cultivo e descoberto (T). Os cultivos foram implantados sobre resíduo cultural de trigo, no sistema de semeadura direta. A semeadura da soja em contorno foi mais eficaz no controle das perdas de solo do que a semeadura dessa no sentido do declive. A cultura do milho foi mais eficaz no controle das perdas de solo do que a soja, independentemente da forma de semeadura, e ambas foram mais eficazes do que a testemunha. As perdas de água

Loss of Water and Nutrients in Different Soil Tillage Systems Subjected to Natural Rainfall in the State of Mato Grosso, Brazil

“…The largest water loss values in the plot with the CTDP soil tillage system corroborated the results obtained by Marioti et al (2013), who obtained the largest water loss results for treatments involving sowing in rows in the direction of the slope when evaluating the water and soil losses by water erosion in two sowing directions (sowing in rows in the direction of the slope and sowing in rows perpendicular to the slope).…”

Losses of soil, water, organic carbon and nutrients caused by water erosion in different crops and natural savannah in the northern Amazon

“…During July, due to the increased rainfall regime, it was possible to diagnose higher water losses in the treatment of BS, with 253.92 m 3 ha -1 month -1 (Table 3), statistically superior to the other treatments under study. Similar results were obtained by Panachuki et al (2011) and Marioti et al (2013). It was also observed that the CB treatment of 134.47 m 3 ha -1 month -1 presented higher water losses when compared to treatments of BB, CO, and SN (Table 3).…”

“…The erosivity index data (EI30) of evaluated months (Table 2) was obtained by method proposed by Wischmeier and Smith (1958), which is recognized world-wide as the R factor of USLE, and recommended for use in several regions worldwide, including in Brazil (North: Barros et al, 2009;South: Bertol et al, 2007;Cogo et al, 2003;Guadagnin et al, 2005;Marioti et al, 2013;Oliveira et al, 2015;Southeast: Cardoso et al, 2012;Dias et al, 2013;Pires et al, 2006;Silva et al, 2005aMidlewest: Leite et al, 2009Panachuki et al, 2011;and Northeast: Albuquerque et al, 1998).…”

Water Infiltration in Two Cultivated Soils in Southern Brazil

“…In soybean sown downhill, the infiltration coefficient was 0.06, while in the contour, it was 0.15; in corn sown downhill, the coefficient was 0.06, while in the contour it was 0.30, in the mean of the applied rains. The highest coefficient of infiltration observed in corn sown in the contour can be explained: the furrows of the seeder, along the contour lines, stored a larger volume of water and for a longer time compared to the other studied conditions, as observed by Luciano (2008), Marioti (2012) and Marioti et al (2013), in studies carried out in the same experimental area. The lower biomass production in common bean shoots, which mainly influenced rainwater interception, contributed to this.…”

“…Water infiltration is influenced by the soil type (Horton, 1940;Philip, 1957;Schwab et al, 1981), tillage and management (Leite et al, 2004;Bertol et al, 2006Bertol et al, , 2008Panachuki et al, 2011), crop type (Leite et al, 2004;Luciano et al, 2009;Bertol et al, 2013), surface roughness and cover by crop residues (Burwell and Larson, 1969;Panachuki et al, 2006;Zoldan Junior et al, 2008;Ramos et al, 2014), and soil water content prior to rain (Luciano et al, 2009;Marioti et al, 2013).…”