Faixa de umidade menos limitante ao crescimento vegetal e sua relação com a densidade do solo ao longo do perfil de um latossolo roxo

ABSTRACT:A compacted subsurface soil layer can be a limiting factor for soybean growing, reducing soybean yield. The aim of this study was to evaluate the effect of different tillage systems on the physical properties of two Albaqualf soils of the Central Plains region in the state of Rio Grande do Sul in southern Brazil. Two experiments were conducted: one in Santa Maria, RS, during the 2013/14 and 2014/15 crop seasons, and another in Formigueiro, RS, during the 2013/14 crop season. A randomized block experimental design with four replications was used. The treatments were: sowing using an offset double disc (T1); sowing using a fluted coulter disc (wavy disc with 12 waves) (T2); sowing with a knife runner opener (T3); sowing with a knife runner opener + press wheel mechanism for ground levelling (T4); sowing using a furrow opener upon a raised bed (T5); and chisel plough + sowing using an offset double-disc (T6). In the 2014/15 growing season, the T4 factor was changed using a knife runner opener 0.05 m from the planting row. A smaller reduction in the compacted subsurface soil layer was observed for both T1 and T2, which exhibited high soil bulk density values for the 2013/14 and 2014/15 crop seasons. Furthermore, T3, T5 and T6 led to a reduction in bulk density, and increasing total porosity and macroporosity in the soil, which consequently increased water infiltration, water storage capacity, and crop yield in areas with the presence of a compacted subsurface soil layer.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Soybean Tillage Systems and Physical Changes in Surface Layers of Two Albaqualf Soils

Sartori

Marchesan

David

et al. 2016

“…Following the incorporation of Oxisols into productive agricultural systems, structural alterations and soil compaction have been observed (Tavares Filho et al, 1999;Klein & Libardi, 2000;Tavares Filho et al, 2001;Giarola et al, 2007). The soil physical characteristics are interdependent and an alteration in any of them normally leads to changes in the soil system as a whole (Vieira, 1989).…”

Section: Introductionmentioning

confidence: 99%

Characterization of soil structure and porosity under long-term conventional tillage and no-tillage systems

Filho

Tessier

2009

Different management systems tend to modify soil structure and porosity over the years. The aim of this study was to study modifications in the morphostructure and porosity of dystroferric Red Latosol (Oxisol) under conventional tillage and no-tillage over a 31-year period. The study began with the description of soil profiles based on the cropping profile method, to identify the most compact structures, define sample collection points for physical and chemical analysis, and determine the water retention curve. A forest soil profile was described and used as reference. The results showed that, under conventional tillage, the microaggregate structure of the Oxisol was fragmented between 0 and 0.20 m, and compact (bulk density = 1.52 Mg m -3 ) in the sub-surface layer between 0.20 and 0.50 m. Under no-tillage, the structure became compacted (bulk density = 1.40 Mg m -3 ) between 0 and 0.60 m, but contained fissures and biopores. The volume of the class with a pore diameter of ≥ ≥ ≥ ≥ ≥ 100 μ μ μ μ μm under no-tillage was limited, but practically non-existent in the conventional management system. On the other hand, the classes with a pore diameter of < 100 μ μ μ μ μm were not affected by the type of soil management system. Index terms: Latosol/Oxisol, soil management, cropping profile method, water retention curve.(

“…Em razão disso, a quantidade de água retida a determinadas tensões varia, o que torna o conceito de água no solo disponível às plantas não tão simples de ser interpretado. Em solos compactados, a deficiência de aeração e a resistência mecânica do solo à penetração das raízes (RP), comumente, são limitantes ao desenvolvimento das plantas, mesmo havendo água disponível (Klein & Libardi, 2000).…”

Section: Introductionunclassified

Rendimento da soja e intervalo hídrico ótimo em latossolo vermelho sob plantio direto escarificado

Klein

Camara

2007

Self Cite

O intervalo hídrico ótimo (IHO) é um método que integra vários fatores que afetam o desenvolvimento das plantas, e corresponde ao intervalo de umidade do solo no qual não ocorre restrição de aeração (porosidade de aeração mínima de 0,10 m³ m-3) nem de resistência mecânica à penetração das raízes (RP) dentro da faixa de água disponível às plantas, isto é, entre a capacidade de campo (CC) e o ponto de murcha permanente (PMP). O objetivo deste trabalho foi determinar o IHO em um Latossolo Vermelho sob plantio direto (PD) e plantio direto escarificado (PDE), bem como o rendimento de grãos de soja. Avaliou-se a densidade do solo, o IHO, a variação da umidade do solo durante o ciclo da soja e o rendimento de grãos. Os resultados indicaram que a densidade do solo foi menor no PDE, o que acarretou maior amplitude do IHO. A densidade crítica, na qual IHO = 0, foi semelhante entre o PD e o PDE. Durante o ciclo da cultura da soja, em vários momentos, a sua umidade ficou fora do IHO, quando assumida RP limitante de 2 MPa. Como o rendimento de grãos da soja não apresentou diferença significativa, deduz-se que a RP de 2 MPa não é limitante para a soja.