Physical quality of an Oxisol cultivated with maize submited to cover crops in the pre-cropping period

Abstract

SUMMARYThe intensive use of land alters the distribution of the pore size which imparts consequences on the soil physical quality. The Least Limiting Water Range (LLWR) allows for the visualization of the effects of management systems upon either the improvement or the degradation of the soil physical quality. The objective of this study was to evaluate the physical quality of a Red Latosol (Oxisol) submited to cover crops in the period prior to the maize crop in a no-tillage and conventional tillage system, using porosity, soil bulk density and the LLWR as attributes. The treatments were: conventional tillage (CT) and a no-tillage system with the following cover crops: sunn hemp (Crotalaria juncea L.) (NS), pearl millet (Pennisetum americanum (L.) Leeke) (NP) and lablab (Dolichos lablab L.) (NL). The experimental design was randomized blocks in subdivided plots with six replications, with the plots being constituted by the treatments and the subplots by the layers analyzed. The no-tillage systems showed higher total porosity and soil organic matter at the 0-0.5 m layer for the CT. The CT did not differ from the NL or NS in relation to macroporosity. The NP showed the greater porosity, while CT and NS presented lower soil bulk density. No ≤ ≤ ≤ ≤ ≤ 10 % airing porosity was found for the treatments evaluated, and value for water content where soil aeration is critical (θ θ θ θ θ PA ) was found above estimated water content at field capacity (θ θ θ θ θ FC ) for all densities. Critical soil bulk density was of 1.36 and 1.43 Mg m -3 for NP and CT, respectively. The LLWR in the no-tillage systems was limited in the upper part by the θ θ θ θ θ FC , and in the bottom part, by the water content from which soil resistance to penetration is limiting (θ θ θ θ θ PR ). By means of LLWR it was observed that the soil presented good physical quality.

Least limiting water range in soil under crop rotations and chiseling

“…Tormena et al (1998) obtained similar results in a clayey soil, that is, the θ AFP became the upper LLWR limit, substituting the θ FC , with Db of 1.28 g cm -3 , with a soil volumetric moisture of around 0.42 cm cm -3 . However, Pereira et al (2010) did not observe θ AFP as the upper limit of LLWR for all Db values obtained, due to a high sand content (642 g kg -1 ).…”

Propriedades físicas do solo em área sob milho em monocultivo ou consorciado com leguminosas de verão

“…Assim, para observar possíveis variações desse atributo, normalmente são necessários estudos com um período de avaliação superior ao dedicado neste experimento. Variações da microporosidade foram observadas por Pereira et al (2010), os quais avaliaram plantas de cobertura em pré-cultivo e diferentes sistemas de preparo do solo durante mais de cinco anos. Portanto, o aumento na porosidade total observado neste experimento (Quadro 2) deve-se ao incremento de macroporos.…”

Structuring of a Haplortox by Soil Cover Species

“…To the system of no-tillage, characteristics of minimal mobilization are attributed to the soil constituents, which are essential to the plants development, supporting root growth, providing water, oxygen, nutrients (Amaral et al, 2004;Pereira et al, 2010) and soil surface protection (Bertin, Andioli, & Centurion, 2005).…”