Ensaio de compactação em Latossolo cultivado com milho sob diferentes períodos de adoção de tipos de manejo

Abstract

RESUMODevido à necessidade de se mitigar a compactação do solo, sugere-se o uso preliminar do ensaio de Proctor para a obtenção de valores de referência. E para isso objetivou-se avaliar a influência dos sistemas e períodos de adoção de tipos de manejo por meio da densidade máxima e correlacionar a densidade relativa com o rendimento de grãos de milho e com outros atributos físicos do solo. O delineamento experimental usado foi o de blocos ao acaso, em parcelas subdivididas, com seis repetições, três camadas (0-0,10; 0,10-0,20 e 0,20-0,30) e os tratamentos foram: semeadura direta por 6 anos (SD6), SD8, SD10, respectivamente, preparo convencional (SC) e uma área adjacente de mata nativa (MN). Observou-se que o comportamento das curvas de compactação do solo foi o mesmo em todas as camadas e manejos. Nos Latossolos Vermelhos de textura média, as operações mecanizadas com os tipos de manejo estudados podem ser efetuadas na faixa de umidade 0,14 a 0,20 kg kg -1 sem causar degradação física. Palavras-chave: aeração do solo, matéria orgânica do solo, Proctor normal, Zea mays Soil compaction test in an Oxisol as affected by maize crop managed by different soil tillages ABSTRACTDue to the need for avoiding soil compaction, preliminary use of the proctor test is suggested to obtain reference values. For that purpose, the aim was to evaluate the effect of the systems and time periods of adoption of management techniques by means of maximum density and correlate relative density with maize yield and the others physical attributes of the soil. A completely randomized block design was used in split-plots with six replications and three soil layers (0-0.10, 0.10-0.20 and 0.20-0.30) and the treatments were: no-till planting for 6 years (NT6), NT8, NT10, respectively, conventional tillage system (CT) and an adjacent native forest area (NF). The results showed that the behavior of soil compaction curves was similar in all layers of all treatments. On the Red Oxisol under study, the mechanical operations required for the management systems can be performed in a moisture content 0.14-0.20 kg kg -1 , without causing physical degradation.

Silage yield, organic carbon content and physical attributes of a chiseled Ferralsol under an integrated crop-livestock system

“…In this sense, the reduced compaction degree in the chiseling was accompanied by an increase of the MA, and not only in the 0.05-0.10 and 0.20-0.30 m layers, but it was also significant for the 0.10-0.20 m layer. Rossetti & Centurion (2015) observed MA < 0.10 m 3 m -3 , which limits root growth (Lapen et al, 2004;Reynolds et al, 2009) in a medium texture Ferralsol when the ρ R value exceeded 0.89; a condition that was not determined in this work.…”

“…There was an effect of the treatments in altering the ρ R of the studied soil, which evaluates the soil compaction degree (Rossetti & Centurion, 2015;Drescher et al, 2016;Sá et al, 2016). The ρ R determined under the conditions of this experiment is above the 0.80 limit considered critical for most crops (Beutler at al., 2005;Sá et al, 2016).…”

“…However, according to Reichert et al (2017) only the ρ B value does not allow to infer that the adopted management causes soil compaction. Thus, other more sensitive attributes to compaction should be taken into account in order to evaluate the impacts of the management system on the physical quality of the soil, such as hydraulic conductivity (Allmaras et al, 1977;Drescher et al, 2016), aggregation (Calonego et al, 2017), penetration resistance (Drescher et al, 2016;Colussi et al, 2014;Reichert et al, 2017) and the compaction degree (Rossetti and Centurion, 2015;Drescher et al, 2016;Sá et al, 2016).…”

“…The ρ R determined under the conditions of this experiment is above the 0.80 limit considered critical for most crops (Beutler at al., 2005;Sá et al, 2016). However, in notillage systems the ρ R value considered as critical can be up to 0.90 due to the structural conditions that this system imposes on the soil (Rossetti & Centurion, 2015). Rossetti & Centurion (2015) evaluated the corn yield in a medium-textured Rhodic Ferralsol in no-tillage systems with different implantation times and observed ρ R values > 0.87, where the authors did not observe a reduction in crop yield.…”

“…However, in notillage systems the ρ R value considered as critical can be up to 0.90 due to the structural conditions that this system imposes on the soil (Rossetti & Centurion, 2015). Rossetti & Centurion (2015) evaluated the corn yield in a medium-textured Rhodic Ferralsol in no-tillage systems with different implantation times and observed ρ R values > 0.87, where the authors did not observe a reduction in crop yield. In addition, Sá et al (2016) concluded that ρ R > 0.88 limited the root growth of mechanized sugarcane (Saccharum officinarum) in a very clayey acric Rhodic Ferralsol under no-tillage.…”