Modelos de capacidade de suporte de carga de um Latossolo submetido a diferentes sistemas de manejo de plantas daninhas em lavoura cafeeira / Bearing capacity models of a Latossol submitted to different weed management system in coffee crop.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The determination of the pressures that can be applied to the soils submitted to different weed management systems is important to adapt the coffee crop management in a sustainable way. The objectives of this study were: a) to develop the bearing capacity models for a Red-Yellow Latossol (LVA) cultivated with coffee and submitted to different weed management systems; b) to determine through the use of these models the pressures that can be applied to the soils to avoid the soil compaction; c) to identify the weed management system more resistant or susceptible to soil compaction. This study was carried out in the experimental farm of Epamig in the PatrocÃnio County, MG, in a farming planted with Ruby 1192 coffee variety in 3,8 x 0,7 m spacing. The weed management systems studied were in the inter rows: without hoeing (SC), hand hoeing (CM), post-emergence herbicide (HPÃS) and pre-emergence herbicide (HPRÃ) and in the canopy of the coffee plant: roÃacarpa (RÃ), hand hoeing (CM), post-emergence herbicide (HPÃS) and pre-emergence herbicide (HPRÃ). In each manegement system 15 undisturbed samples, were collected randomly at 0â3, 10â13 and 25â28 cm depth, totaling 900 soil samples [15 samples x 3 depths x 20 (4 weed manegement systems in the inter rows + 16 under cannopy of the coffee plant)]. The undisturbed soil samples were used in the uniaxial compression test to obtain the preconsolidation pressure (sp) at different moisture content and initial bulk density (Dsi). From the surplus of the undisturbed soil samples it was determined the texture, the organic matter (MO), the particle density, the total porosity (VTP), the field capacity (CC), the permanent wilting point (PMP) and the oxides. In the inter rows the weed management system more susceptible to soil compaction was the HPRÃ at 25â28 cm depth while the HPRÃ at 0â3 cm was the most resistant. Under the canopy the RÃ was most susceptible to soil compaction at of 0â3 cm depth and the HPÃS and the HPRÃ, the most resistant. At 10â13 cm depth under the canopy the HPRÃ was most resistant to compaction and the RÃ and the CM and the HPÃS the most susceptible to soil compaction. At 25â28 cm depth, the HPRÃ under the canopy associated with the HPÃS in the inter rows was the most resistant to compaction, while the manegement HPÃS under the canopy associated with the CM in the inter rows the most susceptible. To estimate the bulk density above wich the soil is compacted, the following equation was obtained: Dssp = 1,12 x Dsi. For the conditions that this work was developed it is recommended as an ideal weed management the use of the HPÃS in of the inter rows associated with the HPRÃ and the HPÃS in the canopy of the coffee plant.

ASSUNTO(S)

pressÃo de preconsolidaÃÃo resistant and susceptible produÃÃo dos cafeeiros uniaxial compression test compactaÃÃo do solo soil compaction fisica do solo manejo do solo preconsolidation pressure resistÃncia e susceptibilidade compressÃo uniaxial production of the coffee plants

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