Indicadores de qualidade estrutural na avaliaÃÃo da compactaÃÃo do solo em decorrÃncia da colheita mecanizada da cana-de-aÃÃcar. / Indicators of structural quality in the evaluation of soil compaction due to mechanized harvesting of sugarcane.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The mechanized harvesting of sugarcane in inadequate water contents in the soil has been responsible for soil compaction and reduction of yield in the later cycles of the crop. The identification of the impacts of mechanized harvesting of the sugarcane crop on soil structure, in different classes can become an important cropping strategy for minimization of the effects of soil compaction. In this context, the objectives of this study were: a) to evaluate the effect of the cropping operations of sugarcane at different times of the crop on compaction and; b) to evaluate the structural changes, the preconsolidation pressure and the least limiting water range (LLWR) in a Red-Yellow Latosol (LVA) and a Haplic Cambisol (CX), due to the harvest operations of sugarcane at different times of the crop. Undisturbed soil samples were collected at 0-5 cm depth to determine the bearing capacity models and quantification of soil compaction, structural changes and the LLWR, due the mechanized harvesting in the months of november of 2005, march and august of 2006, and manual harvesting without machine traffics, in march of 2006, which is the time of higher rainfall intensity. The soil water content during the harvest of sugarcane varied in the following order: august of 2006LVA in each time. CX presented larger resistance to compaction than the LVA. The mechanized harvesting of sugarcane in the range of friability caused soil compaction while the harvest of sugarcane accomplished manually did not promote the same effect. The bulk density in the preconsolidation pressure was a good indicative to diagnostic the occurrence of soil structural changes. Limiting soil macro porosity presented restrictions for plants growth at compaction levels smaller than the critical bulk density of LLWR. The mechanized harvesting of sugarcane accomplished in soil water contents up to 0,16 and 0,21 kg kg-1, for the LVA and CX, respectively, did not promote excessive soil compaction.

ASSUNTO(S)

ciencia do solo ciencia do solo

ACESSO AO ARTIGO

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