Resumo

TOUREIRO, C. M.; BRASI, F. C.; OLIVEIRA, M. R.  e  SERRALHEIRO, R. P.. Rooting pattern of sugar beet (Beta vulgaris L. var. saccharifera) in a soil from alluvium. Rev. de Ciências Agrárias [online]. 2007, vol.30, n.1, pp.500-509. ISSN 0871-018X.

Knowledge of plant rooting patterns and their evolution during the crop season is important for the apropriate soil water and nutrients management. The implementation of efficient irrigation practices – such as the irrigation management in real time for a certain area – needs information on meteorological, soil and crop parameters: such as crop growth stage, crop coefficients, paths of rooting depth, crop sensitivity to water stress, allowable soil water deficit, etc. Also, the characteristics of irrigation events should also be known, normally irrigation amount, opportunity, and evaluation. The objective of the present study is to evaluate a sugar beet crop growth including root growth pattern, on an Alluvial soil, under irrigation to give the crop the optimum water amount for maximum growth. The minirizotron method was used for monitoring root growth during crop season. Later on, trenches were opened for directly observing and measuring root development and pattern, up to 50 cm depth. Beet root depth and weight were evaluated at several points – growing stage from 0 to 69 days after seeding (DAS), yield formation from 69 to 166 DAS, and ripening from 166 to 196 DAS - and crop growth indices were also determined: leaf area index (LAI), and the duration of crop growing stages. Finally, biomass and grain production were evaluated. Data obtained showed that: 1) Maximum values for biomass and LAI were observed at 96 to 111 days, the values decreasing afterwards, while leaf senescence and rapid root growth occurred; and 2) Mass and depth of the beet root was observed to increase throughout the crop cicle, but faster between 96 and 111 DAS, reaching 2000 g and 40 cm respectively at 196 DAS. Images obtained with the minirizotron showed that fine beet roots had grown down to 90 cm depth.

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