Appearance of spontaneous plants from disturbed and undisturbed soil under mediterranean conditions
José Manuel Godinho Calado1, Gottlieb Basch2, Mário de Carvalho3
RESUMO
A diminuição da perturbação do solo é de extrema importância para a manutenção e preservação dos sistemas agrícolas. Por isso, o estudo realizado neste trabalho tinha como objectivo verificar o aparecimento das plantas espontâneas a partir do solo com e sem perturbação.
A população de plantas emergidas inicialmente, no Outono, foi controlada com perturbação do solo através da simulação da mobilização realizada pelo escarificador e sem perturbação do solo em que se aplicou um herbicida total e não residual. A experimentação foi efectuada em solos Mediterrâneos durante quatro anos, com um delineamento experimental em blocos casualizados e oito repetições.
De acordo com os resultados, verifica-se que a perturbação do solo efectuada para controlar a flora espontânea no Outono influencia significativamente o aparecimento das plantas em condições mediterrânicas e permite obter maior densidade populacional, que aumenta com o acréscimo da precipitação acumulada. Daqui conclui-se que em sistemas com diminuição da perturbação do solo, como por exemplo, de sementeira directa, é possível decrescer a infestação nas culturas de Outono-Inverno.
]]> Palavras-chave: controlo da flora, densidade populacional, emergência, infestação de culturas.
ABSTRACT
The reduction of soil disturbance is extremely important for the conservation of soil and thus for the sustainability of agricultural systems. Soil disturbance interferes with a number of soil parameters including its fauna and flora. This paper deals with the comparison of the appearance of spontaneous plants from disturbed and undisturbed soil.
A study was conducted to compare the appearance of spontaneous flora in autumn after the simulation of soil tillage by a tine cultivator with the control of the already emerged plants through the application of a total herbicide and without any soil disturbance. The trials were realized on typical Mediterranean soils (Luvisol) over a period of four years in a completely randomized block design and with eight replications.
The results provide evidence that soil disturbance in autumn before crop establishment to control the spontaneous flora increases significantly the appearance of spontaneous plants under Mediterranean conditions and that this increase is even more pronounced in years with higher accumulated precipitation. This allows the conclusion that production systems based on low soil disturbance and especially no-till are able to decrease the population density of weeds in winter crops.
Keywords: weed control, population density, plant emergence, weed infestation
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1, 2, 3 Universidade de Évora, Departamento de Fitotecnia, Apartado 94, 7002-554 Évora. E-mail: 1 jcalado@dfit.uevora.pt.
1, 2, 3 Instituto de Ciências Agrárias Mediterrânicas, Apartado 94, 7002-554 Évora.
Recepção/Reception: 2007.11.13 aceitação/acception: 2008.06.23
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