Determination of the critical period of weed control in corn using a thermal basis.

AUTOR(ES)
FONTE

Pesquisa Agropecuaria Brasileira

DATA DE PUBLICAÇÃO

2011

RESUMO

Field studies were conducted over 3 years in southeast Buenos Aires, Argentina, to determine the critical period fo weed control in maize (Zea mays L.). The treatment consisted of two different periods of weed interference, a critical weed-free period, and a critical time of weed removal. The Gompertz and logistic equations were fitted to relative yields representing the critical weed-free and the critical time of weed removal, respectively. Accumulated thermal units were used to describe each period of weed-free or weed removal. The critical weed-free period and the critical time of weed removal ranged from 222 to 416 and 128 to 261 accumulated thermal units respectively, to prevent yield losses of 2.5%. Weed biomass proved to be inverse t the crop yield for all the years studied. When weeds competed with the crop from emergence, a large increase in weed biomass was achieved 10 days after crop emergence. However, few weed seedling emerged and prospered after the 5-6 leaf maize stage (10-20 days after emergence)

ASSUNTO(S)

weed interference weed management accumulated thermal units nonlinear regression interferencia de plantas daninhas manejo de plantas daninhas unidades termicas acumuladas regressao nao-linear

ACESSO AO ARTIGO

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