Períodos de interferência de plantas daninhas na cultura do feijoeiro em diferentes sistemas de cultivo

Abstract

Among the factors that can interfere with the productive potential of the culture of the bean are the weeds, especially in places that already have a history of appearance and possess a vast seed bank, caused by faulty control. Thus, the objective of this work was to evaluate the effect of different eras of weed management on fitossociológicos indexes and determine periods of weed interference on income in the culture of the bean, conducted in conventional tillage and no-tillage. The experimental design used was the random block (DBC), with 4 repetitions. Two experiments were conducted, one in no-tillage and conventional tillage, one in each of the two models of plantations, initially clean and dirty initially. The initially clear was conducted with periodic weeding until the period established by the treatment. Already the dirty initially was conducted with periodic weeding from the date established. The treatments in the model initially cleared were: T1 (7 days after emergence-DAE), T2 (14 DAE), T3 (21 DAE), T4 (28 DAE), T5 (35 DAE) and T6 (70 DAE-witness). The treatments in the model initially dirty were: T7 (7 DAE), T8 (14 DAE), T9 (21 DAE), T10 (28 DAE), T11 (35 DAE) and T12 (70 DAE-witness). Community assessments were carried out, and weed through formulas phytosociology indices were measured. The results were submitted to analysis of variance (ANOVA) and averages compared by regression to 5% probability of error. The results showed that the species Sorghum halepense, was the most important weed in both experiments, on weed community, having its relative frequency values, relative dominance and relative importance. In the experiment in no-till there was loss of 93.7% between the treatment of higher output and lower, with the period before the interference (PAI) of 7 DAE, critical period of interference prevention (PCPI) of 7 to 20 DAE and total period of interference prevention (PTPI) before the interference (PAI) of 8 DAE, critical period of interference prevention (PCPI) of 8 to 30 DAE and total period of interference (TPIC) of 30 days.