Interferência de plantas daninhas na cultura do feijão em sistemas de plantio direto e convencional

Abstract

The common bean (Phaseolus vulgaris L.) stands out for its importance in human nutrition. The low productivity of beans in the Northeast of Brazil shows the need of changing in the current production system. Among the various factors that contribute to low productivity of bean, it stands out the weed interference. The adoption of cultural control such as no-till system can decrease the population of weeds by reducing the critical period of interference and consequently reducing the need for hoeing or herbicide application. Based on the above considerations, this study aimed to evaluate the weed community and his interference in common bean grown in no-tillage and conventional tillage systems associated with control strategies weed. Two experiments were carried out, the first one in 2014 and the second in 2015. They were carried out in a randomized strip block design with four replications. In the plots were located the tillage systems (no-tillage and conventional tillage) and in the subplots the seven control periods (0, 10, 20, 30, 40, 50 and 60 days after emergence - DAE), in which the weeds were controlled and seven periods of coexistence, (0, 10, 20, 30, 40, 50 and 60 days after emergence - DAE), in which the weed coexisted with the crop. 43 species and 19 plant families of weeds were identified. The species with the highest importance of value index - IVI were: Ageratum conyzoides, Digitaria sanguinalis, Galinsoga parviflora, Cyperus rotundos, Emilia fosbergii, Richardia brasiliensis and Eleusine indica. The monocotyledons presented higher IVI in the conventional tillage, while in the dicotyledons the IVI was higher in no - tillage. The monocotyledons presented higher IVI in the conventional tillage (Mentrasto) presented a greater capacity of competition with a bean crop in both tillage systems, since the sanguinary Digital was most important in conventional planting system. The species Ageratum conyzoides L. presented the greatest capacity of competition with the bean crop in the two systems, while the Digitaria sanguinalis was more important in the conventional tillage. Finally, the no-tillage system was superior to the conventional with respect to weed control, increasing the growth and productivity indicators of the common bean cultivated under the Coastal Plains soil conditions.