Dynamics of populations of weed in the sugarcane in system no-tillage and conventional one1

Abstract

The research aimed to evaluate the incidence and the populations dynamics in sugarcane crop in no-tillage system in comparison to the conventional one. The experimental design was completely random, using four replications, in a factorial 4x2 outline. The treatments were: (I) – sugarcane PC incorporated to spontaneous vegetation with manuring and (II) – the same procedure as in I without manuring; (III) – sugarcane SPD over jack bean (Canavalia ensiformis) with manuring and (IV) – the same procedure as in III without manuring; (V) – sugarcane SPD over velvet bean (Mucuna aterrima) with manuring and (VI) – the same procedure as in V without manuring and (VII) – sugarcane SPD over sunnhemp (Crotalaria juncea) with manuring and (VIII) – the same procedure as in VII without manuring. The species Cyperus rotundus and Sorghum halepense presented the highest rates of value of importance in the experimental area. Sugarcane SPD over jack bean presented the lowest similarity rate in the community of weed in relation to the sugarcane cultivated conventionally. The incidence of weed in the sugarcane PC was 531 and 525% superior in to the sugarcane SPD, and contributed to the reduction of 27% in the yield.