A field experiment was conducted from November, 1998 to May, 2001 in a Cambic Yellow Red Argisol soil, with high fertility, in Viçosa, MG. The objective of this study was to evaluate the effects of soil management systems on purple nutsedge (Cyperus rotundus) populations. A high (720 ± 130 plants m-2) nutsedge infestation prevailed in the experimental area before the installation of the experiment. The treatments consisted of two soil management systems (conventional and no-tillage) and two corn use purposes (grain and silage) cultivated with autumn-winter beans in succession to corn, in blocks with four replications. Under conventional tillage, the soil was moldboard plowed before planting, and under no-tillage, weed desiccation was carried out with glyphosate + 2,4-D. The purple nutsedge population evaluations in the corn crop occurred at 20 and 55 days after emergence (years 1999/00) and at 20 days after emergence (years 2000/01), and in the beans crop at 20 and 40 days after emergence. The tuber bank was evaluated after corn harvest, during the last year, by determining density, biomass and percentage of sprouting of the sampled tubers. There was a reduction of purple nutsedge populations in no-tillage systems in both corn use purposes throughout the experiment. For both corn use purposes (grain or silage), there was a reduction in the tuber bank under no-tillage, with dormancy prevailing in comparison to conventional tillage.
herbicides; no-tillage and conventional tillage; Cyperus rotundus
