Alelopatia de adubos verdes sobre Cyperus rotundus Allelopathy of green manures on Cyperus rotundus

The objective of this study was to evaluate the allelopathic effect of soil incorporation of straw of different species of green manure (SGM) on the dry weight of purple nutsedge (Cyperus rotundus). The experiment was conducted at the State University of Mato Grosso do Sul - Unit Aquidauna, sector Plant Science, MS, Brazil. The SGM used were Mucuna aterrima, Mucuna deeringiana and Cajanus cajan and area where the soil remained without vegetation cover and highly infested with C. rotundus (witness). The dry biomass (DB) of the weed emerged plants was quantified at 7, 14, 21 and 28 days after incorporation of vegetation (DAIV) for each 1 m² plot. At 28 DAIV, per plot, the number of purple nutsedge tubers (NT) was counted in a soil volume of 8,000 cm³. Thereafter the tubers were planted in gerboxes filled with sand and placed in a green house type BOD to obtain the percentage of germination of tubers (GT). The DB of the nutsedge increased linearly over the course of the DAIV of SGM biomass where M. aterrima had the highest allelopathic effect on nutsedge, greatly reducing the BS, NT and GT this weed.