This study tested the effect of spacing between rows, cultivars and weeding periods on peanut yield. The trial was carried out in the Jaboticabal rcgion, São Paulo, Brazil, on Latossolo Vermelho Escuro soil, medium texture. The experimental was in a completely randomized block design with three replications. The treatments consisted of two peanut cultivars (Tatu and Tatuí), combined with two row spacing (0.4 and 0.6 m) and eight weeding periods (no weeding, weeding until 10, 20,30, 40, 50, and 60 days after emergence and hand weeding) throughout the crop cycle. The number of seeds per meter of row was equal within both spacings and cultivars; the rate of fertilizer applied was calculated per unit area. Pennisetum setosum was the main weed in the experimental area. ln the 0.4 m spacing, 10 days were enough to reduce the dry weight of the weeds, whereas, on spacing of 0.6 m 30 days were necessary for weed control. The number of pods per plant was the main yield component affected by the weed community and, as a consequence, pod and grain yield per unit of area were affected. The weeding periods were not influenced by peanut spacing. Cultivar Tatu had to be maintained free of weed interference for 20 days and cultivar Tatuí for 10 days after peanut emergence to prevent yield loss.
Arachis hypogaea; Pennisetum setosum; competition