Relay intercropping systems of corn into sunflower

Abstract

With the objective of comparing corn (Zea mays L.) grain yield grown in relay planting into sunflower (Helianthus spp.), in two sowing dates, with that obtained as a sole crop, a two-year study was carried out in the state of Rio Grande do Sul, Brazil. Four treatments were tested in the 1989/90 growing season: relay planting of corn (Zea mays L.) into sunflower at 19 and 40 days after sunflower anthesis and corn as a sole crop planted in sequence to sunflower in both sowing dates. In 1990/91, two other treatments were added: corn as sole crop planted in sequence to corn sowed in the same date of sunflower. The effect to relay intercropping on corn yield planted 19 days after sunflower anthesis varied with the year. As In the first year corn yield was 33% less in the relay intercropped system into sunflower than in sole cropping system, in the second year corn yield was similar in both systems. These differences could be partially attributed to the use of different sunflower cultivars. In the second date of relay planting of com into sunflower, corn grain yields were similar to those obtained as a sole crop in both trials.