An intercropping system between lettuce and radish was devised so as to study the effects on yield of different starting moments for the intercropping, as well as different row distances. The experiment was carried out at UNESP, in Jaboticabal, from May to August, 2001. Fourteen treatments were distributed in a randomized complete block design, with four replicates. Each plot consisted of 20 plants which resulted from the combination of the following factors: two distances between rows (0.3 and 0.4 m), two cultivation systems (intercropping and sole crop), and three radish sowing moments (0; 7; and 14 days after lettuce transplantation), meaning that the intercropping system started at three different moments. Cultivars Taiá (lettuce) and Crimson Gigante (radish) were used. Due to a level stand, radish as a sole crop yielded more than the highest yield under intercropping. Nevertheless, when yield was evaluated per area unit (g m-1), the highest yield (518.8 g m-1), was significantly higher than when radish was cultivated as a sole crop, wich resulted from the intercropping established by sowing radish 14 days after lettuce transplantation (DAT). The delay in radish sowing resulted in significant increment in yield of commercial radish roots. The distance between lettuce rows had no significant effect on fresh mass of the aerial part (MFPA) of the border row plants. However, MFPA of the inner row plants decreased significantly when the distance between rows was reduced from 0.40 m (460.3 g) to 0.30 m (321.1 g). The intercropping and the single crop systems did not lead to significant differences in the yield of lettuce plants in the inner row (434.9 and 542.9 g, respectively) when lettuce and radish cultivation started at the same moment. A similar behavior was observed for border row plants when the intercropping took place up to 7 DAT. When the intercropping was established later, the yield of lettuce as a single crop was always higher than when intercropped. Independently of the intercropping system and distance between plant rows, the Land Efficiency Use indices were always higher than 1.0.
Lactuca sativa; Raphanus sativus; cultivation system; intercropping
