Economic analysis of the intercropping of lettuce and tomato in different seasons under protected cultivation

摘要

Lettuce and tomato are vegetables that can be grown in protected cultivation, under given conditions. Considering their expensive production systems, intercropping might be an excellent alternative to optimize costs. Four experiments were carried out at the S?o Paulo State University (UNESP), at Jaboticabal, Brazil, to study the economic viability of intercropping lettuce and tomato under protected cultivation. To set the intercropping, lettuce was transplanted 0, 10, 20, and 30 days after transplanting (DAT) tomato and vice-versa, in two seasons, namely April to September 2003 and January to June 2004, when monocultures of both vegetables were also carried out. At the first planting season, operational profits (OP) in intercropping (lettuce transplanted 0, 10, and 20 DAT tomato) were higher than in monocultures. At the first season, the return rates (RR) and OP were very much alike, whereas at the second season, RR in intercropping were lower than in monoculture. Transplanting tomato after lettuce, at both the first and second seasons, resulted in higher OP than those in monocultures. RR, OP and the profitability index (PI) were higher at the first than at the second season, independent of the growing system. RR in intercropping, independently of the intercropping schedule, were higher than in monoculture. In general, PI of tomato in monoculture and in intercropping were quite similar and both were higher than PI in the monoculture of lettuce. The economic indexes confirmed the agronomic viability (expressed by the index of area use efficiency) of transplanting lettuce and tomato simultaneously in both growing seasons; transplanting lettuce 10 and 20 DAT tomato, in the second season; and transplanting tomato after lettuce in all studied schedules. The economic indexes reached their peaks when tomato and lettuce were transplanted at the same day, in the first growing season (in average): OP of BRL$ 12,948.63 (US$ 4,273.48) in 614.4 m-2; RR of 6.7% and IP of 85%.