EFFECT OF DIFFERENT ORGANIC RESIDUES IN THE DEVELOPMENT AND IN THE PRODUCTIVITY OF LETTUCE (Lactuca sativa L)

The present study was done to verify the effect of organic and chemical fertilizations either together or separated, on the productivity of lettuce (Lactuca sativa L). The influence of chicken and cattle manure on the lettuce productivity was also verified. The field experiment was conducted at the Escola de Agronomia, U.F.G., Goiânia, Goiás (Brazil), in dark red latosol (oxisol), using the cultivar 'Reqina' (seeds from Vigoragro). The experimental design was completely randomized, with seven treatments, as follow: 1) testimony (without fertilization); 2) chemical fertilization + cattle manure; 3) chemical fertilization, without manure fertilization; 4) chicken manure (double of the recommended level), without chemical fertilization; 5) cattle manure (double of the recommended level), without chemical fertilization; 6) chemical fertilization + chicken manure; 7) chemical fertilization (double of the recommended level). All fertilizer levels followed the C.F.S. recommendations for the Goiás State, 1988. The results show that treatments 2, 5 and 6 were quite similar and presented higher performance in all analysed variables (weight, diameter and commercial value).