Doses of organic compost were evaluated on crisp head lettuce production and quality in an experiment conduced in Três Pontas, Brazil, from July 8>th to August 30th. The experimental design was in randomized complete blocks with four replicates, the treatments being constituted by five doses of organic compost (0.0; 20.0; 40.0; 60.0 and 80.0 t ha-1). Total fresh matter showed a quadratic effect, in which the maximum yield of 914.2 g plant-1 was obtained with the dose of 59.4 t ha-1 of organic compost. For commercial fresh matter, the maximum yield (634.3 g plant-1) was obtained with the dose of 56.1 t ha-1. The greatest commercial head circumference (41.4 cm) was obtained with the dose of 53.7 t ha-1. The dose of 42.7 t ha-1 caused a maximum stem length of 3.9 cm. These results permit to conclude that the use of 56.0 t ha-1 of organic compost applied in pre plant provides an increase in yield and commercial quality of crisp head lettuce.
Lactuca sativa L.; yield; head circumference; stem length; organic manure
