The lettuce (Lactuca sativa L.) is a very demanding crop for phosphorus, being little tolerant to the soil acidity. The response of the lettuce crop to sources of soluble and reactive phosphorus fertilizer of slow solubility was evaluated in the presence of liming. . The experimental design consisted of a randomizing complete block design with six treatments (single superphosphate, thermalphosphate magnesium, triple superphosphate, Fosmag, Arad phosphate rock and control without phosphorus), in four replications, conducted in a Typic Acrustox. P suppression, yield and plant diameter indicate, as well as all other variables related to plant growth, the importance of P for the lettuce development. Significant responses to different P sources were also observed for fresh and dry matter production of aerial part, fresh mass of roots and level of P in the soil. Best responses in decreasing order were obtained for Fosmag, triple superphosphate, single superphosphate, thermalphosphate magnesium and Arad phosphate rock match sources. Fosmag and triple superphosphate were equivalent for production of root dry mass and diameter of the aerial part. Adjusting soil acidity, the accumulated level of P in leaves was higher when Fosmag, triple superphosphate and simple superphosphate were used as sources of P.
Lactuca sativa L.; liming; fertilization; phosphate
