Vermicompost Application and Growth Patterns of Lettuce (Lactuca sativa L.)

Lettuce is the most important leaf vegetable grown in Argentina mainly in the green belts. This species requires 90 to 100 kg ha-1 nitrogen, which can be supplied by synthetic chemical fertilizers or organic supplements. The objective of this work was to evaluate the effect of the application of vermicompost on the growth parameters of lettuce in two commercial types: leaf lettuce (cv Brisa) and butterhead (cv Daguan). Seedlings were produced in plastic trays and were transplanted when two leaves were completed expanded 30 days after sowing after that management was similar to a commercial one. The experimental design was a randomized complete block with four replications. During cultivation and at harvest measurements of fresh and dry weight, leaf number and area, nitrate and reducing sugar concentrations were made. Calculations for yield were performed. At harvest, vermicompost addition affected nitrate content in leaf lettuce (cv Brisa) increasing its concentration. Yield was not affected by vermicompost application.