Effect of vermicompost tea addition methods on growth and yield of lettuce (Lactuca sativa)

Low soil fertility results in lower productivity. Constantly exposed to chemical fertilizers leads to the health risks. The focus recently faces to organic productivity. Vermicompost is one of an important organic fertilizer, its beneficial for sustainable production. Therefore, this study was conducted at research station in Department of Horticulture and Landscape/ College of Agriculture/ Tikrit University to evaluate the addition of vermicompost with high advantages in the growth and yield of lettuce in different methods viz, control (C), add regular soil mixed with soil (V1), add compost tea in one batch (V2), add compost tea in two batches (V3), dilute compost tea to 50% concentration and add twice (V4) and dilute compost tea to 25% concentration and add weekly in four batches (V5). The experiment was laid out according to Randomized Complete Block Design (RCBD) The comparison of means was performed by Least Significant Difference at a P≤ 0.05 probability level. Results showed that V4 gave significant increment in chlorophyll, percentage dry matter, nitrogen, phosphorous and potassium in leaves, additionally organic matter nitrogen, phosphorous and potassium in soil. On the other hand, V1 had highest values in root weight, length of largest leaf and stem diameter. Meanwhile, V5 treatment increased significantly in total number of leaves, Width of largest leaf and percentage of oil in leaves. This indicates the importance of adding vermicompost, either directly or as compost tea at a concentration of 50% in two batches, in improving soil properties and lettuce growth and yield characteristics.