Trichoderma, Lactuca sativa, biological control agent, Organic/ecological horticulture
Abstract
Effects of Trichoderma harzianum on lettuce seedling development, plant quality characteristics at harvest and yield were investigated. Experiments were carried out in an unheated glasshouse where composted straw bales were used as the growing medium. A part of the experiment was carried out in a high tunnel where soil was the growing medium. Seeds were sown in peat and seedlings were grown in the presence of T. harzianum at dosages of 5, 10 and 15 g
m-2 applied at sowing. Among the seedling characteristics studied only seedling fresh weight of cv. Yedikule was increased significantly. Effect of T. harzianum on lettuce yield was not statistically significant. In the glasshouse, the straw bales were composted with two different methods. In the method I, 134g N, 13g P, 25g K, and 76 g Ca, and in
the method II, 54.3g N, 26g P, and 22.6g Ca were provided to the straw bales. The marketable yield of cv. Yedikule from the straw bales of method I was 503 g plant-1 from 15 g m-2 whereas the control remained the lowest with 425 g plant-1. For the same cultivar grown on the method II the highest marketable yield was obtained from 10 g m-2 with 303 g plant-1 compared to the control (150 g plant-1). The cv. Coolguard grown in the straw bales was tested only with the method I and the highest yield was from 15 g m-2 with 570 g plant-1 compared to 551 g plant-1 from the control. Dosage main effect regarding marketable yield in soil in the tunnel was not significant.
