Effect of vermicompost extract (Compost tea) on growth and yield of strawberry

Unbalanced application of chemical inputs leads to environmental damage, which reduces the quality and health of the soil (Samavat, 2011) Vermicompost is one of the bio-fertilizers that results from a semiaerobic process by a specific species of earthworm called Fetida Eisenia and excretion of these substances from the body of the worm (Sekar and Karmegam, 2010). Compost tea, a vermicompost extract, has the beneficial properties of the vermicompost from which it is prepared. During extraction, dissolved inorganic nutrients, humic acid, fulvic acid, hormones and growth regulators are fed into the extract from Vermicompost (Afshar Manesh et al., 2016). This research was conducted with the aimof producing an organic crop and reducing the use of chemical fertilizers, as well as determining the best concentration of compost tea on the growth and yield of three cultivars of strawberry. This experiment was carried out in a factorial based on a completely randomized block design with three replications and two factors: A - concentration of compost tea at four levels (0, 1500, 3000 and 4500 ppm); B - three short-term cultivars of strawberry (Parous, Queen Eliza and Diamante) in the research sites of the University of Mohaghegh Ardabili in 2015-17. The compost tea solution was prepared in a ration 1:5. The extract was diluted with water to prepare each level of solution. The spraying of compost tea from the third stage of the strawberry bush (mid-April to late May) was carried out in five periods of 10 days apart from each other in each year. Two weeks after the last application of treatments (June of the second year), growth variables of the plant were measured, such as fresh and dry weight of leaves, leaf area, number of runners, fresh and dry weight of root, root length, chlorophyll a, b, and total chlorophyll, rate of flowers converting into fruits and fruit yield. Analysis of variance indicated that the effective compost tea has had a significant effect at 1% probability level on all traits. Comparison of meanings showed that the highest fresh weight (26.84 gr), dry weight of leaves (7.38 gr) and fresh weight of root (23.10 gr) were related to 4,500 ppm treatments. In all three indicators, the Parous (27.86 gr, 8.71 gr and 22.89 gr) responded better than the Diamante and Queen Eliza cultivars. The highest rate of flowers converted into fruit (93.55%), fruit yield in bush (181.73 gr), dry weight of root (8.79 gr) and root length (18.48 cm) resulted from the 3000 ppm application. The Parous also had the highest rate of flowers converted into fruit (93.60%), fruit yield in bush (162.02 gr), dry weight of root (8.74 gr) and root length (18.12 cm). Due to the interaction of treatments, the Parous with the 3000 ppm concentration of compost tea had the highest amount of leaf area (7533.75 cm2), chlorophyll a (1.65 mg.g-1FW), chlorophyll b (0.79 mg.g- 1FW) and total chlorophyll (2.44 mg.g-1FW). The highest number of runners (8.89) was observed in the treatment of Parous cultivar with 4500 ppm level of compost tea. It can generally be concluded that the application of compost tea as a foliar application on various cultivars of strawberry can improve plant growth and yield. According to the results of this experiment, the level of 3000 ppm of compost tea and Parous cultivar had the highest growth indices and yield of strawberry.