Horticultural Science and Technology ISSN:1226-8763(Print) 2465-8588(Online) 원예과학기술지

The objective of this study was to determine the effect of fertilization dosage on seedling growth, flowering response, and fruit yield of strawberry plants. Mother plants of the ‘Maehyang’ and ‘Seolhyang’ were planted on April 5, 2013. Daughter plantlets were proliferated in seedling trays with 24 cells. Each conical cell consisted of a 135 mL cup filled with a mixture of substrate and commercial fertilizer (11-11-17, 6 weeks, Osmocote®) at four different ratios: 1) N, P, K was supplied at 0-0-0 mg per daughter plantlet, 2) 25-11-32 mg, 3) 50-22-63 mg, and 4) 100-43-127 mg. Higher fertilization levels produced plantlets with increased crown diameter, leaf area and dry weight. Increased fertilization levels resulted in more large- and medium-sized plantlets and less small-sized plantlets. The N, P and K contents in the leaves also increased. The flower bud initiation time of ‘Maehyang’ plants treated with N, P, K at 0-0-0 mg, 25-11-32 mg, and 50-22-63 mg was earlier (September 13) than the flower bud initiation time of plants with N, P, K at 100-43-127 mg. The first flower budding time of ‘Maehyang’ plants treated with N, P, K at 100-43-127 mg was delayed by 11 days, but the second flower budding time was shortened by 9 days. The flower bud initiation of ‘Seolhyang’ plants occurred later when the level of fertilization was increased. The date of flower bud initiation was the earliest (September 13) under N, P, K at 0-0-0 mg treatment, and it was delayed by 4, 9, and 19 days in response to treatment with N, P, K at 25-11-32 mg, 50-22-63 mg, and 100-43-127 mg, respectively. The first harvesting time under treatment with N, P, K at 50-22-63 mg and 100-43-127 mg was delayed by 10 and 27 days, respectively. Both cultivars showed earlier first harvesting time with lower fertilization levels, resulting in increased fruit yield from November to January. For ‘Maehyang’ plants, the yield under N, P, K at 100-43-127 mg treatment was the highest in January and Febuary. However, for ‘Seolhyang’ plants, the yield was the highest in January but the lowest in February. The total yield of ‘Maehyang’ plants (from November to May) under the four different fertilizer treatments was not different, ranging from 3,339 to 3,518 kg. However, for ‘Seolhyang’ plants, the total yield was the highest (5,106 kg) under the N, P, K treatment at 0-0-0 mg, and it was reduced by approximately 12% in the treatments with N, P, K at 50-22-63 and 100-43-127 mg. These results show that increased fertilization levels delayed the initiation time of the first inflorescence and the first harvesting time. For cultivars that are sensitive to nitrogen fertilization levels such as ‘Seolhyang’, fertilization levels higher than 50 mg nitrogen during seedling period, could delay flowering and cause excessive fruit load of the first cluster and result in reduced total fruit yield. For cultivars such as ‘Maehyang’ which are less sensitive to nitrogen fertilization levels, higher fertilization levels could promote successive flower budding, thus increasing an early yield with higher market value.