Improving growth, yield and fruit quality of strawberry by foliar and soil drench applications of humic acid

Abstract

Organic compounds including seaweed extract were applied in organic production system and sustainable agriculture. One of these compounds is humic acid that was used widely in research and commercial programs. Humic acid is an organic acid obtained from humus and other natural resources with hormonal effects and improving nutrient absorption, increasing root and shoot biomass. In order to investigate the effect of foliar and soil drench applications of humic acid on growth responses of strawberry, this research was conducted as a completely randomized design. Well-rooted daughter strawberry cv. Paros plants were potted in 3 liter plastic pots filled with leaf mold, field soil and sand (1:1:1 v:v:v). After the establishment of plants, Greenhum (13.5% humic acid) was sprayed at 300, 600, 900, and 1200 mg L-1 and soil drench was applied at 300, 450, 600, and 750 mg L-1 (250 ml pot-1). Results showed that foliar application at 600 and 900 mg L-1 produced the highest dry mass of shoot and root. Total acid of fruit in 750 mg L-1 soil application and in 300 mg L-1 foliar application were significantly higher than untreated control plants. The greatest vitamin C and TSS were obtained from 900 and 600 mg L-1 foliar application treatments, respectively. The highest flower numbers and yield were produced in 900 mg L-1 foliar application. In general, foliar application of Greenhum, especially at 600 and 900 mg L-1, significantly increased most evaluated parameters.