Effect of Organic Fertilizer on Tomato Growth and Production under Soil-less System

Soil-less system constitutes an efficient approach for the cultivation of tomato; however, organic liquid amendments are very limited under such systems. The current experiment aimed to evaluate the effects of Kurojiru (K), an organic liquid fertilizer and fulvic acid (FA) on the growth and production of tomato, Solanum lycopersicum L. cv. ‘Momotaro’. Recently, it is desirable to reduce the environmental impact and fertilizer cost by lowering the concentration of inorganic components in the culture medium. Therefore, we explored the effect of adding these organic fertilizers on the yield and quality of tomatoes by gradually reducing the phosphoric acid concentration in the culture medium (87, 58 and 29 mmol・pot-1・week-1). The whole experiment was conducted for 20 weeks (from seeding until harvesting). The plant biomass, tomato fruit weight and chlorophyll content were measured. The fresh weight (FW) of both root and shoot indicated a progress response according to phosphorus concentration in liquid media, in FA treatments. Total fresh weight was significantly higher in the treatment with K+FA than in the control. Additionally, the yield responded to the all treatments within the 58 mmol P. Especially, in this level of P the relative fruit weight was higher only under K application. The chlorophyll content responded K+FA treatment under a low P content (29 mmol), and to all of those in 58 mmol. These results indicate that Kurojiru has some positive effects on tomato growth in soil-less systems.