Analysis of yield components and dry matter production in a simplified soilless tomato culture system by using controlled-release fertilizers during summer–winter greenhouse production

Abstract

We investigated the use of a simplified soilless tomato culture system fertilized with controlled-release fertilizers (CRF) in northern Japan. The utility of this system was assessed by measuring plant growth, fruit yield, yield components, light interception by plant canopy and nutrient use during August–January. Five levels of fertilizer (5–15g N per plant) were applied using CRF in a closed system and these were compared with plants given liquid fertilizer (LF) with an electrical conductivity (EC) control in an open system. The CRF was supplied in a water recirculation tank. Total N supply in the LF system (19.7g N per plant) was higher than in the CRF treatments. In the latter, fresh fruit yield increased with higher fertilizer levels up to 12.5g N. The fruit yields at 12.5 and 15.0g N were similar to those with the LF system. The high fresh fruit yield was caused by high dry matter yield regardless of the CRF treatments, which showed similar dry matter distribution to fruit. A high correlation was noted between cumulative light interception and total dry matter production. Although both were high, dry matter distribution to fruit was lower in the LF system than in the CRF treatments. Overall, however, these effects resulted in similar dry and fresh fruit yields between CRF and LF treatments, with excessive vegetative growth in the LF system. We conclude that the closed CRF application system reduced 37% of nutrient use but still gave a fruit yield equivalent to that obtained by culturing with the open LF system and EC-based management.