Growth and Yield of Tomato Plants as Influenced by Nutrient Application Rates with Quantitative Control in Closed Rockwool Cultivation

Abstract

We compared the effects of quantitative control in closed system versus electrical conductivity (EC)-based control in open system of nutrients on the growth and yield of tomatoes in rockwool cultivation. Quantitative control supplied all nutrients once a day based on criteria for three application rates (1.0 ×, 1.25 ×, and 1.5 × the standard). These criteria were previously developed in the deep flow technique (DFT) to estimate their nutrient requirements, which used the three-day average amount of water absorbed by tomato plants. We compared the quantitative control in a closed system with two EC treatments in an open system, in which we supplied nutrient solution at high and low EC ranges. The 1.0 × quantity standard reduced the nutrient supply to 30-37% of the levels used in the low-EC treatment. N, P, and K concentrations in the 1.0 × substrate solution remained low and stable for two months after transplanting. The 1.0 × treatment had 27% lower total leaf dry weight and 23% higher total fruit yield than the low-EC treatment. However, greatly reduced growth and nitrogen content of upper leaf and slightly lower soluble solids content in the fruits suggest that the 1.0 × standard might provide insufficient nutrients during late growth stages. Excessive nutrient supplies, which were much lower than the low-EC treatment, increased substrate salinity owing to the accumulation of nutrients during the latter half of the growth period in the 1.25 × and 1.5 × treatments. The stable EC and nutrient concentrations in the 1.0 × substrate solution over time suggest that the three-day adjustment interval would be short enough. The quantity criteria developed for the DFT system could generally be applied to long-term rockwool culture, but the optimum range of nutrient supply was found to be from 1.0 × to 1.25 × the DFT standard in the later growth stages.

Nutrient supply and fruit yields in tomato rockwool hydroponics under daily quantitative nutrient management: analysis and evaluation based on leaf area index

“…For the QNM treatments, plants were supplied with low (QNM-L) or high (QNM-H) daily amounts of nutrients at a given water uptake averaged over the previous 3 d (Fig. 1), both of which were determined as suitable for tomato rockwool hydroponics (Matsuda et al, 2010;Nakano et al, 2010). The nutrient supply for the two QNM treatments were controlled using the automatic QNM system with the QNM server and client controller prototypes (Otsuka Chemical Co., Ltd., Osaka, Japan) as described in detail in Matsuda et al (2010).…”

“…Quantitative nutrient management (QNM) was recently proposed for using inorganic nutrients efficiently in tomato (Terabayashi et al, 2004;Hosoi and Hosono, 2005;Nakano et al, 2006Nakano et al, , 2010 and spinach (Maruo et al, 2001) hydroponics. In QNM, the nutrient requirement amount of plants during a defined period (e.g., a day or a week) is predicted and set in advance.…”

NO3− Requirement and the Quantitative Management Method of Nutrient Solution Based on NO3− Supply in Hydroponic Culture of Radish Plants

“…Likewise, tomato plants were reported to be hydroponically grown by the QNM method with the daily supply of a small amount of nitrogen to regulate the leaf area index (LAI) at optimum (Hosoi and Hosono, 2005) and with the daily supply of nutrients according to the average amount of water absorbed daily during the previous three days (Nakano et al, 2010). Thus, daily or shorter interval supply of nutrients appears to be highly applicable to the long-term culture of tomato plants.…”

“…As an approach to an alternative method to conventional nutrient solution management, in which the levels of nutrients in nutrient solution are controlled to be maintained at optimum EC (EC-based control method) values, the quantitative nutrient management (QNM) method was proposed by several researchers in the hydroponic culture of tomatoes (Kageyama, 1991;Kidono and Suzuki, 2006;Nakano et al, 2006Nakano et al, , 2010Terabayashi et al, 1996), spinach (Maruo et al, 2001;Takei and Suzuki, 2013), melons (Pardossi et al, 2002), and chrysanthemums (Kageyama andKonishi, 1992, 1996;Kageyama et al, 1987Kageyama et al, , 1993Kageyama et al, , 1995Shima et al, 1995). In spinach plants, Maruo et al (2001) proposed a QNM method by from those of leaf vegetables such as spinach.…”

Responses of Leaf Photosynthesis, Plant Growth and Fruit Production to Periodic Alteration of Plant Density in Winter Produced Single-truss Tomatoes

“…1). A drip irrigation nutrient solution (Nakano et al, 2010) adjusted to 1.8 dS·m −1 EC was automatically supplied with a feeding rate of 100-120 mL per irrigation event per plant from 06:00 until 18:00. The EC of the nutrient solution was gradually increased from 1.8 to 6.5 dS·m −1 depending on plant growth and development.…”