Effect of the Flow Rate on Plant Growth and Flow Visualization of Nutrient Solution in Hydroponics

Abstract

In hydroponics, the flow pattern of nutrient solution in a cultivation container affects the growth of plants. Even if the flow rate of nutrient solution is the same between containers, the flow pattern may differ based on the size and shape of the containers. Therefore, the flow pattern cannot be comprehensively described by flow rate alone. In order to identify the relationship between plant growth, root morphology, nutrient uptake, and flow pattern, a hydroponic cultivation of Swiss chard was carried out. In addition, in order to describe the flow pattern in a specific cultivation container, hydroponic flow patterns were observed via flow field visualization using particle image velocimetry. As a result, with the increase in flow rate, it was found that a specific flow rate can form an ideal flow pattern for plant growth. Under this flow pattern, nutrient absorption is promoted and roots are elongated, thereby absorbing more nutrients and further promoting plant growth. However, when the flow rate exceeds the ideal value, plant growth is hindered. In summary, identifying the ideal nutrient solution flow pattern in hydroponics can facilitate better crop production.

Effect of Substrate Flow Rate on Nutrient Uptake and Use Efficiency in Hydroponically Grown Swiss Chard (Beta vulgaris L. ssp. cicla ‘Seiyou Shirokuki’)

“…As shown in Figure 1, in this study, we achieved a similar result to our previous research [9,12]. That is, in a certain range, with the increase in flow, the growth of plants is enhanced.…”

“…to ensure normal growth of crops [8]. The key difference between hydroponic culture and soil culture is that a cultivation substrate in hydroponics can flow, which implies that a change in flow rate may affect plant growth in a hydroponic culture [9].…”

“…Baiyin et al [9] performed hydroponic cultivation of the vegetable Swiss chard (Beta vulgaris L. ssp. cicla) under different flow rates (0, 2, 4, 6, and 8 L/min) in a natural light greenhouse.…”

Effect of Nutrient Solution Flow Rate on Hydroponic Plant Growth and Root Morphology

“…To investigate the coupling effect of flow and other environmental factors on plants is a future topic for us. Furthermore, concerning the plant characteristics, cultivation container shape and environmental characteristics, to put forward a comprehensive index not only including flow rate to guide ideal flow regulation is also a topic for us in the future [7].…”

“…Plant nutrients in the soil typically reach the root surface by root extension, mass flow, and diffusion [6]. In hydroponic cultivation, flowable nutrient solution cultivation substrates also allow nutrients to be transported to the root surfaces via turbulent diffusion [7], which transfers nutrient ions to the root surface by the irregular motion of fluid particles. Turbulent diffusion is affected by a container's flow rate, which determines the circulation and diffusion of nutrient ions in the container and the resulting nutrient uptake and plant growth.…”