Design of an Air Blowing Device Above Seedbed: The Effect of Air Disturbance on the Microenvironment and Growth of Tomato Seedlings

Abstract

<jats:p>In recent years, air circulation has been used in protected cultivation to improve the microenvironment around seedlings, which in turn enhances photosynthesis and seedling growth. However, a practical and precise air circulation device has not yet been reported, especially one for growing seedlings in a greenhouse. Considering the use of a seedbed in seedling cultivation, a blower that can move back and forth on the seedbed and accurately control the air velocity is designed. In this experiment, we take the nonblowing treatment as the control (CK); three air velocities (0.3, 0.6, and 0.9 m/s) were selected to investigate the effect of interval blowing on the microenvironment of the canopy, physiology of seedling growth, stomatal characteristics of leaves, and stem mechanics of tomato seedlings. The three air velocities were found to significantly reduce the canopy temperature by 0.44, 0.78, and 1.48 °C lower than the CK, respectively, and leaf temperature by 0.83, 1.57, and 2.27 °C lower than the CK, respectively, in cultivated seedlings during summer. The relative humidity of the tomato seedling canopy decreased by 2.7% to 7.0%. Compared with the CK, the plant height of tomato seedlings decreased by 13.54% and root dry mass, root-shoot ratio, and seedling quality index (SQI) increased by 34.63%, 21.43%, and 14.29%, respectively, at 0.6 m/s. In addition, mechanical indexes such as hardness and elasticity of the tomato seedling stem were higher under air disturbance than those of the CK. The best effect was seen in the treatment with the air velocity of 0.6 m/s, in which the hardness and elasticity of the stem base and the first node were significantly higher than that of the CK. In conclusion, air disturbance generated by the air blowing device we designed effectively improved the microenvironment around the plants, enhanced the physiological activity of the seedlings, and thereby promoted seedling growth.</jats:p>

Improving Tomato Productivity for Changing Climatic and Environmental Stress Conditions

“…A similar result was observed in the height of tomato seedlings by wind-blowing [68]. The authors also observed that the wind treatment of 0.6 m/s every 30 minute for 5-minute reduced tomato seedlings hardness and elastic modulus by about 25 and 24%, respectively.…”

Urban-Metabolic Farming Modules on Rooftops for Eco-Resilient Farmscape

“…Kitaya et al [12] reported that vertical downwards air currents with airspeeds higher than 0.3 m/s around the plants promoted the photosynthetic and transpiration rates in plants. Another study for the same plant, tomato seedlings, carried out by Li et al [33], suggested that the best effect was seen in the treatment with an air velocity of 0.6 m/s. For sweet potato leaves, Kitaya et al [11] observed that transpiration and net photosynthetic rates were almost constant at air current speeds of 0.3-1.0 m/s.…”

Characteristics of Plastic Greenhouse High-Temperature and High-Humidity Events and Their Impacts on Facility Tomatoes Growth

“…Indexes of stem diameter, stem height, and dry mass of seedlings are used to evaluate the health of plant. In previous studies, these indexes are integrated to construct a composite index to describe the plant health comprehensively (Liu et al, 2015;Li et al, 2020). Abscisic acid (ABA) is an endogenous hormone in plants, which has risen significantly under abiotic stress to regulate its physiological activities (Ng et al, 2014).…”