Sustainable Soilless Cultivation Mode: Cultivation Study on Droplet Settlement of Plant Roots under Ultrasonic Aeroponic Cultivation

Abstract

In order to solve the effects of environmental factors on the droplet settlement of a nutrient solution on plant roots when planting plants with ultrasonic aeroponic cultivation, this study aimed to obtain a suitable wind speed range and atomization time through a nutrient solution atomization experiment, to obtain the best control scheme through a multi-environmental parameter combination cultivation experiment. Taking an ultrasonic aeroponic cultivation device as the research object, and lettuce as the test material, experiments were carried out on two factors affecting the wind speed of an axial fan and the atomization time of the nutrient amount of ultrasonic aeroponic cultivation plants; the suitable wind speed range was 1.0–2.5 m/s. The temperatures of the lettuce root zones in the upper, middle, and lower layers of the ultrasonic aeroponic cultivation device at different time periods were obtained by atomizing the nutrient solution. When the optimum temperature for the root growth of lettuce was 15–20 °C and the wind speed was 1.0–2.5 m/s, the continuous atomization time of the nutrient solution was 66–184 min. Using a quadratic orthogonal rotation combination design method, three main factors, namely wind speed, ambient temperature, and atomization time, were selected to test droplet settlement in the lettuce roots. The droplet settlement in the lettuce root system was measured. The droplet settlement regression equation in the lettuce root system was established. The reliability of the regression model was tested according to the significance condition, and a simplified quadratic orthogonal regression equation was obtained. The main effect analysis, single factor analysis, and interaction effect analysis were used to analyze the model, and the model was further verified. The verification results showed that the relative error between the predicted value and the actual value of the average root droplet sedimentation was 5.8%. The optimum wind speed was 2.5 m/s, the ambient temperature was 16 °C, and the atomization time was 184 min when the ultrasonic aeroponic cultivation device designed in this study was used to cultivate lettuce. It could provide a theoretical reference and an experimental basis for the control of the related growth environment parameters of plants cultivated using ultrasonic aeroponic cultivation.

A Comprehensive Analysis of Technology in Aeroponics: Presenting the Adoption and Integration of Technology in Sustainable Agriculture Practices

“…Compared to conventional soil-based agriculture, aeroponics has a number of benefits, such as quicker growth rates, greater crop yields, and more economical resource utilisation [7,8]. A more environmentally responsible and sustainable method of farming is made possible by the soil-free environment's ability to lower the risk of soil-borne illnesses and pests [9]. However, expensive initial setup costs, maintenance requirements, and a high level of technical competence required are its key problems [10].…”

Review of the design of power ultrasonic generator for piezoelectric transducer

“…Among them, the ultrasonic cavitation effect can cause a series of secondary effects by collapsing cavitation bubbles, which generally results in the phenomena of micro-eddy current, micro jet, shockwaves, local high temperature and high pressure [10] , [26] , [27] , [28] . So based on these effects, the PUT has been widely utilized in many industrial fields, such as in the ultrasonic cleaning and atomization field which is mainly applied to the cleaning and sterilization of medical equipment [8] , [29] , anti-scaling and descaling [30] , [31] , [32] , wastewater treatment [33] , microbial inactivation [8] , agricultural aerosol cultivation [34] , atomization drug delivery [35] , paint spraying [6] , [36] , spherical metal powder manufacturing [37] , liquid drop levitation [38] , and the cleaning of large-scale integrated circuits, optical devices, silicon chips, and other sub-micron particle products [39] . Furthermore, it has been extended to the fields of ultrasonic dust removal by agglomerating smoke particles [40] , ultrasonic drying by accelerating the evaporation of water molecules [41] , ultrasonic extraction by auxiliary chemical analysis [42] , [43] , [44] , [45] , and ultrasonic defoaming of industrial coatings or beverage production [6] , [46] .…”

Systematic Review of Technology in Aeroponics: Introducing the Technology Adoption and Integration in Sustainable Agriculture Model

“…Aeroponics offers several advantages over traditional soil-based agriculture, including faster growth rates, higher crop yields, and more efficient use of resources [7,8]. The soilfree environment also reduces the risk of soil-borne diseases and pests, allowing for a more sustainable and environmentally friendly approach to agriculture [9]. On the other hand, its main challenges are high initial setup costs, maintenance requirements, and a high level of technical expertise requirements [10].…”

“…This results in improved nutrient absorption, root development, and photosynthesis efficiency, all of which contribute to larger products. Yang et al [9] implemented an ultrasonic aeroponic system to improve lettuce size. Using a smart dispenser system, the researchers managed to control the wind speed, the ambient temperature, and the atomization time, three determining factors for the product size.…”