Variation of root-zone droplet deposition, temperature and humidity of truss ultrasonic atomization cultivator

Abstract: Temperature and humidity in root zone were crucial even vital factors that influence aeroponic efficiency of truss ultrasonic atomization cultivator. A real time acquisition system of temperature and humidity based on Labview with data acquisition card NI PCI-6110 and a spray control system with micro computer unit PIC16F877A were developed. How these factors of the wind outlet area, temperature in truss tube, atomization rate and spray time influenced the deposition of spraying droplets, temperature and humidity in cultivation pipes of truss ultrasonic atomization cultivator were investigated. Quadratic regression rotation combination orthogonality experiment design of four factors and five levels was adopted to study quadratic regression model of deposition of spraying droplets, temperature and humidity. According to regression equations of temperature and humidity of upper and lower layer pipeline, when the wind outlet area was 1174, 2205 and 2640 mm2, respectively, the corresponding spray time was 6.3, 5.9, 7.1h, indoor temperature 25 ℃, corresponding atomization rate one, two and three, the temperature of prediction 25 ℃, and humidity was 100%. And the corresponding temperature which we measured was 24.16, 24.25, 24.08 ℃, and corresponding humidity was 98.96%, 98.58%, 99.23%, respectively. All control relative errors were less than 5%. Therefore, these regression equations could be used to predict the temperature and humidity of this type of ultrasonic atomization cultivator and be applied to the optimal control of temperature and humidity of plant root zone of this type of ultrasonic atomization cultivator. The results showed that the interaction of spray time, atomization rate, the wind outlet area and temperature had significant influence on the deposition of spraying droplets of upper and lower layer pipeline. The wind outlet area, temperature, atomization rate and spray time had significant influence on the temperature of upper and lower layer pipeline. The interaction of the wind outlet area and temperature had significant influence on the temperature of upper layer pipeline. The wind outlet area, temperature and spray time had significant influence on the humidity of upper and lower layer pipeline. This research provides experimental references for optimal controlling of truss ultrasonic atomization cultivator.