Improved premixing in-line injection system for variable-rate orchard sprayers with Arduino Platform

Authors: ZHANG, ZHIHONG - Kunming University Of Science And Technology; Zhu, Heping; GULER, HUSEYIN - Ege University; SHEN, YUE - Jiangsu University

Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2019
Publication Date: 6/10/2019
Publication URL: https://handle.nal.usda.gov/10113/6379491
Citation: Zhang, Z., Zhu, H., Guler, H., Shen, Y. 2019. Improved premixing in-line injection system for variable-rate orchard sprayers with Arduino Platform. Computers and Electronics in Agriculture. 162:389-396. https://doi.org/10.1016/j.compag.2019.04.023.
DOI: https://doi.org/10.1016/j.compag.2019.04.023

Interpretive Summary: Pesticides have been progressively used to protect crops in the world agriculture to ensure high productivity and quality supply of food. However, there is an unsolved problem associated with conventional and precision variable-rate spray technologies: disposal of excess spray mixture and washed water. Sprayer operators must dispose whatever the amount of spray mixture is left in the tank and the washed water used to clean the tanks after applications. In this research, an improved experimental premixing in-line injection system was developed based on our previous prototype to solve the tank mixture leftover disposal problem. In the new system, water and chemical concentrates were stored separately in two different tanks. During spray application, the system automatically mixed desired amounts of water and chemical concentrates as the sprayer needed in real time. In this way, applicators could save the unused chemical concentrates for future applications. The new system gained more accessibility, stability, cost efficiency, and fluid metering accuracy by using a digital circuit board as a development platform. The system was also tested for its automatic fluid control functions under laboratory conditions. Future application of this new technology would further reduce pesticide waste and improve environmental stewardship for conventional and precision variable-rate sprayers.

Technical Abstract: To reduce the tank mixture leftover problem associated with variable-rate orchard sprayers, an experimental automatic premixing in-line injection system was developed with Arduino platform. This system primarily consisted of a precision fluid metering pump, a water pump, a static mixer, a premixing tank and a buffer tank. The required amounts of water and chemical concentrates were accurately pumped into the premixing tank through a static mixer. The mixture was then transferred into a buffer tank for additional mixing process and then for the spray pump to discharge to variable flow-rate nozzles. When the buffer tank neared empty, this process was repeated automatically. Accuracy of the metering pump was tested with simulated pesticides (tap water, turpentine oil, prime oil, and four concentrations of sucrose solutions) with viscosities between 0.9 and 32.0 mPa·s. By using fluorescent tracer method, the sucrose solutions were also used to evaluate the uniformity of spray mixtures discharged from the premixing in-line injection system. The test results demonstrated that the fluid metering pump could accurately dispense desired volume (10 - 300 mL) of simulated pesticides at different pump rotational speeds, and the relative errors between measured and desired volumes were below 5%. The premixing in-line injection system also provided consistent uniformity of spray mixtures at different desired concentrations (0.1% - 2%), and the highest relative error and coefficient of variation were 7.6% and 4.5%, respectively. Performance of the experimental premixing in-line injection system was stable and accurate, and had great potentials to improve spray application efficiency with minimized tank mixture leftovers for future variable-rate sprayers.