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Mechanical interaction between a canopy opener and rice stalks based on the transient dynamic analysis

Wu, Shu, Wei, Xinhua
Biosystems engineering 2019 v.178 pp. 256-263
Fulgoroidea, Oryza sativa, canopy, insect pests, leaf blight, nozzles, pesticides, rice, simulation models, sprayers, spraying, China
Rice planthoppers and rice sheath blight are the main insect pest and the main disease found on rice in China. Both occur in the middle and lower sections of the rice canopy. Pesticides are widely applied to prevent economic losses but most spray is retained by the upper canopy of the crop. Spray may penetrate the dense crop canopy but only a small fraction reaches the middle and lower levels of the canopy. In order to improve the penetration of spray into the lower canopy, a mechanical canopy opener was attached to a boom sprayer. The canopy opener consisted of the conduit pipe mounted on the spray boom in front of the nozzles. However, there should be an optimum placement of the device to produce the best spray penetration and coverage whilst causing a minimum damage to the crop. The objective of this work was to analyse the time-dependent displacement of rice plants and establish a mathematical relationship between time and displacement under the different positions of canopy opener. In order to establish a simulation model of the rice plant, experiments to determine the relevant parameters were carried out. Simulation parameters were determined by combining test results and calculations. Rice plant displacement over time, under the action of the canopy opener, was obtained by transient dynamic simulation. Simulation results were verified by high-speed-photography tests. Following analysis, the best canopy opener position based on the largest displacement of the rice plant was obtained.