| Kiwi is a dioecious plant,improving its pollination effect is the key factor and premise to ensure kiwifruit quality and its yield.Kiwi flower pollination mainly relies on manual operation in China,with low pollen utilization rate,high labor intensity and cost,which restricts the rapid development of kiwifruit industry.Air-liquid atomization has the characteristics of uniform particle size,stable atomization effect,air-liquid separation control and strong targeting,which can meet the requirements of high speed,low loss and precision of kiwi pollination.The development of air-liquid pollination equipment for kiwi flower has broad application prospect and important economic value.In this thesis,research of air-liquid spray pollination parameters and the design of pollination equipment were carried out on the "Hayward" kiwifruit growing under the scaffolding cultivation mode.The main research contents are as follows:(1)quantitative study on agronomic parameters of mechanized pollination operation.The structure characteristics of the kiwi flower was measured and analyzed in the thesis,then the air-liquid spray pollination model for kiwi flower was proposed,the pollen gains qualities demand of sufficient pollination was calculated.The results show that the kiwi flowers is160～190 cm from the ground.The kiwi flower were distributed in clusters,the clusters consisting of 4 flowers is the largest proportion of 33 %.At the horizontal surface,the average length and width of 97 % clusters are less than 13.35 cm and 9.87 cm respectively.With mass fraction 0.1 % pollen deposition,the pistil of a single kiwi flower needs to deposit at least42.9 mg of pollen suspension to ensure full pollination.(2)Study on the spray control parameters of pollination deposition with air-liquid nozzle.According to the structure parameters of kiwi flower blossoms and the demand for fully pollination,a air-liquid spray pollination control test device was constructed.The methods of deposition weighing,image grayscale analysis and laser measurement of droplet size were used to measure the droplet deposition,droplet coverage and droplet size in the blossoms center.The results show that the air-liquid spray operation parameters,air pressure of 0.20 MPa,pollen liquid flow rates of 0.125 L/min,spray pulse duration 0.1 s,and spray distance of35 cm,which can improve effective deposition of pollen liquid in the stigma of blossoms.(3)Design and manufacture of kiwi flower air-liquid spray pollinator and its control system.According to the operation parameters of air-liquid spray pollination and Chinese kiwi planting standards,the whole structure were designed,including of liquid pipelinesystem,air pipeline system and power system of kiwi flower spray pollinator.design of pollen suspension fluid flow rate and spray air pressure control system,and the kiwi flower blossom on the target control system was conducted.Control systems use water flow sensors and air pressure sensors to detect liquid pipes flow and pressure of air pipes,and uses Pixy camera to recognize and locate space coordination of kiwi flowers.(4)Taking Kiwi flower pollination experiment in the kiwi orchard.Firstly,according to the spray control parameters of kiwifruit pollination,a continuous spray pollination experiment of kiwi flower was conducted in the kiwi orchard.The effects of pollen fluid flow rate,spray air pressure and movement velocity of pollinator on the kiwi flower pollination effect were studied by taking kiwi flower fruit-setting rate,fruit weight and fruit deformity rate as the experimental indexes.Secondly,the targeted pollination test was carried out with the optimized air-liquid spray parameters to verify the these parameters pollination effectiveness.The results show that the effect of spray air pressure,movement velocity of pollinator and pollen suspension fluid flow rate on fruit setting rate declines successively.The effect of movement velocity of pollination on fruit deformities was the most significant and the spray air pressure was the least.When the optimized spray parameters were used for targeted kiwi flower pollination,the fruit-setting rate of air-liquid spray pollination was86.7 %,which was 6.7 % higher than that of hand-held spray pollinator,13.4 % higher than that of electric spray pollinator,and 5 % lower than that of point to point pollination by hand.The experiment shows that the effect of air-liquid spray pollination is better than that of electric sprayer and hand-held sprayer,and worse than that of point-point pollination by hand,but the work efficiency of air-liquid spray pollination is higher than that of point-point pollination by hand. |
