| The development of variable rate fertilizer applicator is significantly improving the utilization of chemical fertilizer. Through implementation of variable fertilization according to different status, the variable method could reduce the problems of environmental pollution, which also has the positive economic benefits for agricultural production cost. Therefore, the variable rate fertilization technology become the focus research field of farm machinery and equipment all over the world. Many foreign companies on the variable fertilization system implements navigation, operation records, mapping, variable control, soil sampling and other functions. Our country in the field started late. However, variable rate fertilizer prescription proportion of fertilizer application and other fields have achieved many results. But the key technology is mainly rely on the purchase of imported complete sets with GPS products and machinery, which lead our in the passive development stage.This study expects to develop variable rate fertilizer applicator to implement variable rate fertilization, which could improve the utilization rate for the purpose of liquid fertilizer system; according to research status and trend of variable fertilization system development at home and abroad, this study separates the system into three parts. There are prescription generates, variable fertilization device and variable fertilization control system, and fertilizer monitoring system; The prescription generation is the basis of this study. The variable fertilization device and control system is the main content of this study. The seed-fertilizer monitor system is the feedback stage of this study. These three parts are the overall of my study.This study had analysis a large number of theories and examples of prescription generation algorithms home and abroad and compared currently widely used prescription map generation methods. The paper emphasis on soil sampling method, Kriging interpolation, and prescription generation method based on GIS and BP neural network through "nutrient-density-output" data. Furthermore, the paper probed accumulation regularity of dry biomass in crop growth process to explore the optimization of slow-release fertilizer delivery and at the second fertilizer fertilization strategy, which finally established the soil fertilization and aim yield variable fertilizer controlling model.The paper according to the development of variable liquid fertilizer technology at home and abroad, put forward four variable liquid fertilizer device design approaches. There were hydraulic system, electric variable pressure valve, vehicle power and fertilizing based on adjustable precision control system. Through the mechanism of four kinds of scheme comparison research, the paper combining with the programming implementation difficulty, chose the former two approaches to implement the variable control. And detailedly design the control system’s hardware, software, sTab. performance and test optimization. Then design experiments to analysis the performance of every device, including two factors five levels quadratic regression orthogonal rotary center combinatorial optimization experiment and single factor optimization. Finally, the paper applied Design-expert6.0.10to analysis the significant level by regression equation.By comparing the detection methods of fertiliing devices at home and abroad, this paper adopted the photoelectric sensing technology, high brightness leds with red and photosensitive resistance as the research object, and mini2440development board as the master control platform, based on51single-chip signal acquisition platform, design of photosensitive type seed manure monitoring devices, realize the precise sowing machinery job status real-time monitoring. Test showed that under the different working environment, operation speed, the monitor system could display good anti-dust capability and working performance. |
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