Design And Research On Key Components Of The Planter For Virus-free Mini-potato Seeds

Potato is the fourth largest food crop after maize, wheat and rice in the world. Developing potato industry is an effective way to ensure the total grain output in our country with ecological degradation, shrinking arable land area and other harsh environments in today’s society. China has become the world biggest country in term of potato production but not the potato industry great power. One reason causing that is people mainly plant potatoes with diced potatoes which are prone to virus infection as seeds; second is the low level of mechanization of potato production in our country. Along with the breakthrough of the research on potato seedling technique, high-quality virus-free mini-potato seed has gradually stepped into the commercialization in China, which means the matter of poor quality of seed potato in potato industry has been resolved. Existing potato planting machines at home and abroad are mostly with the whole or diced potatoes as sowing seeds and adopt mechanical type, causing seed potatoes infected with the virus easily, which will influence the quality and yield of potato. The paper designs a precision pneumatic metering device with declined disc which is lesser damage and breaks traditional seeding method for virus-free mini-potato seeds, and manufactures a planter could meet the growing agronomic requirements of virus-free mini-potato seeds. This design not only improve the working efficiency of potato planting, reduce the damage of seed potato, but also provide a new method for the high quality and high yield of potatoes.The research contents of this paper are as follows:(1) Design and manufacture of the planter for virus-free mini-potato seed. Based on the material characteristics and the growing agronomic requirements of the virus-free mini-potato seed, designed and manufactured a planter applied to wide-narrow row with single ridge cropping pattern. Partial design parameters of the machine were given. This planter consisted of frame, suspension system, pneumatic system, driving wheel, transmission system, fertilizing system, seed-metering system, double-wing ditcher, grading mechanism, etc. The machine went to the fields once could realize the works covered furrowing, fertilizing, seeding, covering and ridging.(2) Optimal design and experiment of the precision pneumatic metering device with declined disc.Optimized and designed a precision pneumatic metering device with declined disc for virus-free mini-potato seed. Combining performance test, structural analysis and optimization were carried out based on analyzing the influence factors of the metering device’s performance. A cleaning device was increased in order to remove the extra seed potato; the structure of the air chamber was changed, such as changed the right-angle of the air chamber to circular arc transition, installed seal ring around the air chamber, for ensuring the stability of air flow and enhancing the tightness of the air chamber; the seed chamber and the seed box’s structure were changed, so the shape, location and size of the inlet would be better for the seed potato entering into the seed chamber and keeping the balance of the seed potato flow in seed chamber.(3) Performance test of the precision pneumatic metering device with declined disc. Taking the eligible index, multiple index, miss index and coefficient of variation of the metering device as main evaluation indexes, and the rotational speed of metering shaft, tilt angle of metering disc and the shaped hole form of metering disc as experimental factors, single factor and orthogonal experiments were carried out. The influence rules of experimental factors on performance indexes were determined by single factor experiment; the orthogonal experiment was employed to study the optimal parameters of the metering device. Orthogonal experiment showed that when the rotational speed of metering shaft was10r/min, tilt angle of metering disc was45°, and the shaped hole form of metering disc was cylindrical hole with9×Φ12mm, the eligible index reached as high as97.62%, the miss index was0.67%, the multiple index was1.71%, and the coefficient of variation was8.94%, meeting the requirements of precision seeding.(4) Impact of the precision pneumatic metering device with declined disc on damage of virus-free mini-potato seed, and the germination experiment of damaged virus-free mini-potato seed.Through the experiment, observed the virus-free seed potato had two damage forms include the skin damage and the bud damage when it was sowing with bud, and confirmed that the damage rate of virus-free mini-potato seed was not remarkably influenced by the rotational speed of metering shaft, the tilt angle of metering disc and the shaped hole form of metering disc. The skin damage rate was still less than1%, and the bud damage rate was less than2%, even though the virus-free mini-potato seed was repeatedly used3times. And as long as there were eyes, the virus-free mini-potato seed would still germinate even if it was damaged. The germination experiment indicated that the longer the seed potato stayed in metering device, the more severe the damage. And the longer the bud, the higher the bud damage rate. Seedling emergence was faster and seedling growth was neater relatively for virus-free mini-potato seed when it was sowing after accelerating germination. The germination index and viability of the seed potato which was lesser damaged were better.