Abstract:
Abstract: Garlic is one of the most important cash crops which cultivated widely in China. An enormous number of farms in developed countries have wide planting area, and almost all harvested garlic are sent to deep processing. Thus, there is poor requirement of garlic seed scaly direction. The high-level mechanization and automation garlic planter has been used in production as early as 1960s. In contrast, garlic is grown mostly in hills and plains, such as Hebei, Jiangsu and Shandong. The garlic planting time is about 20 days, the agronomic requirement of garlic planting is "scaly bud is upward while root is downward, and erectly planting". In view of this special agronomic requirement, the artificial planting mode has been used in a long time, that is farmers insert garlic seed into soil in accordance with agronomic requirement and then covering soil by hands. This mode has obvious disadvantages of great labour intensity, low working efficiency and high employment cast. In addition, most foreign garlic planters are not usually suitable for use in China. Thus, an efficient precision garlic planter plays a crucial role to the development of garlic planter mechanization in China. However, the bottleneck of garlic planter research and development is how to conquer garlic seed directing technology. On the basis of this present situation, a number of universities and related scientific research institutions have carried out a series of studies and achieved periodic results. An automatic directing garlic planter was designed in this study. In terms of it, there are seed taking device, garlic seed directing device, inserted planting device and pneumatic control system, and so on. The structure of key components had been designed. A small caterpillar base plate was applied to chassis, which reduced effectively the degree of soil compaction and powered by a diesel engine. The seed taking device is composed of chain drive, seed taking spoon, chain plate and vibrating mechanism. Garlic seeds have appearance characteristics of slender scaly bud, wide tail and shape of a half moon. Based on overall dimension of garlic seeds, a seed taking spoon was designed with length as 35 mm, width as 25 mm and depth as 15 mm. The seed taking spoons were mounted on chain plate with mode of staggered arrangement in double-rows, the longitudinal space of adjacent 2 groups seed taking spoons is calculated as 228 mm. The garlic seed directing device includes 3 stages conical hopper, hopper pointed conical half top angle decreases gradually which used to assist garlic seed in adjusting postures. The best angle combination is designed by experiment as 45°, 40° and 30°. The inserted planting device includes duckbill inserted planting apparatus and reciprocating lifting apparatus. The pneumatic control system was used for realizing precise matching between chassis, seed taking device and garlic seed directing device. The main influence factors of seed taking effect and seed scaly bud directing effect were proved through experiment study. Seed taking experiment result showed that the rate of taking single seed was 93.50 %, taking multiple seeds was 2.30 %, and miss taking was 4.20 % when planter speed was 0.10 m/s. The seed directing experiment result showed the rate of seed scaly upward was 94.44 % when longitudinal space between adjacent 2 stages hoppers was 100 mm and time interval of hoppers opening was 0.4 s. Field test results showed that the rate of seed scaly upward, sowing multiple seeds and miss sowing were 89.2 %, 3.2 % and 2.0 %, respectively, the productivity scope of garlic planter was from 500 to 650 m2/h, and all indexes meet the standard requirement of garlic planting. The planter exhibited a great performance.