Development and test of automatic corn seedling transplanter

Abstract: Corn paper pot seedling transplanting technology is a new type cultivation method that can effectively increase accumulated temperature, resist drought, prevent disasters and obtain high yields; issues such as low and unstable grain yield due to shortage of water resources, drought and frequent plant diseases and insect pests in spring dry farming conditions. Conventional corn paper pot seedling transplanting operations are conducted on a manual basis, which generates features such as large labor intensity, low working efficiency, poor working quality, low degree of standardization and farming seasons cannot be grasped and so forth; the conventional operations are not beneficial to large area production operation, which seriously restricts the promotion and application of corn paper pot seedling transplanting technology. Therefore, mechanized corn seedling transplanting is an imperative trend.At present, corn paper pot seedling transplanting technology and methods as well as relevant machinery equipment are not available. Existing transplanting machineries in Europe, US, Japan and South Korea are mainly used for flowers, vegetables and economic crops. As per planting methods, transplanting machineries can be divided into: clamp type transplanters, chain clamp type transplanters, hanging cup type transplanters, seedling-guiding tube type transplanters and flexible disc type transplanters. However, all of such transplanters have some defects that cannot be overcome. A new type of full-automatic paper pot corn seedling transplanter was researched and developed based on the research of integrating the advantages of pot seedling and bare-rooted seedling, the principle of flexible disc type transplanting in combination with automation control and hydraulically powered seedling collecting, seedling rejecting and seedling supplying mechanism.The transplanter is composed of a seedling transporting and selecting transmission case, an automatic seeding system, a transplanting unit, a rack and an earthing and watering part. The seedling transporting and selecting transmission mechanism can automatically eliminate paper pots without seedlings or those with weak seedlings and accelerate seedling supplying so as to guarantee the uniformity of seedlings. The rapid automatic seeding device can realize functions such as automatic grabbing, separation and stacking of paper pot seedlings as well as automatic feeding of seedling disc. The function of the transplanting unit is to ditch, erect seedlings and perform transplanting. The earthing and watering part can perform watering and earthing operation to the seedling ditch after transplanting. The driving force for the seedling transporting and selecting case and the transplanting unit is from the friction between the supporting roller and ground; the power for the automatic seeding system is from the hydraulic motor driven by the rear power output shaft of a tractor; the logical relationships for various working parts are driven by the PLC control module. The transplanter realizes full-automatic transplanting by using a full hydraulic power system and an automatic control system with PLC as its core module. The transplanter applies a three-point rear suspension and it is used in combination with roller tractors above 48kW. The transplanter can be used in both ridge planting and flat planting. The field test results showed that, when the advancing speed of a unit is 2.5-3.0 km/h and the theoretical row spacing is 22 cm, the qualified rate of transplanting depth is 87.5% and, the qualified rate of row spacing is 93.2% and the qualified rate of seedling verticality is 91.2%, which meets the agricultural requirements of corn paper pot seedling transplanting. The transplanter is a mechanized carrier of carrying out the new type agricultural technology of corn paper pot seedling transplanting, and it can enhance the standardization, mechanization and automation degree of corn paper pot seedling transplanting operations in an outstanding way.