Abstract:
The traditional orchard fertilization scheme is the sequence of trenching, fertilization and covering soil. In the process of orchard planting and management, trenching deeply is a key link, which has a great impact on the yield of orchard as well as the sweetness and quality of the orchard fruit. However, at present, orchard trenching and fertilization machine has a series of problems, such as great cultivation resistance, high power consumption and uneven mixing fertilizer, and there is a great need to develop a new kind of fertilization machine. So a double-helix fertilization machine named 1KS60-35X was designed, which used the front axle to break the ground while used the rear axle to mix the soil and fertilizer. The resistance torque equation of the rotary shaft used for breaking and mixing the soil was established, which could be used to quantitatively analyze the effect of screw blade parameters on tillage resistance. Furthermore, on the basis of the research on the parametric equation of spiral cutting edge, as well as by means of experience and theory calculation, the helical blade parameters of ground soil fertilization shaft were determined. Then the 3D (three- dimensional) parametric models of the cutter shaft and the whole machine were established using Pro/E. On this foundation, the prototype of a double-helix fertilization machine was completed. Afterwards, a series of trenching and fertilization field experiments were carried out, and the results showed that the ditching depth of this machine could achieve from 472 to 510 mm, and meanwhile the average depth could reach 496 mm and the average soil pushing height could attain 120 mm. In addition, the planting depth stability coefficient could achieve 98.2% and the planting width consistency could reach 99.2%. The soil aggregate diameters were mostly between 3 and 6 mm; the soil aggregate diameter in the whole soil and 100 mm surface soil ranged from 5 to 40 mm, while those from the sampling results were 6.75 and 6.86 mm, respectively. So the qualified rates of broken soil were 98.7% and 97.9%, respectively. The situation of granular fertilizer accumulation occurred less by using this machine, the vertical and horizontal distances of the centers of gravities were 16.24 and 15.53 mm, respectively, and the fertilization performance of each soil layer was relatively stable. This new designed machine abandoned the traditional operation mode of first trenching, then fertilization, and then covering the soil, while adopted the new operation mode that trenching, fertilization and covering the soil were carried out at the same time. So the number of operations could be effectively reduced. Therefore, with this new machine, the fertilization can be uniform and reduce the waste of fertilizer. What’s more, it can improve the soil structure and promote the root system of the fruit trees, which is beneficial to fruit growth. This new designed machine not only meets the agronomic requirements of orchard fertilization, but also provides a reference for the trenching and fertilization operation in mulberry field and tea garden.