Manufacutre and field testing of the pruning machine for grapevines

Abstract:【Objective】Grapevine pruning is an important part of vineyard management. It not only controls effectively the space configuration of the main arms and side canes, enhances the overall ventilation and transmittance of the orchard and helps the fruit growth and bearing, but also improves the fruit yield and quality, and affects directly the economic benefit. Research on pruning machinery started early in Europe, America and a few additional countries, and the machine models were also complete. The pruning machines have been combined with automation technology and artificial intelligence, and the working speed is faster and the efficiency is higher. Some models also have cane recovery equipment and combine with picking machinery. However, the development of pruning machinery started late in China and actually few models have been developed sofar. At present, most of the pruning machines are mainly hand-held, supplemented with electric and pneumatic pruning. At present, there are many problems in practical grapevine pruning, like large labor intensity and low working efficiency. To solve the problems, a new pruning machine is required to develop for improving the overall level of orchard mech-anization in Chinese grape production.【Methods】By application of mechanical design theory and methods, the grapevine pruning machine was developed, fully considering the characteristics of the standard cultivation models of Chinese vineyards and the technical requirements. The pruning machine took the crawler tractors as power, which was mainly composed of the hydraulic system and the pruning system.The hydraulic system was fixed to the rear of the crawler tractors by the suspension mechanism, and it was mainly composed of hydraulic oil tank, hydraulic pumps, electromagnetic reversing valves, hydraulic cylinders, hydraulic motors and so on. In order to ensure the pruning speed and work quality, the double pump was adopted and a hydraulic pump controlled separately the cutting motor to complete the pruning work. Gear pumps and gear motors were also selected. The pruning system was attached to the front of the crawler tractor and it was made up of cutter, cutter shaft, pulley, belts, protective cover and so on. The power was driven to the hydraulic system by the rear power output shaft of the crawler tractor and the universal drive shaft. The hydraulic oil was pressurized and divided to two ways by the double oil pumps.One way was that the hydraulic oil flowed to two regulating oil cylinders and the rotary motor to realize the adjustment of the lifting and folding and pruning angles of the arm. Another way was that the hydraulic oil was supplied directly to the cutting motor to drive the cutter. The grapevine pruning worked well for the three cultivation models of trellis, V-system and hedge. In the pruning system, the characteristics of the three kinds of cutters were compared, and the cutter type of the pruning machine was determined to be the rotary cutter. The rotation speed of the cutter was determined to be 2 700 r · min-1 and the size and number of the cutter were also determined. In the hydraulic system, the hydraulic system diagram was designed and the type of hydraulic motor and pump were determined. The field testings were conducted on September 11, 2016 and July 20, 2017 at the Grape Core Technology Experimental Demonstration Park of the Research Institute of Pomology, Chinese Academy of Agricultural Sciences. The testing conditions are as follows: the cultivation models of the grape include trellis, V-system and hedge, and the spacing of the V-system and trellis is 0.7 m´3.5 m, and the spacing of hedge is 0.7 m´4.0 m, and the working speed of the pruning machine is 1 m·s-1.【Results】The field test showed that the grapevine pruning machine was stable, adaptable and efficient, and the work efficiency of the machine was 30 times higher than that of the hand-pruning, and the pruning effect was also desirable.【Conclusion】The grapevine pruning machine was developed according to the standard cultivation models and pruning requirement of the grapevines in China to meet the demand of the industry. The development of the machine has laid the equipment foundation for the research on the simplified pruning and cultivation techniques of grapes, and showed a good prospect for popularization. Because the whole plant pruning method has to be adopted by the machine, it would cause damage to the leaves. Take care of spraying the fungicides in time and prevent from the disease after pruning. It might be suggested that the pruning machine needs to be upgraded in the aspects of automation and intelligence to improve the work efficiency in the further.