In order to improve the utilization rate of corn straw, the 4JQH-120 straw collection machine was taken as the research object. Three kinds of pickers that can work with it were designed by selecting different tools and arrangements. All pickers used “Y” shaped knives and adopted the double helix arrangement. The first type of picker consisted solely of “Y”shaped knives, while the second type combined hammer claws and “Y”shaped knives in a mixed arrangement. The third type of picker featured a symmetrical mixture of hammer claws and “Y”shaped knives. Through the modal analysis of the three pickers using ANSYS, the natural frequency of the lowest order was determined to be 186.09 Hz, which was not within the design frequency of 31.67-38.33 Hz and did not resonate. The three factors of picker type, picker speed, and travel speed were selected, and the threefactor and threelevel orthogonal experimental design was carried out. EDEMRecurDyn was used to jointly simulate the pickup device part to clarify the mechanism of straw being picked up and broken. The simulation results showed that no stress deformation occurred in any of the pickers. Equipped with a DC picker, the straw picking rate was the highest at a speed of 2 300 r/min and a travel speed of 0.6 m/s, achieving a rate of 81.85%.This study can provide reference for the optimization of corn straw collector and other crop pickers.

corn straw returning technology; underground irrigation; straw; soil; corn straw composite tube; total returning

 In the field operation of the planter in the clean wheat area of the whole straw stubble field, the quality of straw mulching cannot be guaranteed due to the mismatch between the straw delivery rate and the speed of the uniform scatters device, resulting in problems such as low seedling emergence rate and poor seedling uniformity. Aiming to solve this problem, a set of strawspreading automatic control systems was designed. The system used STM32 singlechip microcomputer as the main control unit, used the phase difference torque detection device to collect the torque of the cutter roller shaft, and realized the adaptive adjustment of the speed of uniform scatters device through the indirect detection of the straw delivery rate. In order to verify the effect of the system, the cutter roller shaft spined at a top speed of 2 200 r/min, and the tractor was running at five common speeds, which were 0.9 m/s, 1.0 m/s, 1.1 m/s, 1.2 m/s, 1.3 m/s, respectively. A comparative test was carried out with or without the automatic control system of straw scattering and covering. In this experiment, without an automatic control system, the uniform scatters device rotated at 800 r/min. In contrast, the rotation speed of the uniform scatters device was automatically adjusted with the system, and the adjustment range was 600-1 200 r/min. The test results indicated that, in the same working conditions, after using the automatic control system for straw scattering and covering, the unevenness of straw spreading can be maintained below 15%, which improves the operational performance of the machine.

With the implementation of the strategy to make potato a staple food, the potato industry receives more attention in China. Combined harvest is an important part of potato production, and the key to potato harvest quality is separation of potato and soil. In order to further understand and master the research status of separation technology of potato and soil at home and abroad, the study was overviewed and analyzed. In the paper, the principle and structure of several different separation technologies such as vibration separation with rod, vibrationswing combined separation, poking roller shoving separation and rotary separation were expounded. Besides, the secondary separation form of potato and soil in combined harvest was analyzed. The application of potato and soil separation device in current combined harvest was introduced. It confirmed that the main problem of potato combined harvest was the contradiction between separation effect and damage rate. The mentality of design of the separation of potato and soil from different soil types and planting areas was analyzed, and three respects e.i. intelligence, compound, greening were prospected for the future, so as to provide some reference for scholars engaged in related research.

Grain production in Jiangsu Province was dominated by rice-wheat rotation, and stubble connection was especially tight, so the requirements of mechanized sowing equipment for wheat after rice were also increasing. Based on the introduction of the seeding methods of wheat after rice in Jiangsu Province, this paper described the general situation of five types of wheat after rice mechanized seeding technology in Jiangsu Province. There were some existing problems in mechanized sowing of wheat after rice in Jiangsu, such as large amount of full straw returning to the field, high cost of comprehensive utilization after removing the straw from the field, difficulty in sowing wheat in wet and bad fields, high production cost of mechanized sowing, and difficulty in subsidizing new products. Measures and suggestions were put forward, such as strengthening the integration of agricultural machinery and agronomy according to local conditions, vigorously promoting land circulation, moderately developing large-scale and intensive management, and accelerating the research and development of new mechanized sowing machines and tools for wheat after rice in Jiang.