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.

In response to the requirements of the development of green and sustainable agriculture, the strip tillage has been popularized and applied in rice and wheat planting areas in southern China. In order to simplify the effect of tillage components on the quality of strip tillage, field experiments were carried out on chisel blade, straight blade and IT225 blade at 280, 380 and 510 r/min. The results show that the main factors affecting the tillage quality are the shape of the blade and the rotary speed. When the rotary speed is 510 r/min, the soil backfill rate created by IT225 blade is only 7%, and the backfilling effect is significantly lower than that of the straight blade and chisel blade with small tangent edge. Chisel blade can achieve better backfill and soil crushing effects, but it is unable to create a neat seedbed section due to the lack of side cutting edge. When the rotary speed is 180 r/min, the crosssection disturbance rate of the seed bed of the chisel blade is as high as 20%. The straight blade can form a neat crosssection of the seed bed and a soil backfill rate higher than 50%, but the particle size of the broken soil is too large to meet the needs of sowing. This study points out the direction for the optimization of belt rotary tillage components, that is, taking into account the characteristics of straight blade rotary tillage knife and chisel rotary tillage knife, and organically combining two or several knives to meet the needs of belt rotary tillage and seeding under different soil conditions.

 This paper analyzed the development of mechanization of 8 main cash crops such as cotton, oil, sugar, vegetables, orchard, tea and herbal medicine in China by region, industry, variety and link, and put forward the main direction and technology for the present and future period. The result showed that compared with 2020, the comprehensive mechanization rate of cotton, rape, peanut, sugarcane, vegetables, tea and herbal medicines will increase by 2.7 percentage points, 3.4 percentage points, 3.6 percentage points, 1.9 percentage points, 4 percentage points, 1.8 percentage points and 2.5 percentage points respectively in 2021, only orchard increases by less than 1 percentage point. The main issues that need to be focused on are over 1 000 khm2 cotton, 1 000 khm2sugarcane, 1 800 khm2 peanut cannot be harvested by machine in China, over 4 200 khm2 winter fallow field need to be planted rapeseed, mechanization of vegetable, orchard, tea garden, herbal medicine are very low, no machine to use, machine cannot be used efficiently, field conditions in Southern China and hilly areas and traditional planting modes are not suitable for machinery, the work qualities and reliabilities of domestic machines need to be advanced, plastic film residue in peanut and cotton planting. The main push technologies include advancing domestic machines quality, high efficient plastic film residue reclamations, rape machinery suitable varities selection and combined working, summer peanut no film planting and high efficient harvesting, sugarcane low impurity harvesting and sugar making process reforming, typical vegetable standardized planting and high efficient harvesting, orchard and tea garden machinery suitable construction and management by standard, major herbal medicine varieties mechanized production in customization and so on.

To further investigate the operation mechanism and improve the cutting quality of the root profiling floating cutting mechanism, the kinematic characteristics of the profiling floating operation process of the cutting mechanism were analyzed in this paper. Mathematical model of the floating displacement of the cutting mechanism, rotary cutter blades trajectory surface, and cutter blades cutting speed were measured. The influences of the structure and kinematic parameters of the rootcutting mechanism on profiling floating cutting were explored. Simultaneously, the cutter motion trajectory curve, timecutting speed curve, and displacementcutting speed curve were obtained using the ADAMS virtual prototype simulation test. Also, the influences of cutter rotational speed, cutter quantity, cutter blade position and displacement on cutting times, missed cutting area, cutter motion trajectory, and cutting speed were analyzed. The research results show that by setting the structure and kinematic parameters of the root cutting mechanism reasonably, the profiling floating cutting operation of the machine can be effectively realized, and the root cutting operation effect can be improved. When the conveying speed was 1 m/s, the cutter angle was 33°, and the rotational speed of the cutter was 2 600 r/min. The number of root cuts could reach 2 times by the rotated highest point of single cutting edge, and the missing cutting area was minimal. When the conveying speed was 1 m/s, the cutter angle was 33°, the rotational speed of the cutter was 1 000 r/min, and the cutter quantity was 4 pieces. The number of root cuts could reach 2 times by the rotated highest point of all cutting edges, and the missing cutting area was minimal. This study can serve as a theoretical foundation for future research on the operation mechanism and mechanism optimization of the root profiling floating cutting mechanism of garlic combined harvester.

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.