How to control the accuracy of seeding depth and seeding spacing using rice seeder

In modern agricultural production, the quality of rice sowing directly determines the uniformity of crop emergence, population structure and final yield. Seed depth and seed spacing are two key technical parameters for evaluating sowing quality. Seed depth is related to the contact state between seeds and water, temperature and air, while seed spacing affects the competitive relationship and nutrient distribution of plants. As the core equipment for implementing efficient sowing operations, the control accuracy of these two parameters of Rice Seeder reflects the comprehensive technical level of the equipment.

Principle and implementation of sowing depth control
1. Structural design of depth limiting device
Rice seeders are usually equipped with adjustable depth limiting wheels, compaction wheels or depth limiting slides. These devices run in close contact with the ground to maintain a constant distance between the sowing unit and the ground, ensuring that the seed falling depth is within the set range. The matching of the depth limiting wheel diameter and the elastic structure directly affects the depth consistency.
2. Type of sowing furrow opener
Different types of furrow openers (such as double disc type, concave type, pointed shovel type) have a significant impact on sowing depth. Double disc furrow openers are suitable for wet nursery fields or conditions with more weeds. They have strong ground adaptability and stable furrowing depth control capabilities.
3. Ground wheel drive and linkage control
Some mid-to-high-end seeders use ground wheel drive, and the depth of the seeding unit is automatically adjusted by the ground wheel feedback control system. As the terrain rises and falls, the seeding depth can be fine-tuned through the linkage arm and the hydraulic system to reduce the depth fluctuation caused by uneven soil.
4. Electronic monitoring and feedback adjustment
High-precision seeders are equipped with seeding depth sensors to monitor the changes in furrowing depth in real time and feedback to the main control system. The position of the depth limiter is quickly adjusted through an electric actuator or hydraulic device to achieve closed-loop control of the seeding depth.

Principles and technical points of seeding spacing control
1. Matching seeding speed and seeding frequency
The core of seeding spacing control lies in the precise matching between the forward speed of the seeding machine and the seeding frequency of the seeding device. The rotation speed of the ground wheel is transmitted to the seeding shaft through the transmission system to achieve synchronous adjustment of speed and seeding spacing. The faster the speed, the higher the seeding frequency, and the more stable the plant spacing can be maintained.
2. Precision seeding mechanism design
Currently, mainstream rice seeders mostly use air-suction, mechanical, pointer-type and other precision seeding devices. The air-suction seeding device uses a vacuum suction cup to accurately absorb a single seed, and achieves accurate seeding by controlling the rotation rate and the position of the seed hole; the mechanical tooth or drum seeding device relies on the physical grain separation structure for metering, releasing one seed or one hole of equal amount of seeds each time.
3. Linkage transmission ratio adjustment system
The seeding device and the ground wheel usually form a linkage system through gears or sprockets. The operator can replace the gear pair, adjust the transmission ratio, and change the number of seedings per unit distance, thereby accurately controlling the seeding spacing. Some seeders are also equipped with a stepless speed change device, which can continuously adjust the seeding density without changing the gears.
4. Intelligent calibration of the electronic control system
The advanced Rice Seeder adopts an electronically controlled seeding system, which realizes precise control of the number and interval of seeding through the joint work of position encoders, seed sensors and stepper motors. The system automatically adjusts the seeding frequency according to GPS positioning and operating speed to avoid plant spacing deviation due to speed changes.

Impact and response of external factors on control accuracy
1. Terrain and soil conditions
Uneven terrain, soil caking or excessive moisture content will cause fluctuations in sowing depth and affect the uniformity of seedling emergence. To this end, high-end seeders use suspension buffer structures and automatic pressure compensation systems to effectively reduce terrain interference.
2. Operation speed fluctuations
Sudden changes in forward speed will affect the consistency of sowing spacing. Some smart seeders integrate speed sensors and GPS navigation systems to achieve dynamic compensation by synchronously adjusting the seeding rate.
3. Different seed morphology
Different batches of seeds have different particle sizes, densities, and surface morphologies, which will affect the adsorption or granulation effects. High-precision seeders deal with seed variation problems through seed pretreatment, graded screening, or adaptive adsorption adjustment mechanisms.