Detailed Explanation of Key Points of Peanut Production Mechanization Technology

I. Technology Introduction
1. Technology Overview
Peanut production mechanization technology refers to the use of machinery to complete the agronomic processes of peanut production, mainly including mechanized technologies for land preparation and tillage, sowing, film mulching, fertilization, field management, harvesting, pod picking, shelling, etc.
2. Production Demand and Application Status
China has a long history of peanut cultivation. After the founding of the People's Republic of China, peanut production developed rapidly. Especially in recent years, with the continuous development of agricultural technology, peanut yield per unit area, total output and exports have all ranked first among the world's major peanut-producing countries in the same period. In 2000, China's total peanut planting area reached more than 4 million hectares, with a yield per unit area approaching 3,000 kg/hectare, and total peanut output reached 12 million tons, accounting for about 30% of the world's total output. Although China's peanut planting area accounts for only 1/3 of the total area of oilseed crops, its output accounts for more than half of the country's total oilseed crop output. Therefore, peanut production plays a pivotal role in China's cash crops and oilseed market.
China's level of peanut production mechanization is relatively low, whether compared with other major grain crops or with developed countries in the world. At present, in China's peanut production process, mechanization of tillage and land preparation, irrigation, shelling and plant protection has been basically perfected, sowing and film mulching machinery is continuously maturing, but the variety, performance and quality of machinery for harvesting, pod picking and other production links still cannot fully meet requirements. Operations still mainly rely on human and animal power. Peanut production requires much labor and is highly labor-intensive, and has become heavy labor for farmers. Due to the adjustment of agricultural structure and the role of market regulation, it is estimated that by 2005 China's peanut planting area will reach more than 4.7 million hectares, and by 2015 it will reach more than 5.4 million hectares. Therefore, the application prospects of peanut production mechanization technology are broad.
Peanut production has many links and is highly labor-intensive, with low manual operation efficiency; mechanized operations have high efficiency and low production costs, and possess enormous advantages.
II. Key Points of Technology Implementation
(1) Mechanical deep plowing and subsoiling. For mechanical deep plowing, deep plow and subsoiler should be selected. When the plowing depth exceeds 25cm, the plow body is required to achieve topsoil turning with subsoiling below, and have good soil-breaking performance. For subsoiling, it is best to select an all-direction subsoiler, especially pre-sowing subsoiling, which can prevent water evaporation and loss, and can also achieve the purpose of improving soil properties.
Pay attention to the following matters during tillage:
① Tillage time: Deep plowing is best carried out in late autumn and early winter, to promote soil maturation, accumulate rain and snow, and preserve moisture and water. It should be no later than before Qingming of the following year. Subsoiling can be carried out before sowing.
② Plowing depth requirement: Not less than 20cm. Generally, sandy waterlogged low-lying land is not suitable for deep plowing; plains and semi-mountain slope loam land with thicker soil layers and better soil quality are suitable for deep plowing, with deep plowing of 30-50cm; mountain ridge dry barren land is not suitable for deep plowing, and 25cm is appropriate. Deep-plowed plots should have topsoil turned with subsoiling below, to prevent acidic subsoil from being turned up to the surface. The soil turning depth is 15-20cm, and surface vegetation should be covered below the 10cm tillage layer, with a coverage rate above 95%. The plowing depth is required to be uniform and consistent, and the surface after plowing should be level, with no repeated plowing or missed plowing.
2. Mechanical Sowing
Mechanical sowing requires a double-seed rate above 75%, a qualified hill-seed rate above 95%, and an empty hill rate not greater than 1%. During mechanical sowing, attention should be paid to:
(1) Sowing time: The suitable sowing period for peanuts should be determined according to variety characteristics, natural conditions and cultivation systems. For medium-late maturing varieties, sowing can be done when the 5cm soil temperature stably reaches 15°C-18°C; for early maturing varieties, when it reaches 12°C-15°C. Film mulching cultivation can advance sowing by about 10 days. All localities should determine sowing time based on the variation pattern of soil temperature and the temperature suitable for peanut germination.
(2) Sowing density: Generally, medium-maturing large peanuts should be 8,000-9,000 hills per mu (2 seeds per hill, the same below). The density for medium-maturing medium-sized peanuts is suitably 10,000 hills. However, it should be grasped that land with good soil fertility should have a correspondingly smaller density, and land with poor fertility should have a larger density.
(3) Sowing depth is generally about 5cm. For plots with lower soil temperature or high soil moisture, shallow sowing may be appropriate, but the shallowest must not be less than 3cm; conversely, it may be appropriately deepened, but not more than 6cm. Grasp the principle of “do not sow deep when dry, do not sow shallow when wet”.
(4) Compacting: For soil with poor moisture or high sandiness, timely compacting should be carried out after sowing.
3. Mechanical Film Mulching
Pay attention to the following points during operation:
(1) Plot selection: For film-mulched peanut planting, loam land with a relatively thick soil layer and medium or above fertility should be selected.
(2) Film-mulched peanuts have higher requirements for land preparation than open-field cultivation. Deep plowing should be carried out before winter, early spring harrowing should be done when the soil is still frozen, and ridging should be done before Qingming; sufficient base fertilizer should be applied before sowing; if moisture is insufficient, furrows should be opened and watered, and after the water infiltrates, soil should be covered and leveled, and after spraying herbicide, film mulching should be carried out.
4. Mechanical Harvesting and Mechanical Re-harvesting
The harvest period of peanuts should be determined according to the growth and development of peanuts and climatic conditions. When the plants show an aging state, the top stops growing, the upper leaves turn yellow, the basal and middle leaves fall off, and most pods are mature, this indicates that peanuts have reached the harvest period. From the temperature perspective, when the temperature is below 12°C, pod growth stops, and harvesting should be carried out promptly. All localities should determine the harvest period according to local conditions. During harvesting, the shedding loss of peanut pods should be minimized. The pod drop rate of mechanical digging should be below 3%. Mechanical re-harvesting should be carried out immediately after harvesting, but at present the efficiency of mechanical re-harvesting is too poor, and it is basically not applied.
5. Mechanical Pod Picking
At present, peanut pod picking machines can pick both wet pods and dry pods, but picking wet pods easily causes breakage of fresh tender pods. Where conditions permit, pods should be sun-dried before picking, but not too dry, to prevent pod breakage. Pod picking requires a picking cleanliness rate above 98%, a breakage rate not exceeding 3%, and a cleanliness degree above 98%.
6. Mechanical Shelling
Peanut pods should not be too moist, to avoid reducing efficiency; if too dry, they are easily broken. When the moisture content of peanut pods is below 6%, water should be sprinkled and the pods should be left to temper. Mechanical shelling requires a shelling rate above 98%, a breakage rate not exceeding 5%, a cleanliness degree above 98%, and a blow-out loss rate not exceeding 0.2%.
III. General Requirements for Machine Operation
1. Peanut Sowing and Film Mulching Machine
(1) Before operation, check and adjust the lubrication, fastening, rotation and other states of all parts to normal.
(2) Adding seeds: According to the requirements of the seed metering device, add suitable seeds. Seeds that are too large or too small should be removed.
(3) Adding and replacing chemical liquid: Prepare the chemical liquid as required, pour it into the chemical liquid tank, open the air inlet switch to inflate the tank, and test spray after the air pressure reaches the specified value. Note that the safety valve should be adjusted to the safe pressure to ensure safety. When replacing the chemical liquid, first loosen the tank cover to release air, and after the air is fully released, open the cover to add chemical liquid.
(4) Adding fertilizer: Add granular fertilizer that has been cleared of debris and is not caked into the seed box.
(5) Installing plastic film: Install the film roll on the film rod, load it onto the film roll rack, adjust the tightness and lock it.
(6) Starting operation: Align the machine unit with the operation position, pull the plastic film down from the film roller, press the film head with soil, open the chemical liquid switch, and start operation.
(7) Adjustment of sowing depth, row spacing, plant spacing, spraying amount and fertilization amount: By adjusting the height and horizontal position of the furrow opener relative to the frame, a suitable sowing row spacing can be obtained; by replacing the key wheel to change the transmission ratio (some models replace different seed metering wheels), a suitable plant spacing can be obtained; by changing the valve opening, the required application amount of chemical can be achieved; by adjusting the working length of the fertilizer discharge wheel, the required fertilization amount can be achieved.
(8) Ridge shape adjustment: Change the soil penetration depth of the turning-up shovel to adjust the appropriate ridge height. Increasing the turning-up depth increases the ridge height, and vice versa decreases it.
(9) Adjustment of the film mulching part: Changing the height and angle of the film spreading wheels can adjust the lateral tension of the plastic film. Lowering the film spreading wheels and increasing the inward inclination angle of the front side of the film spreading wheels enhances the degree of tension, and vice versa loosens it; changing the locking degree of the film roll adjusts the longitudinal tension. Locking the bolt enhances the longitudinal tension, and vice versa weakens it.
(10) Adjustment of soil covering amount: Changing the depth and angle of the soil covering discs can adjust the soil covering amount. Increasing the depth and increasing the angle of the soil covering discs relative to the forward direction increases the soil covering amount, and vice versa decreases it.
(11) Precautions
Starting, raising and lowering should be slow, forward speed should be uniform, no turning or reversing is allowed during operation, and the working status of all parts should be checked at any time, with abnormal conditions handled promptly.
2. Peanut Harvester
(1) Install with the tractor's three-point hitch, and note that the universal joint square shaft yoke and the square shaft sleeve yoke should be in the same plane.
(2) Adjustment of soil entry angle: Change the length of the tractor's longitudinal pull rod to adjust the soil entry angle. Extending the pull rod makes the soil entry angle smaller, and vice versa larger.
(3) Adjustment of soil entry depth and conveying chain lifting angle: By changing the connection hole position between the ground wheel bracket and the longitudinal beam, adjust the height of the ground wheel relative to the frame, thereby changing the soil entry depth and the lifting angle of the conveying chain. Raising the ground wheel increases the soil entry depth and makes the lifting angle smaller; conversely, the soil entry depth becomes shallower and the lifting angle becomes larger.
(4) Adjustment of conveying chain tightness: Adjust the chain adjustment bolts to change the distance between sprockets, and tighten or loosen the conveying chain. When adjusting, loosen the guard block bolts and adjust simultaneously. If the chain is too long, the same number of links can be removed from both the left and right chains.
(5) Precautions: When soil moisture content is greater than 18% or the soil is too soft and the machine gets stuck, mechanical operation is not suitable. During machine operation, lifting should not be too high to prevent the universal joint from falling off, and lowering should not be too sudden to avoid damaging the shovel head. Frequently clean peanut vines and weeds tangled on the conveying chain and other parts.
3. Peanut Pod Picking Machine
(1) Installation: The matching power is a small four-wheel tractor or a 7.5KW motor.
(2) Drum clearance adjustment: Wet peanut vines require a larger clearance, and dry peanut vines require a smaller clearance, which can be adjusted according to the manual.
(3) Adjustment of the pod sliding plate and pod blocking plate: Change the up-down position of the pod sliding plate to reduce the blowing-out of peanut pods, and adjust the position of the pod blocking plate so that peanut pods do not jump out.
(4) Precautions: The impurity discharge outlet should face downwind, hands must not be extended toward the feeding inlet, feeding should be uniform and consistent, and stones, wire, rope ends, etc. must never be fed into the machine.
4. Peanut Shelling Machine
(1) Connect the motor to a 220V power supply, close the switch, let the machine unit run idle, and after it runs smoothly, uniformly feed peanut pods to begin shelling.
(2) Replace the cage grate: Replace with a suitable cage grate according to the size of the peanut pods.
(3) Adjust air volume: If there are too many kernels in the peanut shells, adjust the fan baffle to reduce the air volume; if there are too many impurities in the kernels, increase the air volume.
(4) Adjust the shelling drum clearance: If the breakage rate is too high, increase the clearance; if shelling is incomplete, reduce the clearance.
(5) Precautions: The impurity discharge outlet should face downwind, hands must not be extended toward the feeding inlet, feeding should be uniform and consistent, and stones, wire, rope ends, etc. must never be fed into the machine.
IV. Supporting Machinery and Types for Production Application
Peanut production machinery includes machinery for tillage and land preparation, sowing, film mulching, fertilization, field management, harvesting, pod picking, shelling, etc. Tillage and land preparation machinery and field management machinery (plant protection, irrigation) are general-purpose mechanical equipment. Here, the focus is on special machinery for peanut production.
1. Seeders include two major categories: human and animal powered seeders and tractor-drawn seeders. Human and animal powered seeders are relatively simple, generally single-row seeders. Their main working part, the seed metering device, is mostly of the combined grooved wheel type and the inner seed-filling vertical disc type, and there are also forms such as the scraper plate hole type and horizontal disc hole type. Common furrow openers are of the hoe-shovel type, boot type and other forms; in addition to the above forms, tractor-drawn seeder seed metering devices also include air-blowing type and air-suction type, generally two-row or four-row seeders.
2. Film mulching machines include two major categories: human and animal powered film mulching machines and tractor-drawn film mulching machines. Human and animal powered film mulching machines are relatively simple and are gradually being replaced by tractor-drawn film mulching machines.
3. Combined sowing and film mulching machines can complete ridging, bed preparation, herbicide spraying, film mulching, hole punching, sowing and other processes in one pass. Due to the obvious advantages of combined operation, combined sowing and film mulching machines are gradually replacing seeders and film mulching machines.
4. Peanut harvesters include segmented harvesting and combined harvesting. Machinery used for segmented harvesting includes peanut digging plows, peanut diggers and peanut re-harvesters; peanut combine harvesters can complete digging, soil shaking and pod picking in one pass. China's peanut combine harvesters are still in the research and development stage.
5. Peanut pod picking machines include simple hand-cranked pod picking machines, engine-matched pod picking machines, tractor-matched pod picking machines and motor-matched pod picking machines.
6. Peanut shelling machines include two main types: motor-matched and engine-matched, with small machines being more widely used.