Comprehensive Overview of Peanut Cultivation Techniques: Key Planting Points Explained in One Article

1. Crop Rotation and Soil Conditions
Peanuts are not tolerant of continuous cropping. When peanuts are replanted on the same land, the plants appear stunted with yellow leaves that drop early, there are more pests and diseases, and the pods are few and small. Proper crop rotation, especially paddy-upland rotation, has a good effect on preventing peanut wilt diseases (including bacterial wilt and crown rot). Peanuts flower above ground and form pods underground, so a good peanut field should have basic conditions such as a deep plough layer, a loose pod-setting layer, and relatively high fertility. According to measurements: the plough layer thickness is generally 30cm, and the upper pod-setting layer is generally a soft, loose soil layer 10cm thick, which facilitates peg penetration into the soil for pod setting. In high-yield fields, the average organic matter content of the plough layer soil is 0.656%, the average nitrogen content is 0.05%, the average phosphorus content is 0.127%, the average available potassium is 107×10-6, and the average exchangeable calcium is 0.226%.
2. Variety Selection and Seed Preparation
(1) Selecting good varieties. In recent years, many new peanut varieties have been developed across the country. Large peanut varieties include: Luhua 8, 9, and 10, Xuhua No. 5, Ganhua No. 5, Jihua No. 2, and Yuhua No. 10. These varieties are characterized by being shorter and smaller than the original varieties, with fewer branches, making them more suitable for close planting; they have large pods, thin shells, and regular pod shape, with stronger marketability. The full growth period is generally 130-140 days, 5-15 days shorter than the original medium-maturity varieties. The newly developed Luhua 14 and 15 have a growth period of only 125 days.
(2) Seed preparation
1. Autumn-planted seed saving (autumn planting for seed)
In the southern provinces and regions with two crops per year (spring and autumn), spring peanuts use seeds from the previous year's autumn-planted peanuts, which is called autumn-planted seed saving. Experimental research and farmers' experience both prove that seeds saved from autumn planting have a short storage time, are not prone to rancidity or mildew, have strong vitality, and can still maintain a relatively high emergence rate under adverse environmental conditions such as low temperature and continuous rain after sowing. The emergence rate is generally above 90%, about 30% higher than seeds from spring peanut seedlings, sometimes even more than 50% higher, and the yield can generally increase by about 20%.
2. Sun-drying seeds before sowing, timely shelling. Before sowing, sun-dry the seeds with shells for 1-2d, preferably on an earthen drying yard to avoid high-temperature damage to the seeds. Before shelling, a germination test should be conducted to determine the seed germination vigor and germination rate. Shelling should be done 1-2d before sowing, shelling and sowing as you go, to avoid premature shelling causing seeds to absorb moisture, become infected with pathogens, or suffer mechanical damage. After shelling, remove hybrid seeds, shriveled seeds, small seeds, broken seeds, seeds infected with pests and diseases, and seeds showing mildew characteristics; in particular, remove seeds with partially detached seed coats or slightly damaged cotyledons. Divide the remaining plump seeds into two grades by size: plump large seeds as grade one, and the rest as grade two. According to experiments: grade one seeds (90g per 100 seeds) used for planting produced an average pod yield of 286.4kg per 0.067 sq m, an 8.9% increase over the 263kg of grade two seeds (70g per 100 seeds).
3. Chemical seed dressing. When sowing, dressing seeds with fungicides such as 0.3% carbendazim and 0.5% fenaminosulf can prevent or reduce diseases; dressing seeds with 2%-3% chlordane emulsifiable concentrate and similar chemicals has a good effect on controlling underground pests and damage by birds and animals. Dressing seeds with rhizobium inoculant and molybdenum fertilizer can accelerate nodule formation and enhance the nitrogen-fixing effect of peanuts.
4. Pre-germination. Pre-germinating peanut seeds is an effective measure to ensure full stands. There are many methods of pre-germination. The methods currently promoted in various places include earthen kang pre-germination, sand bed pre-germination, and indoor pre-germination. These can be flexibly applied according to the conditions required for peanut seed germination. Machine sowing does not require pre-germination.
Points to note when soaking seeds for pre-germination: First, seeds must be graded and soaked separately so that seeds absorb water evenly and germinate uniformly. Second, when the seeds are first placed in warm water and the seed coats become wrinkled, do not stir them, to avoid the seed coats falling off. Third, pre-germination should not go on too long; it is best when the seeds just “show white”. Fourth, if rain prevents sowing after pre-germination, spread the seeds in a cool place to inhibit sprout growth.
　　
3. Land Preparation and Bed Formation
Peanuts are a deep-rooted crop, and appropriately deepening the plough layer helps increase yield and quality. It is best to harrow early on the basis of winter and autumn ploughing, to store water and conserve moisture and raise soil temperature. The ploughing depth is generally 26-33cm for winter ploughing and 14-17cm for spring ploughing. In addition, attention should be paid to leveling, loosening, fining, and moistening. Using narrow beds and high beds is one of the main measures to ensure high and stable peanut yields. For paddy field peanuts, the bed width is generally 132-165cm (including the bed ditch); for fields with low terrain and a high groundwater table, it can be reduced to 118.8-132cm. The bed height is 16.5-26.4cm. The bed ditch is preferably 33-39.6cm. Narrow beds and high beds facilitate drainage and improve the germination rate. For dry sloping land, the specifications of bed width 198-264cm and bed height 13.2-16.5cm are suitable. Ridge planting also facilitates irrigation and drainage, field management, raising soil temperature, and ventilation and light penetration.
For plastic film mulching cultivation, make beds according to the width of the film. If the film width is 80cm, the bed width should also be 80cm, of which the bed ditch is 30-33cm and the bed surface width is 47-50cm. After forming the beds, apply the film while there is moisture, making sure the film fits closely against the bed surface, and press the edges of the film firmly with soil.
　　
4. Timely Sowing
The suitable sowing date should be determined according to variety characteristics and local climate change patterns. Generally, pearl bean-type small peanuts can be sown as long as the soil temperature in the sowing layer is stably above 12°C. Common-type late-maturing large peanuts can only be sown when the soil temperature in the sowing layer is stably above 15°C. Film mulching cultivation can increase soil temperature, adding 195.3-370.8°C to the total active accumulated temperature over the full growth period compared with open-field peanuts. Therefore, the sowing date should be about 10 days earlier than local open-field sowing. Generally, the times when sowing can begin are: March in most parts of the south, February in Guangdong, and January in Hainan. Sowing early within the suitable sowing period is of great significance for fully utilizing effective accumulated temperature conditions to increase the pod-setting rate. Spring peanuts should be sown when local temperatures reach the above standards. For autumn peanuts, the main consideration is the adverse effect of low temperature and drought in the later stage on pod maturity, so autumn peanuts should mature as much as possible under temperature conditions above 18°C to facilitate full and plump pods. In central China, spring peanuts are sown between Qingming and Guyu, and peanuts intercropped with wheat are sown between Guyu and Lixia. The quality of peanut sowing should meet the requirements of full stand, uniform stand, and strong seedlings. Full stand means an emergence rate above 90%-95%; uniform stand means all germinable seeds emerge within 3-4 days of the first emergence; strong seedlings means that at emergence the cotyledons are exposed or half-exposed above the soil, the first expanded leaf has a long petiole, and the leaf blade is large and bright green. To ensure a full stand and increase unit yield, 3-4 days after peanut emergence, it is advisable to check and replant seedlings in time; replanted seeds should first be soaked and pre-germinated so as to catch up as much as possible with the growth rate of the earlier-sown large seedlings.
　　
5. Planting Density and Methods
1. Planting density. The density range for rational close planting of peanuts should be such that the rows close during the pod-setting stage. The general requirement for the growth appearance of rationally close-planted peanuts is “in fertile land the vines do not lodge, in poor land the rows can close.” Under general production conditions, the planting density of pearl bean-type peanuts is 27×104-33×104/hectare; for common-type peanuts it is 16.5×104-21×104/hectare. Under conditions of a long growth period, tall plants, strong branching, spreading-type varieties, as well as high temperature and rain, fertile soil, and high management levels, planting should be appropriately sparse. Otherwise, it should be denser.
2. Planting methods
Flat planting: This can be used in fields with deep soil layers that are not prone to waterlogging, but the yield is not as high as ridge planting. Flat planting is simple and labor-saving, the row spacing can be adjusted freely, the soil's productive capacity can be fully utilized, and moisture conservation is good; it is currently widely used. The disadvantage is that under poor drainage conditions it is prone to waterlogging, with more rotten pods.
Ridge planting: This facilitates irrigation and drainage; the soil on the bed surface is loose, aeration is good, the ground receives more light, and warming in spring is fast. Under the condition of good moisture conservation in spring, seedlings are strong and seed rot is light. Ridge planting peanuts allows thorough clearing of the plants and saves labor; during intertillage, seedlings are not easily buried and vines are not easily pressed. After earthing up to restore the ridge shape, it facilitates ventilation and light penetration, the diurnal soil temperature difference is large, and pod development is good. The disadvantage is that ridge formation requires slightly larger row spacing; generally when row spacing is less than 46.2cm, it is difficult to form ridges; when greater than 46.2cm, it is difficult to maintain density. Therefore, ridge planting is more suitable on land with relatively high fertility, lower density, or poor drainage prone to waterlogging.
High bed planting: This is suitable for low-lying, easily waterlogged land and hilly land that does not drain easily. Generally the bed width is 1.2-2m, the ditch width is about 30cm, and the ditch depth is 17-20cm. Then level the bed; it can be planted flat or planted on ridges.
The principle for determining peanut row and hill spacing is to both fully utilize soil productivity and light energy, and facilitate ventilation and light penetration between rows and plants. To facilitate intertillage, the row spacing should generally not be less than 25-35cm; in highly fertile fields, the contradiction between ventilation and light penetration in the middle and late stages is greater, so while reducing density, the row spacing should be appropriately widened (or wide-narrow row spacing used), but hill spacing should generally not be less than 16.5cm. At present, peanut row spacing is generally 33-53cm. In high-yield fields of 350-400kg, the row spacing is mostly 46-52.8cm, with a few at 59.4cm.
Peanut sowing methods include double-seed drilling, single-seed drilling, small clump hill sowing, wide-narrow row, and wide row narrow plant spacing. Generally 2-3 seeds are sown per hill, and the sowing depth is preferably 16-17CM; for film mulching cultivation the sowing depth is 3cm. In the method of sowing first and then mulching, after the seedlings emerge and the film holes are opened, a handful of soil should be placed around the holes; in the method of mulching first, soil should be placed over the film holes when pressing firm after sowing.
　　
6. Peanut Nutrition and Fertilization
Peanuts have a relatively strong tolerance to poor soil, and applying a small amount of fertilizer can obtain considerable yield. However, to rapidly increase peanut unit yield, scientific fertilization is one of the basic measures.
(1) Peanut requirements for nutrient elements and absorption dynamics. According to research results from the Guangdong Academy of Agricultural Sciences, at a yield level of 266.5-290kg of peanuts per mu, 16.01-19.46kg of nitrogen, 3.38-3.89kg of phosphorus, and 7.8-10.24kg of potassium need to be absorbed. For every 50kg of peanut pods produced, about 3-3.4kg of nitrogen, 0.65-0.7kg of phosphorus, and 1.45-1.75kg of potassium need to be absorbed. The absorption of major nutrient elements by peanuts is nitrogen > potassium > phosphorus > calcium.
The dynamics of nutrient absorption by peanuts at different growth stages are: absorption is relatively low at the seedling stage, gradually increases at the flowering and pegging stage, is highest at the pod-setting stage, and declines again at the maturity stage. According to research results from the Peanut Research Institute of the Chinese Academy of Agricultural Sciences: at the peanut seedling stage, nitrogen absorption (as a percentage of total absorption during the full growth period, the same below) is 4.8%, phosphorus 5.19%, and potassium 6.73%; at the flowering and pegging stage, nitrogen absorption is 17%, phosphorus 22.64%, and potassium 22.25%; at the pod-setting stage, nitrogen absorption is 48.5%, phosphorus 49.53%, and potassium 66.35%; at the maturity stage, nitrogen absorption is 29.7%, phosphorus 22.64%, and potassium 4.67%.
(2) Fertilization methods. Peanut fertilization should follow the basic principles of mainly organic fertilizer with chemical fertilizer as a supplement; mainly basal fertilizer with topdressing as a supplement; topdressing mainly with seedling fertilizer, supplemented by flower fertilizer and pod-strengthening fertilizer; and combined application of nitrogen, phosphorus, potassium, and calcium.
1. Basal fertilizer. The application rate of peanut basal fertilizer should generally account for 70%-80% of the total fertilization amount, mainly decomposed organic fertilizer, combined with inorganic fertilizers such as superphosphate, potassium chloride, and lime. The nitrogen, phosphorus, and potassium in the basal fertilizer can be applied at a ratio of 1:1:2. When the amount of basal fertilizer is small, it is better to concentrate it as seed-covering fertilizer to benefit seedling growth. Plant ash, potassium sulfate, lime, and similar materials should be uniformly broadcast in combination with pre-sowing land preparation, raked evenly, and then beds formed for sowing. Superphosphate should be composted with decomposed farmyard manure more than 15-20 days in advance to help improve the fertilizer efficiency of phosphorus.
2. Topdressing should be mainly at the seedling stage, supplemented by topdressing at the flowering stage and pod-setting stage; at the full-pod stage, foliar topdressing should be decided according to plant condition.
(1) Seedling stage: Applying quick-acting nitrogen fertilizer at the 3-5 leaf stage has a good effect on promoting early and vigorous branching and increasing the number of flowers and pods. Generally, 5-6kg of urea per mu, or 1500-2000kg of human and livestock manure water.
(2) Flowering and pod-setting stage: After initial flowering, nutrient absorption increases sharply, but rhizobia also begin to continuously supply nitrogen nutrition to peanuts. If nitrogen fertilizer is applied excessively as topdressing, spring peanuts are prone to excessive vegetative growth of stems and leaves in the later stage and lodging. Therefore, after flowering, nitrogen fertilizer is generally not applied as topdressing to the root zone; instead, the main focus is on applying calcium fertilizer and potassium fertilizer at the initial flowering stage in combination with the last intertillage and weeding. Usually 25-50kg each of lime and plant ash are applied per mu.
　　
7. Water and Management
(1) Peanut water requirement patterns. Peanuts have a relatively strong drought tolerance and, like sorghum and foxtail millet, are called “the camel of the crop world.” According to measurements, peanuts consume 450-500 grams of water for every 1 gram of dry matter synthesized. The general trend of water requirement at different growth stages is low at both ends and high in the middle, that is, less water is needed at the seedling and full-pod stages, and more water is needed during the flowering and pod-setting period. The water requirement of each growth stage as a proportion of the full growth period is: 3.2-7.2% from sowing to emergence, 11.9-24% from full emergence to flowering, 48.2-59.1% from flowering to pod setting for medium-maturity large peanuts; 52.1-51.4% for early-maturity peanuts. At the full-pod maturity stage, 22.4%-32.7% for medium-maturity large peanuts; 14.4-25.1% for early-maturity varieties. The critical period for peanut water requirement is
the full flowering stage, and the period of greatest water requirement is the pod-setting stage. That is, the full flowering stage is the most water-sensitive period in the life of the peanut; once water is lacking, the loss to peanut yield is greatest. The pod-setting stage is the period of greatest water requirement in the life of the peanut, and yield loss caused by water shortage and drought is very large. Therefore, these two growth stages must ensure water supply and cannot lack water.
(2) Peanut water management. Peanut water management should both ensure sufficient water supply, especially at the flowering and pegging stage and the pod-setting stage, and prevent the harm to peanuts from drought and excess water. Generally, maintaining 50-70% of the soil's maximum water-holding capacity is suitable. When the water-holding capacity falls below 40%, irrigation should be noted; the irrigation method should be furrow irrigation along the ridges, not flooding irrigation, and after irrigation a deep intertillage should be carried out in the ridge furrows at an appropriate time to conserve moisture and prevent drought. When the water-holding capacity is greater than 80%, drainage should be noted. The water management requirements differ at different growth stages. They can be summarized as “dry seedlings, moist flowers, moist pods.” That is, at the seedling stage it should be less, with the soil appropriately dry, to promote deep rooting and short, sturdy seedlings; at the flowering and pegging stage it should be more water, with the soil relatively moist, to promote flowering and pegging; at the pod-setting stage the soil should be moist, both meeting the needs of pod development and preventing excessive water from causing excessive stem and leaf growth and rotten pods and rotten pegs. Accordingly, it is more suitable to control soil moisture at about 50% of field maximum water-holding capacity at the seedling stage, about 70% at the flowering and pegging stage, about 60% at the pod-setting stage, and about 50% at the full-pod stage.
　　
8. Field Management
(1) Clearing around seedlings and seedling hardening
1. Seedling hardening. Seedling hardening, also called seedling tempering, refers to the technique of controlling water at the seedling stage to inhibit above-ground growth and promote downward root growth, thereby helping form short, sturdy seedlings. When water supply is restored, the second pair of lateral branches can more easily catch up with the growth of the first pair of lateral branches, making the plants more uniform and consistent, and giving play to the yield-increasing role of these two pairs of lateral branches; it also helps prevent lodging in the later stage. Seedling hardening is generally carried out when the seedlings have 4 true leaves, to the extent that drought does not affect normal physiological activity; weak, thin seedlings are not suitable for it.
2. Clearing around seedlings. Clearing around seedlings is a technical measure adopted to solve the problem of deep sowing for a full stand and the first pair of lateral branches being buried in the soil and affecting pod setting. Compared with not clearing, clearing around seedlings can increase yield by more than 10%. Clearing around seedlings should be carried out when the stand is basically complete. Combined with the first intertillage and weeding, use a small hoe to scrape away the soil around the peanut seedlings, allowing the two cotyledons and lateral buds to be exposed to light, inhibiting internode elongation, making the first pair of lateral branches develop robustly, and reducing the distance for pegs from the basal nodes and their secondary branches to enter the soil. After 15-20d, fill the excavated soil back into the holes and earth up to welcome pegging.
3. Raising the cotyledon node out of the soil. This is a new technique used in recent years. During peanut emergence, the seedlings crack the surface soil, and light enters through the cracks. After the sprouts see light, the hypocotyl stops growing, which is the fundamental reason why the cotyledon node does not emerge from the soil. The traditional cultivation method is to clear around seedlings and harden seedlings after the peanut stand is complete. Raising the cotyledon node out of the soil changes the traditional flat planting and ridge cultivation. That is, for open-field cultivation, according to the width of the sowing rows, form ridges, then sow peanuts on the ridges, then cover with soil to form ridges with pointed tops. 7-8 days after sowing, leave a thin layer of soil 1cm above the cotyledons, scrape the loose soil above onto the rows to pile up soil ridges 7-8cm high, and when the peanuts emerge, remove the soil ridges on the film. According to experiments, raising the cotyledon node out of the soil can increase the number of pods per peanut plant by 4-5, or even more. Realizing the mechanized peanut planting techniques of reducing seeds and increasing hills, close planting with single plants, and direct seeding with film mulching and raising the cotyledon node out of the soil can achieve mechanized peanut planting.