What are the technical key points of the peanut peg-controlling cultivation method?

The peanut peg-controlling (AnM) cultivation method is a new peanut cultivation technique researched and invented by Shen Yujun, a famous Chinese peanut expert and professor at Laiyang Agricultural College. This technique controls the exposure time of the peanut hypocotyl and the atmospheric humidity at the base of the plant, promoting the production of the endogenous hormone ethylene, thereby controlling hypocotyl elongation and the time of pegging into the soil, reducing overripe pods and empty shriveled pods, and achieving the goal of many well-filled pods, high quality, and high yield. After large-scale demonstration and extension in Shandong, Hebei, Liaoning, Sichuan and other provinces, peanuts planted with the peg-controlling cultivation method emerged uniformly, grew vigorously, developed the first pair of lateral branches quickly, pegged in a concentrated manner, set pods uniformly, and ripened evenly, generally increasing yield by about 20%, with the highest reaching more than 35%. It also saves labor and effort and is suitable for mechanized operations, making it a major breakthrough in peanut cultivation technology.
The technical key points of the peanut peg-controlling cultivation method consist of three stages: A, n, and M:
The A stage mainly involves raising the cotyledon node by hilling soil so that it is exposed above the ground (or above the plastic mulch), in order to control pegging of early flowers. For peanuts grown in open fields, after sowing, the flat-topped ridge is changed to a pointed top (its cross-section closely resembles the capital letter "A"); when sowing on flat ground, after sowing the seeded rows are hilled into thick ridges with pointed tops. The top of the ridge is about 8 cm from the seed. When the hypocotyl is about 3-4 cm long (generally about 10 days after sowing), the loose soil on top of the ridge is removed, leaving only a thin soil layer 1 cm thick above the cotyledons. When removing the soil, the back of an iron rake or an upright palm can be used, and after gaining proficiency, other tools may also be used. The specific time for removing soil is best at 3-4 p.m. At this time, because the sprouting seedlings have not yet been exposed to light in the soil, the hypocotyl continues to elongate, and generally by the next morning the cotyledon node can rise above the ground (soil removal before emergence actually replaces the post-emergence seedling clearing of conventional cultivation). For flat-sown fine sandy soil, when the peanut seedlings emerge and push through the soil, creating small cracks, a hoe is pushed along the seeded rows to close the cracks and prevent the seedlings from being exposed to light too early, which can also play a role in raising the cotyledon node position; for the few seedlings that have already been exposed to light for a short time, after the cracks are closed they are once again in a dark environment, and the hypocotyl can still resume elongation within a certain range and continue to raise the cotyledon node position. For peanuts grown under plastic film mulching, conventional cultivation's ridge-building, bed-making, and film covering is changed to flat-ground film covering to form beds. After sowing, on the sowing holes on the surface of the plastic film, conical mounds of soil 5 cm high are covered to delay the time of seedling exposure to light, prompting the embryonic stem to continue elongating. After the cotyledon node rises above the film surface on its own, the small soil mounds are then removed back into the furrows; if rain occurs before the cotyledon node rises above the film surface and causes the soil mounds to clump, measures should be taken promptly to eliminate cracks in the mounds and prevent the seedlings from being exposed to light too early. After peanut emergence, as long as the field is basically free of weeds and the surface soil is not compacted, intertillage is generally not carried out; when intertillage is needed, the method of stepping backward and deep hoeing the furrows can be used, with the hoe only pulled forward and not pushed, and the ridges must not be broken, so as to facilitate deep penetration of lateral roots. For plots with incomplete emergence, seedlings can be transplanted nearby to fill gaps. When transplanting, open deep holes and make the cotyledon node of the transplanted seedling higher than the ground, then fill with fine soil to half the length of the hypocotyl, water twice, and after the water infiltrates, fill soil to close the hole. Generally, about 5 days are needed for the seedlings to recover, which is better than reseeding.
The n stage mainly controls pegging. At the early flowering stage of peanuts, through intertillage, the soil on both sides of the ridge is hoed toward the inter-row space, so that the ridge forms an "n"-shaped narrow bank; even if the soil between the rows is higher than the ridge row, the peanut row should still be made into a narrow bank shape. This is conducive to ventilation and moisture dispersion, reducing the atmospheric humidity in the space at the base of the plant, and at the same time increasing the distance between the pegs and the soil surface, thereby slowing the elongation speed of the pegs and achieving the purpose of controlling pegging and pod setting of early flowers. The narrow bank formed in the n stage generally has a height of about 5 cm and a top width of about 6-7 cm. When implementing the n stage for flat-cultivated peanuts, the plants and rows can be hoed into a "W" shape so that the plants are located at the middle peak of the "W" shape, and the inter-row spaces become high and narrow soil ridges. For peanuts under film mulching, through the raising effect of the A stage, after the cotyledon node rises above the film surface, in an environment with high film surface temperature, relatively high wind speed, and relatively low atmospheric humidity, the downward penetration of early flower pegs is already controlled, so the n stage is generally no longer implemented in production.
The M stage mainly removes the control over pegging by building up ridges. Northern spring peanuts generally implement the M stage at the end of June or the beginning of July (that is, about 80 days before harvest). The implementation method is to use a large hoe with a grass ring and a slightly smaller hoe plate to first break the compacted surface layer, then deep hoe and pull vigorously between the ridge rows, building ridges with soil, so that the peanut rows naturally form concave (M)-shaped ridges that are both plump and steep with a top width of no less than 20 cm; for plots with low soil fertility, before building ridges, 2.5 kg of urea and 10 kg of high-quality superphosphate can be broadcast per mu under the plants of the n-shaped narrow banks to promote plant growth and development. When the peanut rows close in, hoe the furrows again to increase the height and thickness of the ridges, so as to facilitate drought resistance, drainage, and promotion of pod development. In addition, according to research, after peanut pegs enter the soil, if the soil moisture in the pod-setting layer is lower than 60% of the field maximum water-holding capacity, the ovary at the tip of the pegs that have entered the soil cannot develop into pods. Therefore, in production, in order to create good soil moisture conditions, the time for removing the control is often appropriately delayed. In Shandong Province, it is generally carried out around July 5, timely after rainfall or irrigation. The method for implementing the M stage for film-mulched peanuts is, at the peak pegging stage (generally mid-July for northern spring peanuts), to spread a 1 cm thick layer of fine soil on the film surface around the base of the plant with a diameter of about 20 cm, to help the pegs enter the film and increase the number of pods set.