Detailed Explanation of Key Techniques for Full Plastic Film Mulching Cultivation of Corn

1. Select improved varieties. Use high-quality hybrid varieties.
2. Select and prepare the land. Choose a plot with flat terrain, deep soil layer, medium or above fertility, and good drainage and irrigation conditions. Before sowing, pick out all stones, weeds, and residual roots, and carry out one deep plowing and one fine harrowing, meeting the standards of depth, looseness, fineness, levelness, and cleanliness.
3. Apply sufficient basal fertilizer. Basal fertilizer should be mainly organic fertilizer, combined with nitrogen, phosphorus, and potassium. Generally, 20-30 loads of human and livestock manure, 50 jin of urea, 60 kg of ammonium bicarbonate, and 50 jin of potassium fertilizer can be applied. In terms of fertilization method, ensure separation of seeds and fertilizer. First, open a fertilization ditch 5 cun wide and 4 cun deep in the center of the bed surface, apply the various fertilizers into the ditch in sequence, then cover with 2-3 cun of soil. To avoid poor root development in the early stage, failure to absorb fertilizer, and resulting fertilizer-induced old seedlings, it is necessary to irrigate the planting holes with dilute clear manure water at sowing time as seed fertilizer.
4. Raise seedlings at the right time. For land reserved in rows from the small spring crop, the seedling raising period can be chosen after "Jingzhe" (Awakening of Insects) and before "Chunfen" (Spring Equinox). For winter fallow land, the sowing period can be appropriately earlier.
5. Seedling raising method. To achieve warming and heat preservation as well as full, uniform, and strong seedlings, it is best to use plastic soft trays for seedling raising. The method is: prepare nutrient soil according to the conventional method for fertile-field seedling raising (not too thin), and use 40 plastic soft trays with 100 holes per mu. Before sowing, sort the seeds, sun-dry them, and conduct germination tests. At sowing, put nutrient soil into the tray holes, ensuring the nutrient soil occupies three-quarters or more of the hole volume, then press the seeds into the holes, 1-2 seeds per hole, cover with a layer of fine soil, and spray once with a sprayer until thoroughly watered. Other management is the same as conventional fertilizer-ball seedling raising.
6. Reasonable close planting. Whether on wheat land or winter fallow land, wide-narrow row planting should be adopted. For corn, use the method of double rows, staggered holes, hole punching, single plants, grading, and directional transplanting. Plant about 3,500 plants per mu, with a row spacing of 1.5 chi and a hole spacing of 5.5-6 cun.
7. Film covering requirements. When corn seedlings grow to the 2-4 leaf stage, begin transplanting. Before transplanting, first apply sufficient basal fertilizer, harrow and level the bed surface, then spray 100 g of diuron plus 50 g of methamidophos mixed with 50 kg of water per mu onto the bed surface to prevent weeds and cutworms, then pull the plastic film straight to cover the bed surface, then take soil to press the film edges, punch holes according to specifications with a slightly pointed wooden stick, then first irrigate the holes with clear manure water, then transplant the corn into the holes, and cover around the seedlings with fine soil.
8. Strengthen management. Prevent trampling by people and livestock. If broken film or exposed edges are found, promptly patch and press them down with soil. At the large trumpet stage, when applying ear fertilizer, the film can be removed and combined with weeding.
9. Fertilize according to seedling condition. During the corn growth period, if there are signs of fertilizer deficiency, at the seedling stage 2.5-5 kg of urea per mu can be applied with water beside the roots. At the large trumpet stage, 12.5 kg of urea per mu (or 35 kg of ammonium bicarbonate) can be applied deeply between two corn rows and four holes, covering while applying to improve fertilizer efficiency.
10. Other management. Do a good job of supporting stalks, detasseling, artificial supplementary pollination, and pest and disease control, and later remove residual film.