High-yield and high-efficiency cultivation techniques and precautions for corn (Poaceae)
Corn is an annual herbaceous plant of the genus Zea in the grass family (Poaceae). Common names: maize, corn cob, bao gu, bao mi, bao su, yu jiao, bao mi, pearl millet, bao lu, da lu su; in Liaoning, Northeast China it is called pearl grain, in Chaozhou dialect it is called yi mi ren, in Cantonese it is called su mi, and in Minnan dialect it is called fan mai. The high-yield and high-efficiency cultivation techniques and precautions for corn are as follows:
1. Variety selection
1.1 Select hybrid corn varieties that have passed approval and are suitable for cultivation in Dali.
1.2 Varieties should combine high quality, adaptability, high yield and stress resistance, with good overall resistance.
2. Seed quality
Seed quality should comply with the provisions of GB4404.1. Germination rate ≥85%, purity ≥96%, cleanliness ≥99%, moisture ≤13%.
3. Land selection: choose plots with suitable soil pH, relatively high organic matter content, good water and fertilizer retention, and good drainage and irrigation conditions, with medium to high fertility.
4. Sowing
4.1 Timely sowing
According to the results of corn sowing-date trials conducted in the flat dam area of Dali City, the best sowing period in the dry-farming belt at the edge of the dam area is April 1 to May 10.
4.2 Sowing rate
The sowing rate is 2.5 kg to 3.0 kg per mu.
5. Standardized planting
Standardized plastic film mulching cultivation, sowing in double rows at the right soil moisture. Use plastic film 70-80 cm wide, sow in wide-narrow row pattern, with wide rows 60-70 cm, narrow rows 40 cm, and ridge height 15 cm.
6. Reasonable close planting
Reasonable close planting means suitable row and plant spacing, a reasonable starting population and distribution; determine a reasonable population structure according to soil type, altitude, and the characteristics of the selected variety. The yield per unit area of corn is composed of three factors: the number of ears per mu, the number of grains per ear, and the 1000-grain weight. According to many years of density trial results: for spreading-type varieties, 4500-5000 plants per mu is appropriate; for compact-type varieties, 5000-5500 plants per mu is best.
7. Scientific fertilization
According to soil nutrient abundance or deficiency, the fertilizer requirements of corn and the results of field fertilizer response trials, adhere to the principles of combining organic and inorganic fertilizers, combining major, medium and trace elements, combining land use with land maintenance, and balancing input and output, with controlled nitrogen, reduced phosphorus, supplemented deficient elements and increased potassium, in order to improve fertilizer use efficiency; increase yield and quality; reduce production costs; and reduce agricultural non-point source pollution and protect Erhai Lake. On the basis of increasing organic fertilizer application, apply corn-specific long-acting compound fertilizer as base fertilizer, with a fertilizer effect period of 120 days; do not apply jointing fertilizer, and apply ear fertilizer judiciously. The specific fertilization method is:
7.1 Base fertilizer: apply 1500-2000 kg of farmyard manure or 400-600 kg of bio-organic fertilizer per mu, 5-7 kg of urea, 40-60 kg of corn-specific long-acting compound fertilizer, and 1-2 kg of zinc fertilizer.
7.2 Ear fertilizer: at the 10.5-11 leaf stage (about 60 days after sowing), remove the plastic film and, in combination with intertillage and heavy earthing up, apply 15-20 kg of urea and 6-8 kg of potassium fertilizer per mu (or apply 10-15 kg of urea and 15-20 kg of potassium sulfate type compound fertilizer (15:15:15) per mu).
8. Strengthen management
8.1 Seedling stage management: the main goals of seedling stage management are full, uniform and strong seedlings, flat stem base, short sturdy plants, dark green leaf color, and well-developed root system, and these should be emphasized.
8.2 Check seedlings and fill gaps: after corn emerges, it is necessary to check the seedlings and fill gaps in time. Methods for filling gaps: first, reseed; second, transplant seedlings raised at the field edge and corners, with transplanting carried out after 4 p.m.; third, thin dense areas to fill sparse areas, transplanting with soil. After transplanting, enough settling water must be watered, and gap-filling transplanting must be done before the 3.5-leaf stage.
8.3 Thinning and final singling of seedlings: to prevent seedlings from crowding each other, competing for light and fertilizer, and wasting nutrients and water, thinning must be done at the 3-leaf stage; thinning should remove dense plants and keep sparse ones, remove weak plants and keep strong ones, remove small plants and keep large ones, and remove diseased plants and keep vigorous ones. When corn seedlings grow to the 5-leaf stage, the final stand should be determined in one operation according to the planted variety, soil fertility level, planned yield and planned number of plants.
8.4 Topdressing and intertillage: after final singling, decide whether to carry out seedling control according to the growth condition of the seedlings. Seedling control should follow the principle of “control late rather than early, control dark rather than yellow, control wet rather than dry”, then carry out intertillage and weeding. Apply extra fertilizer to weak seedlings, and apply seedling fertilizer in time when plants grow to the 6-6.5 leaf stage.
9. Integrated control of diseases, insects, weeds and rodents
In Dali City, the main threats to corn are: first, cutworms damaging seedlings; second, rodent damage; third, corn rust; fourth, northern and southern corn leaf blight; fifth, corn borers; and sixth, aphids.
9.1 Use green control methods, installing solar insect-killing lamps and high-pressure mercury lamps to trap and kill pests. After sowing and emergence, promptly use Baishude (beta-cypermethrin) to control cutworm damage. After sowing, uniformly place rodenticide to prevent rodent damage.
9.2 Disease control methods: control of this disease should focus mainly on planting resistant varieties, strengthening agricultural control, supplemented by necessary chemical control. (1) Select disease-resistant varieties. (2) Strengthen agricultural control, sow early at the appropriate time, and avoid the peak period of disease occurrence. (3) Apply composted manure, increase potassium fertilizer, avoid partial or excessive nitrogen fertilizer, and improve plant disease resistance. (4) Strengthen field management, do a good job of intertillage, weeding and earthing up, remove the bottom 2-3 leaves, reduce field relative humidity, make plants robust, and improve disease resistance. (5) Clean the field, remove diseased residues, and bury them deeply in a centralized manner to reduce sources of infection. (6) Implement crop rotation. (7) In Dali City, corn diseases generally occur as mixed infections, but rust is still the main one; at the early stage of disease onset, use a mixture of epoxiconazole (3 packets per mu), triadimefon (2 packets per mu), and organosilicon (3 packets per mu) for control.
10. Requirements for corn harvest, transportation, storage and by-product handling
10.1 Timely harvest
10.2 It is forbidden to thresh and dry grain on roads, asphalt pavements and places with serious dust pollution. It is strictly forbidden to transport mixed with toxic, harmful, corrosive or odorous items.
10.3 Store in a place protected from light, at room temperature, dry, free from insect and rodent damage, and with moisture-proof facilities. It is strictly forbidden to store mixed with toxic, harmful, corrosive, mildew-prone, moisture-prone or odorous items. If warehouse disinfection or fumigation treatment is carried out, the chemicals used should comply with relevant national food hygiene and safety regulations.
10.4 By-product handling
The by-products produced, such as straw and corn cobs, should be comprehensively developed and rationally utilized; returning straw to the field or planting dual-purpose grain-and-forage types is encouraged; burning, random piling, discarding and polluting the environment are strictly forbidden.