Corn is very sensitive to nitrogen fertilizer, on the basis of the combination of farmhouse fertilizer and phosphate fertilizer, in the range of 3-10 kg of urea per acre, 1 kg of urea can increase the yield of 6-11 kg of corn. Corn needs less phosphorus, but it cannot be missing, and the lack of phosphorus at the three-leaf stage will lead to the baldness of empty stalks in the future. Corn is also a zinc-loving crop, and the application of zinc fertilizer increases the yield by about 15%. The principle of corn fertilization is based on organic fertilizer, with heavy application of nitrogen fertilizer, suitable application of phosphorus fertilizer, increased application of potassium fertilizer, and combined application of micro fertilizer, such as EDTA Zn. Farmhouse fertilizer is mixed with phosphorus, potassium and micro fertilizer as base fertilizer, and nitrogen fertilizer is mainly topdressed. Spring corn topdressing should be light before and then heavy, and summer corn should be heavy before and then light.
Experiments have shown that 5 kg of nitrogen, 2 kg of phosphorus and 3 kg of potassium are required for every 100 kg of maize yield increase on medium fertility plots. This amount of fertilizer is very simple to use, just multiply the number of 100 kilograms of increased yield by the amount of fertilizer needed for 100 kilograms of grain. This is only a reference calculation method, and the specific application should be appropriately adjusted according to the place and different varieties. The reference fertilizer amount per mu of 1,000 kg of corn is: 1500 kg of farm fertilizer, 9-11 kg of nitrogen, 4-5 kg of phosphorus, 5-6 kg of potassium, and 1 kg of zinc fertilizer.
(1) open field spring corn: the required phosphorus, potassium, zinc fertilizer and 2-3 kg of urea and some fumate humic acid should be mixed with farmhouse fertilizer, applied to the seed hole, suitable for sowing. The remaining nitrogen fertilizer is reserved for top dressing. Mulching direct seeding corn in mountainous areas: Mulch corn grows strongly and consumes more nutrients. It is necessary to use phosphorus, potassium, zinc fertilizer and 70% nitrogen fertilizer required for the whole growth period of corn as the base fertilizer. The method is to cut a furrow 3-4 inches deep and about 8 inches wide between the two rows of corn sown. Nitrogen fertilizer is applied to the bottom layer first, and then all phosphorus, potassium, Fumate humic acid and zinc fertilizer are mixed with farmhouse fertilizer and applied on top of nitrogen fertilizer. Then the ridge is mulched, the ridge height is 2-3 inches, and the film is sown and mulched.
(2) Seed fertilizer for uncoated seeds, dry seeds for 2-3 days before sowing, add one or two taels of water with zinc fertilizer, mix 1.5-2 kg of seeds, pile up for 1 hour, spread out and dry in the shade to sow seeds. When sowing, qualified farmers use about 20 picks of human and animal manure and urine to mix 2 kg of urea per mu, and sow seeds while showering the nest to achieve full seedlings and strong seedlings.
1. Top dressing of spring corn in the open field should be light in the front and heavy in the back. Nitrogen fertilizer topdressing fertilizer (6-7 leaf stage) accounted for 1/3 of the total nitrogen application, and trumpet fertilizer (10-11 leaf stage) accounted for 1/3.
2. Summer corn topdressing should be heavy before and light after. Due to the busy farm work and tight agricultural time, most of the summer sown corn is planted under white seeds, and top dressing is very important. Jointing fertilizer (5-6 leaf stage) should account for two-thirds of the total nitrogen application rate, and trumpet fertilizer (10-11 leaf stage) should account for one-third.
3. Transplanting corn top dressing: When transplanting, about 10 kg of urea or other nitrogen fertilizers of the same nutrient amount are mixed into human manure and urine per mu. Put nutrient seedlings first, and then drench manure and then cover the nest to replace jointing fertilizer. At the bell stage, about 15 kg of urea is used again.
4. Mulch film corn: due to the sufficient amount of base fertilizer and long fertilizer efficiency, 30% of the unapplied nitrogen fertilizer per mu will be top-applied at the bell mouth stage. The method is to make a fertilizer hole every two corn plants and apply fertilizer.