The basic principle of fertilization for summer corn is to apply nitrogen, phosphorus, potassium and trace fertilizer together and in a balanced way; Deep application of nitrogen fertilizer and topdressing by stages; Combine water and fertilizer to improve fertilizer efficiency. According to the research, it is necessary to produce 100 kg of corn seeds.
Absorb 2-4 kg of pure nitrogen, 0.7- 1.5 kg of phosphorus pentoxide and 3.2-5.5 kg of potassium oxide. According to the law of maize fertilizer demand, the reasonable fertilization method and suitable fertilizer ratio were determined.
In order to achieve high quality and high yield of corn.
The following specifically introduces the methods of applying fertilizer before sowing, timely topdressing and topdressing outside the roots of summer corn:
1. Apply base fertilizer before sowing summer corn. Mainly organic fertilizer and part of chemical fertilizer, straw can also be directly returned to the field by using the previous wheat, but a proper amount of nitrogen fertilizer (some nitrogen is needed when straw is decomposed) should be applied.
Centralized application is better. Generally, 40 kg of 25% compound fertilizer or 25 kg of ammonium bicarbonate plus calcium superphosphate 15-25 kg and potassium chloride 10- 15 kg are used. Trace element fertilizers such as zinc, molybdenum and boron can be used as base fertilizers.
Application, the dosage is zinc sulfate 1-2 kg/mu, molybdenum sulfate 1 kg/mu and borax 1 kg/mu. It can also be used for seed dressing, seed soaking or foliar spraying. Intercropping corn is difficult to apply base fertilizer in most plots, and generally a small amount is decomposed.
Use farmyard manure or nitrogen fertilizer as seed fertilizer, use urea or diammonium phosphate as seed fertilizer 3-4 kg/mu, and separate the fertilizers from the seeds to prevent seedling injury.
2. Summer corn should be topdressing at the right time. Topdressing of summer maize soil mainly depends on the grasp of fertilization time and amount. One is seedling fertilizer. Seedling fertilizer is the main fertilizer applied after corn planting. Generally, it depends on 6 ~ 8 plants.
Top dressing When the leaves are visible, after the third leaf of corn is unfolded, the nutrients in the endosperm of the seed have been exhausted, the roots begin to absorb nutrients from the soil, and the vegetative organs of corn grow vigorously. If the nutrient supply cannot keep up, it will seriously affect corn.
At this time, topdressing can meet the needs of growth and development and form strong seedlings. The amount of seedling fertilizer accounts for about 30% of the amount of nitrogen topdressing, which is usually topdressing after seedling establishment and before jointing. Lay a good foundation for big ears and more ears. sow seeds
For fertile fields, the amount of seedling fertilizer can be appropriately reduced and the topdressing time can be postponed. Generally, 3-5 kg of urea or 3-5 kg of ammonium bicarbonate 10- 15 kg can be applied topdressing per mu. The second is ear fat. Ear fertilizer refers to the corn before heading.
From 10 ~ 15 days, it can be seen that topdressing is carried out when the leaves are 14 ~ 16, which is the key period to determine the ear size and grain number. At the peak of female ear floret differentiation in maize, vegetative growth and reproductive growth go hand in hand, with stems and leaves
And the root system needs to absorb a lot of nutrients from the soil, and the nutrients of various organs are quickly transported to the female ear. Timely topdressing ear fertilizer can significantly improve corn yield. Spike fertilizer generally accounts for the total.
50%-60% of the amount of fertilization, generally 8- 10 kg of urea, 20-25 kg of ammonium bicarbonate, or 0/5 kg of ammonium nitrate/kloc-0 per mu. If the soil moisture is poor and there is no irrigation condition, it can be dissolved with 2% urea.
Liquid as root irrigation fertilizer, 80- 100 ml per plant.
3. Topdressing the summer corn outside the root. Topdressing outside the roots, mainly spraying foliar fertilizer, is generally applied at seedling stage, jointing stage and filling stage. Spraying 0. 1%-0.3% zinc sulfate aqueous solution at seedling stage can prevent corn from turning white.
In the occurrence of mosaic disease of seedlings, spraying 0.2%-0.3% potassium dihydrogen phosphate for 2-3 times at jointing stage can make strong stems lodging resistant and grow stably. Grain filling stage is the key period to determine the number of grains per ear and grain weight of maize, which needs a certain degree.
Nutrient supply, soil fertilization uses more fertilizer, and the effect is slow. If foliar spraying fertilizer is used, the effect will be quick and obvious. The type of fertilizer can be determined according to the appearance of corn. If nitrogen, phosphorus and potassium are insufficient, urea 1.5 kg and phosphoric acid ⅱ can be used.
Potassium hydrogen 100g, spraying 50-60kg of water; If nitrogen, phosphorus and potassium are insufficient and zinc is deficient, zinc sulfate 100g can be added to the above solution for spraying; For those who only need nitrogen, 2% urea solution can be sprayed on the leaves, generally.
2-3 times is enough, but when topdressing, we should pay attention to the appropriate concentration and order of magnitude time to play a better role.