1. The characteristics of corn nutrient requirements in different growth periods
Each growing period of corn needs different nutrient ratios. From emergence to jointing, maize absorbed 2.5% of nitrogen, 1.12% of available phosphorus, and 3% of effective potassium; from jointing to flowering, it absorbed 51.15% of nitrogen, 63.81% of available phosphorus, and 97% of effective potassium; from flowering to maturity, it absorbed nitrogen 46.35 %, available phosphorus 35.07%, effective potassium 0%. The critical period of corn nutrition: The critical period of corn phosphorus nutrition is in the three-leaf stage, generally the seed nutrition shifts to the soil nutrition period; the critical period of maize nitrogen is later than the phosphorus, usually in the period from vegetative growth to reproductive growth. The critical period has little demand for nutrients, but the nutrients should be comprehensive and the proportion should be appropriate. Too little or unbalanced nutrients during this period will have significant adverse effects on the growth and development of corn, and no matter how to supplement the lack of nutrients will not help. The maximum nutrient efficiency of corn: the maximum efficiency of corn during the big bellmouth period. This is the period when corn nutrient absorption is fastest. During this period, the absolute quantity and relative quantity of nutrients required by maize were the largest, the absorption rate was the fastest, and the effect of fertilizer was the greatest. At this time, the fertilizer application amount was appropriate, and the effect of increasing maize yield was most obvious.
2. The demand for nutrients during the whole growth period of corn
The growth of corn needs to absorb a variety of mineral nutrients from the soil, of which nitrogen is the most, followed by potassium, and phosphorus is the third. In general, for every 100 kilograms of grains produced, 2.5 kilograms of pure nitrogen, 1.2 kilograms of phosphorus pentoxide, and 2.0 kilograms of potassium oxide are absorbed from the soil. The ratio of NPK: 1:0.48:0.8
Second, fertilization method
1, basal fertilizer: It can be combined with cultivation or shallow ploughing. It can use the post-effect of organic fertilizer and phosphate fertilizer of winter wheat, or use the method of wheat stubble returning straw to make up for the deficiency of corn basal fertilizer. Maize is a sensitive zinc crop. Zinc in corn can achieve significant yield increase. Under normal circumstances, 1 to 2 kg of zinc sulfate per acre is used as a base fertilizer, which can increase production by more than 10%.
2. Seed Fertilizer: There are various methods for applying seed fertilizer, such as seed dressing, soaking, sticking, and acupuncture. Seed dressing: Humic acid, bio-fertilizer and micro-fertilizer can be used. The fertilizer can be dissolved, sprayed on the corn seed, sprayed and mixed, so that the fertilizer solution is evenly immersed on the surface of the seed and sown after drying. Soaking: The fertilizer is dissolved to a certain concentration, the seeds are soaked in the solution for 12 hours, and sown immediately after drying. Article Shi, acupuncture: Fertilizer appropriate Shi Shi, acupuncture, the amount of 2 to 5 kg, but the fertilizer must be separated from the seeds, deeper and better fertilization, the depth of 10 to 15 cm is appropriate. Urea, ammonium bicarbonate, ammonium chloride, and potassium chloride should not be used as seed fertilizers.
3. Top dressing: It should be carried out according to the characteristics of its fertilizer requirements. The first time, 10 to 15 days after the jointing (7 to 8 leaves), one-third of the total fertilizer was applied to promote stem growth and spike differentiation. For the second time, 10 to 15 days (10 to 11 leaves, big bell mouth period) of corn were used to top up two-thirds of the total amount of fertilizer in the corn tassels. If the summer corn is topdressed only once, it should be done in the small bellmouth (around 8 to 9 leaves), but not too late. Fertilizer should be planed or deep-cast or planted. The distance between the fertilizer and the seedling should be 7 to 10 cm. After fertilization, it should be sealed strictly to improve fertilizer efficiency.
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