How to scientifically topdress corn

Corn is a high-yield crop, which requires a large amount of fertilizer. It must be rationally fertilized to meet the nutrient needs of corn throughout its growth period. Therefore, during the growth and development of corn, scientific topdressing should be carried out according to the characteristics of each growth period to achieve the purpose of high quality and high yield.

First, master the timing of topdressing

During the whole growth process of corn, the peak of absorption is at jointing, booting and flowering. Therefore, the three attack and topdressing methods of attacking stalks, attacking and attacking are often used. The stalk fertilizer is in 6-8 leaves, and the seedling height is 30 cm. The attacking stalk fertilizer can promote the enlargement of the upper leaves of the corn, enlarge the photosynthesis area, prolong the functional period of the lower leaves, and lay a good foundation for promoting roots, strong stalks and increasing ears. The ear-shooting fertilizer is topdressed in the corn big horn period (10-15 days before the tasseling, 12-13 leaves). This is the most vigorous stage of corn growth and development. It requires a lot of water and is a key period for determining the size of the ear and the number of grains per ear. At this time, the application of panicle fertilizer, fertilizer and water attack can not only meet the fertilizer and water needs of panicle differentiation, but also increase the photosynthetic productivity of the middle and upper leaves, so that the input ear has more nutrients, and the grain is more and full, which has a significant effect on increasing yield. The attacking fertilizer refers to the beginning of extraction of the fringe of the ear, and a top dressing before and after pollination. Mainly to prevent post-fertilization, extend the functional period of the upper leaves, promote grouting, increase grain weight, and increase yield.

The number of top dressings should be determined according to soil fertility, fertilization amount, bottom and mouth fat. Some can do the attacking and attacking of the attacking attack once in the big squat period, or it can be topdressed twice in the jointing and big trumpet period. But the last time you want to chase less, after the next time to chase some, whether to chase the grain fertilizer depends on the soil fertility situation. In the later stage, the soil that is easy to be de-fertilized can be less chased by a bit of attacking fertilizer, so as to avoid excessive tantilization and cause late-ripening of the greedy and green.

Second, pay attention to topdressing methods

Corn belongs to deep root crops and fertilization methods vary from place to place. The roots of the crops are fattening, and the strongest part of the fertilizer is the root tip. The fertilizer should be applied to the wet soil layer that is most easily absorbed by the roots. Therefore, the town adopts a planing method of shaving or eye-catching to better exert the efficacy of the fertilizer. After deep application, it must be covered in time. In order to prevent the loss of nitrogen and the burning of seedlings, deep application is an important measure to prevent nitrogen loss and volatilization. At the same time, the fertilizer can be fully adsorbed by the soil, reduce the loss and increase the utilization rate of nitrogen fertilizer. According to the test, deep fertilization 10~12 cm can increase nitrogen utilization rate by about 30% and increase yield by 15%. Therefore, corn topdressing must be in a suitable position. In general, the application of 10 cm deep is the ideal depth, the suitable topdressing position of corn jointing fertilizer is 10 to 12 cm from the plant; the topping period is 15 to 20 cm from the plant.

3. It is not advisable to fill the water immediately after applying urea.

Urea is one of the best fertilizers for top dressing. However, it is most difficult to use urea as a top dressing. Urea is slightly hygroscopic and can be completely dissolved in water. It is a neutral fertilizer. After the application, no residue remains in the soil and is a non-component fertilizer. It has a prominent feature that the contained amide nitrogen cannot be directly absorbed by the crop and must be converted into ammonium nitrogen by the action of soil microorganisms before being utilized. If water is applied immediately after application, it will be dissolved by water. Because the adsorption between soil colloid and urea is very weak, urea has great fluidity in the soil, especially flooding with large water, which will cause urea to drip deep into the layer and reduce fertilizer efficiency. Therefore, it is not advisable to fill the water immediately after applying urea. It is even more unscientific to say that urea is applied before the rain. So how do you apply urea scientifically? First of all, we must understand the weather conditions, mainly the temperature. When urea is used at 10 ° C, the conversion time takes 7 to 10 days, and at 20 ° C, it takes 4 to 5 days, and at 30 ° C for 2 days, it is completely converted. Master this and determine the irrigation time after topdressing based on temperature conditions. Secondly, we must understand the soil conditions. The fertile soil transforms faster than the thin soil, and the clay soil is faster than the sandy soil. After applying urea to viscous and fertile soil, it can be pre-filled with thinner and sandy soil. The third should be applied in combination with organic fertilizers. Fourth, adopting methods of deep application and covering soil to accelerate the transformation and provide nutrients for crops.

Fourth, appropriate control of the amount of fertilizer

The amount of corn topdressing should be based on soil fertility and planting density. According to the Jilin Academy of Agricultural Sciences, the economic fertilization amount of high-fertility black land corn is 8-9 kg per mu, except for 2.5-3 kg of mouth fertilizer, and the remaining 5.5-6 kg (ammonium nitrate 19.1-21 kg/ Mu) should be used for all topdressing. The economic fertilization amount of medium and low fertility plots is 10-11 kg per mu. Except for 3.5-4 kg of mouth fat, the remaining 6.5-7 kg (22.75-24.5 kg of ammonium nitrate) should be applied as top dressing.