Does corn need to be fertilized frequently? What is the optimal frequency of fertilization?

In addition to seed selection, seed dressing, weeding, etc., when growing corn, fertilization is also a matter of great concern to farmers. How many times does corn need to be fertilized from sowing to harvesting? What kind of fertilizer do you use every time? What is the dosage? Today, the editor has compiled detailed knowledge about corn base fertilizer and top dressing for everyone. I hope it can be helpful to everyone. First, let’s look at an issue that most people are concerned about:

The best time for corn top dressing

Fertilization management of corn at the appropriate time can promote the fastest and largest growth of corn. Efficient absorption of nutrients can promote the growth of corn and increase yield. The best period for corn top dressing is during the trumpet period. During this period, the absolute and relative amounts of nutrients required by corn are the largest, the absorption speed is also the fastest, and the role of fertilizer is greatest. At this time, the amount of fertilizer applied is appropriate and the corn yield increases. The effect is most obvious.

However, there are different opinions on the issue of corn top dressing:

In the process of planting corn, we may hear many people saying that if we want to increase corn production, we must apply more fertilizer. The original meaning of the words is correct, but one premise is missing, that is, correct fertilization can increase corn production. Correct fertilization of corn is an important issue to achieve high, stable and efficient corn yield, but how to achieve the correct standard is a more complicated issue.

The sources of nutrients required by corn during its growth are divided into two types, one is the nutrients stored in the soil, and the other is the nutrients from the fertilizer applied, but the ratio of nutrients absorbed from these two sources is It is also affected by many factors and is relatively complex. It is difficult for ordinary growers to accurately calculate the required amount of fertilizer. Therefore, the editor below will tell you a method to roughly calculate the required amount of fertilizer. Generally speaking, it is relatively detailed and accurate. You can use it as a reference:

Where conditions permit Soil testing and fertilization can be carried out, and various nutrient contents in the soil should be tested every 3 to 5 years. Based on the fertilizer requirements of corn, planned yield, soil fertilizer supply capacity, fertilizer utilization rate of the season and other factors, the following formula can be used to roughly Calculate the amount of fertilizer to apply.

Corn requires different proportions of nutrients in each growth period. The characteristics of nutrient requirements of corn in different growth periods are:

From emergence to jointing, corn absorbs 2.5 nitrogen, 1.12 available phosphorus, and 1.12 available potassium. 3;

From jointing to flowering, it absorbs 51.15 nitrogen, 63.81 available phosphorus, and 97 available potassium;

From flowering to maturity, it absorbs 46.35 nitrogen, 35.07 available phosphorus, and 0 available potassium. .

The nutritional critical period of nitrogen, phosphorus and potassium

The critical period of corn phosphorus nutrition is at the three-leaf stage, which is generally the period when seed nutrition turns to soil nutrition;

Corn nitrogen The critical period of phosphorus is later than that of phosphorus, usually during the period when vegetative growth turns to reproductive growth.

The critical period does not require much nutrients, but the nutrients must be comprehensive and in appropriate proportions. During this period, too much, too little, or an imbalance of nutrients will have a significant negative impact on the growth and development of corn, and no matter how you supplement the deficient nutrients in the future, it will not help.

Nutrient requirements of corn during the entire growth period

Corn growth needs to absorb a variety of mineral nutrients from the soil, of which nitrogen is the most abundant, potassium is the second, and phosphorus ranks third. Three.

Generally, for every 100 kilograms of grain produced, 2.5 kilograms of pure nitrogen, 1.2 kilograms of phosphorus pentoxide, and 2.0 kilograms of potassium oxide need to be absorbed from the soil. The ratio of nitrogen, phosphorus and potassium is: 1:0.48:0.8.

Fertilizer application amount = (planned output requirement for a certain factor - soil supply for a certain factor)/(content of a certain factor in fertilizer () × fertilizer utilization rate in the current season ())

The utilization rate of fertilizers varies greatly. According to experiments, the general utilization rate of organic farmyard manure in the season is about 30%, the utilization rate of nitrogen fertilizers in the season is about 40-50% (calculated as 40), and the utilization rate of phosphorus and potassium fertilizers is about 30%. 30～40 (based on 30).

For example, how much fertilizer is needed to produce 1,000 kilograms of corn grains per mu?

Assume that the soil nitrogen content during the soil survey is 17 kilograms per mu, and the phosphorus pentoxide is 17 kilograms per mu. 6 kg, potassium oxide is 14.4 kg. The nutrient availability in the soil is 50 for nitrogen, 70 for phosphorus pentoxide, and 30 for potassium oxide. When the average yield per mu in the national fertilizer test is 1,000 kilograms, 2.9 kilograms of nitrogen, 1.2 kilograms of phosphorus, and 2.4 kilograms of potassium are required for every 100 kilograms of grain produced. Calculate the application amounts of urea, superphosphate, and potassium chloride (urea contains 46 available nitrogen, Calcium phosphate contains 16 available phosphorus, and potassium chloride contains 50 available potassium.

According to the above formula:

Nitrogen fertilizer (urea) required amount (kg/acre) = (500/100×2.9-17×50)/(46×40)=32.16( Kilogram/acre)

In the formula, 500/100×2.9 is the nitrogen requirement to produce 1,000 kilograms of corn kernels, 17×50 is the nitrogen supply per mu of soil, 46 is the nitrogen content of urea, and 40 is Urea utilization rate in the current season.

For example, if 2,000 kilograms of manure are applied per acre as base fertilizer, the nitrogen content of the manure is 0.45, and the utilization rate in the season is 30, it is equivalent to 2.7 kilograms of nitrogen (2000×0.45×30), which is equivalent to 5.87 kilograms of urea. The actual consumption of urea per mu is 32.16-5.87=26.29 (kg). The amount of phosphate fertilizer and potassium fertilizer applied can also be calculated according to the above method.

Production practice has proved that under normal circumstances, the amount of fertilizer determined by this method can not only achieve the planned yield target, but also continuously improve soil fertility. It is a relatively simple method.

Okay, if you don’t understand the above formula and feel dizzy, it doesn’t matter. In fact, it is just a formula. Then, after measuring the data in the formula, you can directly insert it to calculate. In fact, if you look carefully, it is quite easy to understand.

Let’s talk about the growth periods of corn during which fertilizer is needed. In other words, corn fertilizer is basically used in the following periods:

1. Base fertilizer. 2000kg-3000kg of organic fertilizer, all phosphate fertilizer, 1/3 nitrogen fertilizer and all potassium fertilizer as base fertilizer or seed fertilizer. It can be applied once into the sowing furrow in combination with plowing and ridging, so that the fertilizer can be applied to the tillage layer of 10 cm to 15 cm. All chemical fertilizers can be used as base fertilizers.

2. Seed fertilizer. The dosage of chemical fertilizer is 2kg-5kg. However, the fertilizer must be separated from the seeds. It is better to fertilize deeply, with a depth of 10 cm to 15 cm. Urea, ammonium bicarbonate, ammonium chloride, and potassium chloride are not suitable for use as seed fertilizers.

3. Top dressing. There are four top-dressing periods for top-dressing: seedling fertilizer, culm fertilizer, panicle fertilizer and grain fertilizer, with the following two periods as the focus:

Stalk fertilizer: Top-dressing within 10 days after jointing can promote stem growth and promote young growth. panicle differentiation. Use 1/3 of the nitrogen fertilizer in the top dressing as jointing fertilizer, combine it with shoveling, and keep the distance between the fertilizer and the seedlings 5 ??cm to 7 cm.

Ear fertilizer: The remaining nitrogen fertilizer is applied at the trumpet stage 10 to 15 days before corn tasseling, which can effectively promote larger ears and more grains, and has a good effect on grain filling in the later period.

Although there are so many periods of fertilization during the growth cycle of corn, the specific fertilization still needs to be determined based on the actual situation. The actual situation of corn during the growth process, fertilizer costs, and labor costs Let's consider it comprehensively. Under normal circumstances, it is more common to use one base fertilizer and one top dressing. Top dressing is carried out during the trumpet stage. Multiple top dressings exist in some areas.

What aspects should be paid attention to during the application of base fertilizer and top dressing? Precautions for using corn base fertilizer:

Base fertilizer is also called base fertilizer, including various fertilizers applied before and during sowing. The amount of base fertilizer applied and its proportion to the total amount of fertilizer vary depending on the type of fertilizer, soil, sowing period, etc. The base fertilizer should be mainly organic and slow-acting fertilizers, with appropriate combination of quick-acting chemical fertilizers.

1. Select the standards for corn bottom fertilization. According to the fertilizer requirements and characteristics of corn growth, compound fertilizers with high nitrogen, low phosphorus and high potassium should be used. Generally, the nitrogen content is about 20, the phosphorus content is about 10, and the potassium content is about 15; it is not suitable to use nitrogen, phosphorus and potassium. Use a balanced compound fertilizer as base fertilizer.

In addition, according to the fertilizer demand pattern and characteristics of corn, the use of high-potassium fertilizers can increase the stress resistance of corn and promote the weight gain of corn in the later period, so as to achieve the purpose of increasing yield.

2. Base fertilizer should be applied heavily in combination with top dressing during the corn growth period. Apply enough base fertilizer at one time, because the corn growth period is long, it will cause the corn to lose fertilizer in the later stage to varying degrees, affecting the yield; in addition, applying base fertilizer at one time, the dosage is large, it is easy to burn the seedlings, and will affect the whole corn seedlings, so it should be Corn base fertilizer and top dressing combined.

3. Compound fertilizer with balanced nitrogen, phosphorus and potassium should not be used as base fertilizer. The amount of nitrogen, phosphorus, and potassium required by any crop will not be balanced. Therefore, the application of a balanced compound fertilizer of nitrogen, phosphorus, and potassium will cause an excess of one of the nutrients, causing a waste of nutrients and inhibiting the crop. The absorption of other nutrients cannot achieve better fertilization effects, and the investment is needlessly increased.

4. It is best not to apply diammonium phosphate alone as base fertilizer. Corn bottom fertilization is a three-component compound fertilizer, which contains three elements: nitrogen, phosphorus, potassium and some trace elements. Diammonium phosphate is a binary compound fertilizer, which only contains two elements: nitrogen and phosphorus. The growth of corn requires three elements: nitrogen, phosphorus, and potassium, and the demand for potash fertilizer is large. Therefore, when choosing corn base fertilizer, you should choose a three-component compound fertilizer with higher potassium content. If diammonium phosphate is applied, it is best to use it in conjunction with potassium fertilizer.

5. Apply fertilizer 10-15 cm deep and ensure that the seed fertilizer is separated by 8-10 cm to avoid burning seeds and seedlings.

Precautions for top dressing of corn:

The fertilizer applied during the growth period of corn is called top dressing, which mainly provides the fertilizer required for the peak of corn fertilizer absorption. There are three peaks of fertilizer absorption in the life of corn, namely the jointing stage, the trumpet stage and the tasseling and silking stage. After corn enters the jointing stage, the growth of the vegetative body accelerates, tassel differentiation is in progress, and female ear differentiation is about to begin. The requirements for nutrients are increasing day by day. Therefore, timely application of joint fertilizer can generally achieve the effect of increasing yield. If the base fertilizer is sufficient, the top dressing can be appropriately controlled and the time can be later; when the land is barren, the amount of base fertilizer is small, and the plants are thin, more fertilizer should be applied early and it should be applied early, accounting for 20 to 30% of the top dressing amount. When the soil fertility is low or the base fertilizer and oral fertilizer are insufficient, the joint fertilizer should be applied when the 6 leaves are unfolded.

1. Look at the soil and topdress. Top dressing depends on the nature of the soil. For low-lying and alkaline lands, acidic or physiologically acidic fertilizers such as ammonium nitrate, ammonium sulfate, and superphosphate should be used as top dressing; for acidic soils, alkaline fertilizers such as urea and ammonium bicarbonate should be used as top dressing. For soils with poor water and fertilizer retention capabilities, For sandy loam soil, non-volatile ammonium nitrate or urea should be used as top dressing.

2. Top-dress according to the situation. Due to different conditions such as soil quality, fertilizer and water conservancy, even if the same variety is sown at the same time, the growth conditions will be different. There are plots with strong seedlings and plots with weak seedlings. Even the corn growth conditions in the same plot will be different. Therefore, there should be some differences when applying fertilizer. The specific method is: top-dress chemical fertilizers in strong seedling plots; in addition to top-dressing chemical fertilizers in weak seedling plots, decomposed human manure and cake fertilizers must also be top-dressed; weak seedlings in strong seedling plots should be given a partial diet and be fertilized more Topdressing can help weak seedlings quickly rejuvenate. Cultivating should be carried out in time after top dressing.

3. Watch and fertilize. At present, corn top dressing is customarily based on nitrogen fertilizer. After nitrogen fertilizer is applied to the soil, it quickly decomposes into nitrate nitrogen, ammonium nitrogen and amide nitrogen, and exists in a free state. If the soil cover is too shallow after top dressing, nitrogen will reach the surface and the corn plant can only absorb about 20%. If applied about 10 cm deep and covered with soil in time and compacted tightly, the absorption capacity can reach more than 60%. In view of this characteristic of nitrogen fertilizers, shallow application, open application or application with water should be avoided to prevent fertilizer waste.

4. Top dressing at a later date. Do not topdress too early in the seedling stage to make the corn seedlings thicker and stronger; do not topdress too late during the formation of male and female ears to prevent premature aging; topdressing in the later stage should be timely and appropriate to prevent greed and late maturity.