Fertilizers have a significant effect on crop yields. However, some farmers have increased the amount of fertilizer for the pursuit of high-yield blindness, and the more fertilizers are applied, the more serious the soil pollution is, and the production is difficult to increase.
According to estimates, after the fertilizer is applied to the soil, phosphorus can only be used by about 13%, nitrogen is about 25%, and potassium is about 40%. In other words, nearly 80 kilograms of fertilizer per 100 kilograms of fertilizer we apply to the soil is not absorbed by crops.
The main reasons for the low utilization rate of chemical fertilizers are as follows: First, long-term application of chemical fertilizers, soil acidification is intensified, and harmful heavy metals are exceeded, which restricts the absorption and utilization of nitrogen, phosphorus, potassium and trace elements. The second is the unreasonable fertilization habits, such as a large amount of compound fertilizer applied at one time. Because the compound fertilizer contains nitrogen, the fertilization can not reach the root system during the seedling stage, otherwise it will cause the seedlings, but at this time, it is the phosphorus phase, but the phosphorus The mobility of elements in the soil is very small, causing phosphorus deficiency in the seedling stage to affect growth. The peak of nitrogen release is about 15 days after application to the soil, and will become less and less in the future, and nitrogen deficiency will occur later in the crop.
There are four important periods for corn to be fertilized: one is the 3-leaf stage, which is the critical period of phosphorus demand. The absorption rate of phosphorus in this period determines the number of rows of corn. The second is the small trumpet period, that is, when vegetative growth and reproductive growth go hand in hand, it is a critical period of nitrogen demand, and insufficient supply of nitrogen fertilizer will affect corn yield. The third is the large trumpet period, which requires a lot of nutrients in this period, which is the maximum efficiency period for corn to absorb fertilizer. The fourth is the heading stage. When the tassels and ears are not prematurely degraded, the supply of nitrogen will increase the number of grains per corn. Therefore, in order to produce high yields of corn, it is necessary to do a good job of fertilizing on demand in four key periods. At present, most of the seeding is the same as the seed fertilizer. The distance between the general seed and the fertilizer is 5-8 cm. If the special fertilizer for quick-acting corn (mostly high-nitrogen compound fertilizer) is applied, it is easy to cause the rooting of the corn in the third leaf stage. fat. If the controlled release fertilizer is applied, it is easy to release nitrogen fertilizer in the 6-leaf stage of maize, and the yellowing occurs. This period is the critical period of nitrogen, which will lead to the reduction of production, and the supply of nitrogen in the late stage of most controlled release fertilizer is also insufficient.
In addition, the fertilization habit must be changed: one must apply high quality controlled release fertilizer. Second, we must increase the amount of organic fertilizer. Third, it is necessary to apply fertilizer separately. First, 50% of the annual total fertilizer amount is applied to the soil before ploughing, and the remaining 50% is planted into the soil with the seed. In the later stage, no top dressing or a small amount of top dressing is needed to meet the high yield of corn.
According to estimates, after the fertilizer is applied to the soil, phosphorus can only be used by about 13%, nitrogen is about 25%, and potassium is about 40%. In other words, nearly 80 kilograms of fertilizer per 100 kilograms of fertilizer we apply to the soil is not absorbed by crops.
The main reasons for the low utilization rate of chemical fertilizers are as follows: First, long-term application of chemical fertilizers, soil acidification is intensified, and harmful heavy metals are exceeded, which restricts the absorption and utilization of nitrogen, phosphorus, potassium and trace elements. The second is the unreasonable fertilization habits, such as a large amount of compound fertilizer applied at one time. Because the compound fertilizer contains nitrogen, the fertilization can not reach the root system during the seedling stage, otherwise it will cause the seedlings, but at this time, it is the phosphorus phase, but the phosphorus The mobility of elements in the soil is very small, causing phosphorus deficiency in the seedling stage to affect growth. The peak of nitrogen release is about 15 days after application to the soil, and will become less and less in the future, and nitrogen deficiency will occur later in the crop.
There are four important periods for corn to be fertilized: one is the 3-leaf stage, which is the critical period of phosphorus demand. The absorption rate of phosphorus in this period determines the number of rows of corn. The second is the small trumpet period, that is, when vegetative growth and reproductive growth go hand in hand, it is a critical period of nitrogen demand, and insufficient supply of nitrogen fertilizer will affect corn yield. The third is the large trumpet period, which requires a lot of nutrients in this period, which is the maximum efficiency period for corn to absorb fertilizer. The fourth is the heading stage. When the tassels and ears are not prematurely degraded, the supply of nitrogen will increase the number of grains per corn. Therefore, in order to produce high yields of corn, it is necessary to do a good job of fertilizing on demand in four key periods. At present, most of the seeding is the same as the seed fertilizer. The distance between the general seed and the fertilizer is 5-8 cm. If the special fertilizer for quick-acting corn (mostly high-nitrogen compound fertilizer) is applied, it is easy to cause the rooting of the corn in the third leaf stage. fat. If the controlled release fertilizer is applied, it is easy to release nitrogen fertilizer in the 6-leaf stage of maize, and the yellowing occurs. This period is the critical period of nitrogen, which will lead to the reduction of production, and the supply of nitrogen in the late stage of most controlled release fertilizer is also insufficient.
In addition, the fertilization habit must be changed: one must apply high quality controlled release fertilizer. Second, we must increase the amount of organic fertilizer. Third, it is necessary to apply fertilizer separately. First, 50% of the annual total fertilizer amount is applied to the soil before ploughing, and the remaining 50% is planted into the soil with the seed. In the later stage, no top dressing or a small amount of top dressing is needed to meet the high yield of corn.
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