Common Fertilization Technology questions and answers for crops!

What are the essential nutrients of plants?

There are 17 kinds of nutrients necessary for plant growth and development: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), boron (B), zinc (Zn), copper (Cu), molybdenum (Mo), chlorine (Cl), nickel (Ni). Among them, carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur 9 elements need a large amount, called a large number of elements; Iron, manganese, boron, zinc, copper, molybdenum, chlorine, nickel 8 elements need less, called trace elements. Nickel is a recently identified essential element.

How to improve plant root absorption effect?

Plant roots absorb nutrients mainly by their large roots. Such as a mature rice, the root has 200 to 300 roots, more up to 600 to 700, each root there are many branches, the tip of the branch root is the root hair, is the absorption organ of the plant, absorb water, inorganic salts and small molecular organic matter.

Once the root system of the plant has developed, it has the function of absorption. If you want the plant to absorb more nutrients, you should let the plant take more roots, only developed roots, root vitality is strong, in order to absorb more nutrients.
Because plant roots need good breathing conditions to absorb nutrients, the roots also need to maintain sufficient oxygen.
In the production, through deep soil, tilling and thinning the soil, increasing fertilizer (especially humic acid fertilizer), reasonable drainage and irrigation, increasing ground temperature, hormone treatment and other measures, so that plants as soon as possible and establish a huge root system and robust plants, so as to achieve the purpose of high yield and quality.

What is the relationship between soil fertility preservation and fertility supply and fertilization?

Soil fertility retention refers to the ability of soil to absorb and retain nutrients. Soil fertility refers to the ability of soil to release and supply plant nutrients. Good soil should be fertilizer and fertilizer coordination, can meet the needs of crops for nutrients at any time.

The soil with heavy texture and more organic matter content has good fertilizer retention performance, and the fertilizer applied is not easy to lose, but the fertilizer supply is slow, and the effect is slow after fertilization.
The soil with large sand and low organic matter content, the applied ammonium sulfate, urea and other fast-acting fertilizers are easy to be lost with rain or irrigation water, and such soil "produces small seedlings, does not produce old seedlings", although the fertilizer supply performance is good, but no durability, and the crop yield is not high.
Therefore, fertilization should be targeted at different soils, and fertilization measures are also different.

For soils with poor fertility protection and low organic matter content, in addition to more organic fertilizer in the base fertilizer, the application of chemical fertilizer should be "a small number of times" to avoid "burning seedlings" and nutrient loss caused by excessive fertilization at one time, and to prevent premature aging caused by late defertilization.

For soil with good clay or organic matter content, due to good fertilizer retention, the amount of fertilizer can be more at one time, and it will not cause "burning seedlings" and nutrient loss. But such soil "produces old seedlings, not small ones."
In the early stage of crop growth, it is necessary to use seed fertilizer or early topdressing to promote early growth, and to control the amount of fertilizer, especially nitrogen fertilizer, in the middle and late stage of growth, so as not to cause fruitlessness and reduce production.

How to forecast fertilization according to weather conditions?
Crop growth and fertilization effect are closely related to weather conditions. Photosynthesis requires light energy, and sugar produced by photosynthesis is the energy source for the respiration of roots. Insufficient energy will affect the absorption of nutrients by roots.
Therefore, in the case of insufficient light, the absorption of nitrogen, phosphorus, potassium, calcium, magnesium, manganese, and other mineral nutrients is significantly reduced.
Temperature affects both the conversion of fertilizer into the soil and the uptake of nutrients by the roots. If the irrigation temperature of rice is too low, rice blast is easy to occur, because low temperature affects the absorption of silicon and potassium in rice. When the watering temperature of tomatoes in protected areas is lower than 7℃, it is easy to produce a large number of hollow fruits.
On the one hand, water can accelerate the dissolution of fertilizer and promote the absorption of nutrients by crops. On the other hand, if there is too much water, the ventilation is poor, which is not conducive to nutrient absorption and will cause nutrient loss.
In practice, judging fertilization according to weather changes is a complicated empirical technique.
If phosphorus and zinc deficiency occurs in rice solution in low temperature years in early spring, phosphorus and zinc fertilizer should be added in time.
In the season of poor illumination, potash fertilizer should be properly added to improve the utilization of light energy by crops.
In drought years, rape solution boron deficiency, vegetable solution calcium deficiency, pay attention to timely supplement borax and calcium fertilizer.
In the rainy season, it is easy to cause the loss of effective iron in the soil, and it is necessary to pay attention to timely supplementation.

How to improve the effect of fertilizer prevention?
Reasonable fertilization can not only promote crop growth, but also reduce the occurrence of diseases. For example, in the jointing and heading stage of wheat, 1% and 3% superphosphate spray on the leaf surface, respectively, can improve the resistance to wheat stripe rust and reduce the incidence.
The resistance of rice to blast, rice sheath blight, cotton wilt, potato late blight and tomato spot blight could be improved by applying potassium fertilizer. Copper can improve the resistance of tomato to leaf mold and beet brown spot

To improve the purpose of fertilizer disease resistance, we should pay attention to the following three aspects:

1. Re-apply the formula of soil testing and balanced fertilization

Organic fertilizer, inorganic fertilizer and biological fertilizer should be applied together. The combination of large amount of elements and trace elements can enhance the disease resistance of the plant.

2.  Increase the application of organic fertilizer and biological fertilizer

Organic and biological fertilizers contain a large number of beneficial microorganisms, which have certain antagonistic effects on diseases, especially soil-borne diseases.

3. Improve soil pH value

Many soil diseases are sensitive to soil pH. For example, acidic soil is prone to fungi and root-knot nematodes, and the application of slightly alkaline humic acid fertilizer can reduce the occurrence of fungi and root-knot nematodes.

How to diagnose plant deficiency disease quickly?
The physiological effects of different nutrient elements and their mobility in plants are different. Therefore, there is a certain regularity in the location and symptoms of deficiency.
Such as lack of nitrogen, phosphorus, potassium, magnesium, in the plant body can be reused nutrients, lack of symptoms first appear on the old leaves; Calcium, zinc, iron, manganese, sulfur is not easy to move in the body, and the symptoms of lack often appear on new tissues.
In the same condition that symptoms appear on old leaves, nitrogen or phosphorus deficiency may be present if there is no plaque, and potassium, zinc or magnesium deficiency may be present if there is a plaque.
In the case of symptoms starting from new leaves, if it is easy to occur top bud death, it may be a lack of boron or calcium, two sulfur deficiency, iron deficiency, manganese deficiency, molybdenum deficiency, copper deficiency, generally will not appear top bud death phenomenon.
To make an accurate diagnosis, it also needs to be determined by testing the nutrients in the plant tissue.

How to improve the effect of serum?
The effect of foliar spraying is closely related to crop variety, spraying position, spraying concentration and spraying time.
1. Types of crops sprayed
Dicotyledonous plants such as cotton, watermelon, cucumber, tomato, apple, grape and so on have large leaf area, thin cuticle, and the nutrient solution in the solution is absorbed. However, the leaf area of rice, wheat, leek, garlic and other monocotyledonous plants is small, and the leaf surface is covered with wax layer, and the nutrients in the solution are difficult to be absorbed, and the spraying effect is relatively poor.
2. Spraying site
The main parts of spraying are young and functional leaves with strong metabolism, while the old leaves are slow to absorb and the effect is poor. Generally speaking, there are more pores on the back of the leaf than on the front, and the solution is easily absorbed, and the back of the leaf should be sprayed as much as possible.
3. Spray concentration
The spraying concentration of different fertilizers has great difference. Urea 0.5% ~ 1%, superphosphate 1% ~ 1.5%, potassium dihydrogen phosphate 0.2% ~ 0.5%, potassium sulfate about 0.5%, trace element fertilizer usually in 0.1% ~ 0.5% action, containing hormone fertilizer absorption times more than 1000 times.
4. Spraying time
The absorption of nutrients by the leaves depends on how long the solution stays on the leaves. At high temperature at noon, the water solution in the solution evaporates, which is not conducive to nutrient absorption. When the dew is not dry, it should not be applied. It is usually advisable to spray after 3 PM.

What should pay attention to Saline-alkali soil fertilization?
Saline-alkali land is the general name of salt land and alkaline land. Salt ground is soil with high chloride or sulfate content, and pH is not necessarily high; Alkaline soils are soils containing carbonate or bicarbonate, which have a higher pH and are more alkaline.
The common characteristics of saline-alkali soil are low content of organic matter, poor physical and chemical shape, harmful ions to plant growth, crop seedling failure, and even dead seedlings.
Pay attention to the following points in saline-alkali soil fertilization:
1. Increase the application of organic fertilizer, control the amount of chemical fertilizer. Fertilizer should be applied "small amounts and multiple times".
2. Saline-alkali land has high potassium content and low phosphorus content. Attention should be paid to supplementing phosphate fertilizer, appropriately supplementing nitrogen fertilizer, and applying little or no potassium fertilizer.
3. Irrigation should be timely after fertilization to reduce the concentration of soil solution.
Because saline-alkali land is not easy to produce seedlings, the application of seed fertilizer should be particularly careful to avoid contact between seeds and fertilizers, affecting germination.

How to distinguish crop deficiency from disease in the field?

In production practice, plant deficiency caused by lack of nutrients is often easily confused with disease, especially yellow leaves, flowers, poor growth and other symptoms caused by viruses and root-knot nematodes are difficult to distinguish.
To distinguish the symptoms caused by deficiency disease or disease, it is generally diagnosed from three aspects.
1. Look for disease centers
In general, diseases caused by pathogenic microorganisms have obvious disease centers, and pathogenic bacteria can be found. The deficiency syndrome has no incidence center and is mainly sporadic.
2. Soil type and nitrogen application level
In general, pathological diseases were not related to soil type, but closely related to nitrogen application level, and diseases often occurred in fertilized fields. Deficiency disease is closely related to soil type, but mostly in poor soil, such as calcareous soil is prone to zinc deficiency, iron deficiency, manganese deficiency disease, and in acidic soil is prone to molybdenum deficiency symptoms.
3. Weather conditions
Pathological diseases often occur in cloudy and humid weather, and less in drought. The deficiency disease often occurs in low temperature or long drought, such as early rice after transplanting low temperature, prone to phosphorus deficiency, zinc deficiency disease, soil drought prone to rape boron deficiency "flower and not fruit", cabbage calcium deficiency "dry heartburn" and other deficiency diseases

What are the unreasonable conditions of vegetable fertilization in protected areas?
Vegetables in protected areas are a closed environment, so they are obviously different from open cultivation. The phenomenon of unreasonable fertilization of vegetables in protected areas is mainly manifested in the following five aspects:
① Excessive fertilization caused soil salinization
Under normal circumstances, in the protected cultivation environment, because it is not lost by rain, the fertilizer utilization rate is about 20% higher than that of the open field, even if the same fertilizer is applied to the open field, it will cause more nutrients. In addition, vegetable farmers unilaterally believe that as long as the increase of fertilization can obtain high yield of the wrong idea is at work, the result is counterproductive.
Excessive fertilization can cause the accumulation of soil salt, which inhibits the absorption of water and nutrients by crops, and causes vegetable crops to suffer, which is prominent in cucumbers, tomatoes, strawberries and other crops.
The fertilizer is not balanced, and the waste of phosphate fertilizer is serious
Many local vegetable farmers are accustomed to using diammonium phosphate, resulting in a large amount of soil phosphorus accumulation, not only causing losses, but also inducing deficiency disease.
(3) Fertilizer is widely applied on the surface, and the utilization rate is low.
(4) A large number of fresh chicken manure input, do not pay attention to the application of biological fertilizer, resulting in a large number of "burning roots", "burning seedlings" phenomenon.
⑤ Large amounts of nitrogen fertilizer, insufficient potassium fertilizer.
To this end, for the fertilization of vegetables in protected areas, it is necessary to:
① Soil testing and formula fertilization. Scientific fertilization is carried out according to soil test results and vegetable yield levels.
② Control nitrogen and increase potassium, balanced fertilization.
(3) Use organic fertilizer, inorganic fertilizer and microbial fertilizer together to increase the application amount and use times of humic acid water-soluble fertilizer.

How to prevent secondary salinization of soil in protected areas?
Different from the open land, once the fertilization management is not good, it is easy to lead to the accumulation of surface salt, which will lead to secondary salinization of soil. The main causes of soil salinization are as follows:
① The protected area is a closed environment, the temperature is high, the water evaporation is large, and the salt dissolved in the water will gather with the evaporation of water to the surface.
At the same time, the protected areas lack rainwater leaching, the soil water movement is small, and the nutrients remaining in the soil are almost not lost, resulting in an increase in surface salt concentration
② The amount of vegetable fertilizer applied in protected areas is much greater than that in open areas. In addition to being absorbed by vegetables, most of these nutrients remain in the soil.
(3) Improper field management measures, such as surface watering, fertilizer spreading on the soil, shallow tillage, etc., will also exacerbate the accumulation of salt to the surface.

To prevent and control soil salinization in protected areas, we should pay attention to the following four points:

① Soil testing formula, balanced fertilization.
② Irrigation and salt washing. During the hot season, the water is flooded every 30 days. For soil with high salt content, flood it with water before planting vegetables. In summer, remove the plastic film and use rainwater to press salt.
③ Use ground cover to reduce evaporation. Using ground mulching film, straw, etc., can reduce the salt by more than 50%.
④ Choose vegetable varieties with strong salt tolerance. The order of salt tolerance in descending order is: broccoli, lettuce, spinach > eggplant, celery > chili > cucumber, and strawberry has the worst salt tolerance.

How to keep fertilizer properly?
Improper storage of fertilizer, easy to appear moisture absorption, caking, and even nutrient loss imagination. Be careful when keeping it.
① Prevention and control of mixed release
When different types of chemical fertilizers are mixed together, the physical and chemical properties are easy to deteriorate. If superphosphate meets ammonium nitrate, it will seriously absorb moisture and caking, resulting in difficult application. Ammonium sulfate mixed with lime will cause volatilization loss. When superphosphate encounters acidic substances, it reduces the availability of phosphorus.
② Anti-breaking bag packaging
If the broken bag fertilizer is loaded with nitrate nitrogen fertilizer, it will be seriously hygroscopic, mushy after water absorption, or even liquid.
③ Fire Prevention
Especially for ammonium nitrate, potassium nitrate and other fertilizers, in the event of high temperature or open fire will decompose oxygen, easy to burn or explosion.
④ Corrosion prevention
Superphosphate contains free acid, ammonium carbide is alkaline, this kind of fertilizer can not be in contact with metal utensils or scales, so as not to be corroded.
(5) Prevention and control of mixed seeds, pesticides, food, especially volatile ammonium carbide mixed with seeds will affect germination, special attention should be paid.