High score, please tell me how to use fertilizers and compound fertilizers correctly for corn, rice, wheat, fruit trees, and vegetables? The more detailed the better!

1·Corn

During the entire growth period of corn, each 100kg of grains needs to absorb 2.57kg of pure N, 0.86kg of P2O5 fertilizer, and 2.14kg of K2O fertilizer, which is equivalent to the application of 14.50 kg of ammonium bicarbonate. kg or 5.51 kg of urea, 3.63 kg of diammonium, and 4.09 kg of potassium chloride. However, the relationship between fertilizer application and yield is not a simple multiple. Factors such as soil nutrient supply also need to be considered.

1. Fertilizer ratio and dosage

(1) High fertility summer corn field: yield per mu is greater than 500kg/mu, N 12.86kg per mu, P2O5 4.30kg, K2O10. 70kg (equivalent to 27.56kg of urea or 72.56kg of ammonium bicarbonate, 18.17kg of diammonium, and 20.44kg of potassium chloride).

(2) Medium-fertility summer corn fields: The yield per mu is 400-500 kg/mu, N10.28-12.85kg per mu, P2O5 3.44-4.30kg, K2O8.56-10.70kg (equivalent to Urea 22.03-27.54 kg or ammonium bicarbonate 58.00-72.51 kg, diammonium 14.54-18.17 kg, potassium chloride 16.35-20.44 kg).

(3) Low-fertility summer corn fields: the yield per mu is less than 400 kg/mu, the N use per mu is less than 10.28kg, and potassium-deficient plots are fertilized with 5kg K2O (equivalent to less than 22.03kg urea or ammonium bicarbonate). 58.00kg, potassium chloride 9.55kg).

2. Corn fertilization period and method

(1) Base fertilizer or top dressing in the seedling stage: Apply 2000-3000 kilograms of organic fertilizer per mu; all phosphate and potassium fertilizers and 30-40% of nitrogen fertilizer Apply when corn has 5-8 leaves. It can be applied once into the sowing furrow in combination with plowing and ridging, so that the fertilizer can be applied to a 10-15 cm tillage layer. All chemical fertilizers can be used as base fertilizers.

(2) Top dressing: Use the remaining two-thirds of the nitrogen fertilizer as base fertilizer or top dressing in the seedling stage as top dressing. The focus is on topdressing at the jointing stage and the trumpet stage.

Jointing fertilizer, applied within 10 days after jointing, can promote stem growth and promote the differentiation of young panicles. Use 40% 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 5-7 cm. The remaining 60% nitrogen fertilizer is applied at the trumpet stage 10-15 days before corn tasseling, which can promote larger ears and more grains, reduce the degradation of florets, and also has a good effect on grain filling in the later period.

Top dressing can be applied in strips or holes. The depth of fertilization is about 15 centimeters. It should be covered with soil in time after application and water should be applied in drought.

3. Reasonable application of micro-fertilizer

It is recommended to apply zinc fertilizer. You can mix or apply a large amount of nutrient fertilizer with micro-fertilizer, which can increase production and reduce the "white bud disease" of corn. ".

(1) Soil fertilization can be applied in strips with water, in ditches, in holes or by splashing. The dosage is 1-2 kg of zinc sulfate per mu.

(2) It can be mixed with water to form a dilute solution of a certain concentration. The concentration is generally 0.2%-0.5%. Spray the zinc sulfate aqueous solution at the seedling stage and jointing stage of corn; the seeds can also be soaked in a concentration of Soak in 0.1-0.5% zinc sulfate solution for 12 hours, then dry slightly before sowing.

2·Rice

1. Nutritional characteristics of rice: The growth and development of rice requires 17 kinds of nutrients including carbon, hydrogen, oxygen, silicon, nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, zinc, boron, copper, molybdenum, and chlorine. There is a large relationship between supply and demand. The different nutrients are nitrogen, phosphorus, and potassium. The contents of nitrogen, phosphorus, and potassium in rice plants gradually decrease as the rice grows, but the peak periods of various elements and the degree of decline are different. From the greening stage to the booting stage, the total absorption of various elements increases rapidly.

Since the booting stage, various elements have increased in varying degrees. For nitrogen, 80% of the total amount of the entire growth process has been absorbed by the booting stage, of which phosphorus is 60% and potassium is 82%. The amount of nitrogen absorbed by the plant has two peaks at the tillering stage and the booting stage. The amount of phosphorus absorbed by the plant reaches its peak at the tillering and jointing stages, accounting for about 50% of the total amount. The absorption amount is also higher at the heading stage. Potassium absorption is concentrated in the tillering to booting stages. Since the heading stage, the absorption of nitrogen, phosphorus, and potassium has been weak. Therefore, most of the nutrients required during the grain filling stage are stored in the plant before the heading stage.

Research results on the fertilizer absorption status of hybrid rice in various stages show that the nitrogen absorption in the early and middle stages of growth is basically the same as that of conventional rice. The difference is that hybrid rice also absorbs 24.6% at the earing and maturity stages. This is One characteristic allows the plant to maintain a higher nitrogen concentration and higher photosynthetic efficiency in the later stages, which is beneficial to green ears and yellow ripening and prevents premature aging. Hybrid rice also absorbs 19.2% of potassium after the ears are ready, which is beneficial to strengthening photosynthesis and the operation of photosynthetic products, and improving the seed setting rate and thousand-grain weight.

The nutrient absorption of rice varies according to different yield levels and different growth environments. Each 667m2 produces 500kg of rice and 500kg of rice straw, and absorbs pure N8.5-12.5k2 from the soil, P205 4-6.5 k2, K20 10.5~16.5kg. The nitrogen, phosphorus and potassium nutrient absorption of 100kg grains of rice is about 2ks, which is slightly lower in high-yield fields and higher in low-yield fields; P2050.9kg, with the increase in yield, the absorption of 100kg grains increases; K20 is about 2.1kg. Low-yielding fields are slightly lower.

The nitrogen (N), phosphorus (P205), and potassium (K20) nutrient absorption amounts of hybrid rice formed into 100ks of grain are 2.0kg, 0.9kg, and 3.0kg respectively. The N and P205 absorption amounts are basically the same as those of conventional rice. , K20 absorption is 0.9ks higher than that of conventional rice. Double-cropping rice is a type of rice commonly cultivated in the south of the Changjiang River in my country. It is divided into early rice and late rice. They have the same characteristics: short growth period, high intensity of nutrient absorption, concentrated fertilizer demand and large amount of fertilizer. However, due to different growing seasons, there are also certain differences in nutrient absorption. From transplanting to tillering, early rice absorbs nitrogen, phosphorus, and potassium, accounting for 35.5%, 18.7%, and 21.9% of the total, respectively, while late rice accounts for 23.3%, 15.9%, and 20.5%, respectively. The absorption of early rice is higher than that of late rice, especially Nitrogen; from the differentiation of young panicles to the heading stage, nitrogen, phosphorus, and potassium absorbed by early rice accounted for 48.6%, 57.0%, and 61.9% respectively, and that of late rice accounted for 58.7%, 47.4%, and 51.8% respectively. The nitrogen absorption of late rice The amount increases rapidly; during the fruiting and maturity period, the absorption of nitrogen, phosphorus, and potassium by early rice decreases, which are 15.9%, 24.3%, and 16.2% respectively, while those of late rice are 19.0%, 36.7%, and 27.7%. It can be seen that the absorption of nutrients by late rice in the later period Higher than early rice.

2． Fertilization technology

(1) Fertilization technology for early rice. Early rice fertilization generally adopts the "pre-attack and post-attack" fertilization method, that is, base fertilizer should be applied heavily, tiller fertilizer should be applied early, and ear fertilizer should be applied later. Generally, for medium-fertility plots, 10 to 12 kg of nitrogen (N), 8 to 10 kg of phosphorus (P205), and 5 to 6 k2 of potassium (K20) are applied per 667 m2. The base fertilizer is mainly organic fertilizer with a certain amount of Nitrogen fertilizer accounts for about 70% of the total amount, phosphorus fertilizer is used as base fertilizer, 50% of potassium fertilizer is used as base fertilizer, and 50% is applied as top dressing. The first top dressing is carried out 1 week after transplanting, and the amount accounts for 30% of the total fertilizer amount. Ear fertilizer generally accounts for 10% of the total fertilizer amount, and is mainly potassium fertilizer.

(2) Late rice fertilization technology. Late rice fertilization should adopt the "pre-promotion and mid-control" fertilization method. According to the characteristics of a strong fertilizer absorption peak 2 to 3 weeks after transplanting, 70% to 80% of fertilizer should be used in the early stage. The effect of phosphate fertilizer on late rice is lower than that on early rice. Therefore, if more phosphorus is applied to early rice, late rice can take advantage of the aftereffects of phosphorus and no longer apply phosphorus fertilizer. The effect of potassium application in late rice is better than that in early rice. Potassium fertilizer should be used first in late rice. Generally, 8-10kg of potassium chloride is applied per 667m2, and the ratio of base fertilizer to pre-heading application is 6:4.

3·Wheat

1. Wheat nutritional characteristics

1. Generally, the production of 100kg of wheat grains at medium fertility level requires about 2.5-3kg of nitrogen (N). , phosphorus (P205) 1.0-1.7kg, potassium (K20) 1.5-3.3kg. As wheat yield increases, the absorption ratio of nitrogen, phosphorus, and potassium also increases accordingly. The absorption of nitrogen, phosphorus and potassium nutrients by wheat gradually increases from the seedling stage, tillering stage to jointing stage as the plant vegetative body grows and the root system is established, reaching a peak at the booting stage. Wheat absorbs nitrogen, phosphorus, and potassium nutrients at different rates at different growth stages. There are two peaks in nitrogen absorption. One is from tillering to overwintering. Although the wheat seedlings are small at this time, the amount of nitrogen absorbed during this period accounts for 13.5% of the total absorption, which is a period of rapid population development. The other is from jointing to booting. During this period, the plant grows rapidly and the demand for nitrogen increases sharply. Nitrogen absorption accounts for 30%-40% of the total absorption, which is the period with the largest amount of nitrogen absorption. The absorption of phosphorus and potassium generally increases with the growth of wheat, and the absorption rate increases sharply after jointing. More than 40% of the phosphorus and potassium nutrients are absorbed after booting.

2. Although the absolute amount of trace elements such as zinc, boron, manganese, copper, and molybdenum absorbed by wheat is small, trace elements play a very important role in the growth and development of wheat. According to test data, approximately 9g of zinc needs to be absorbed for every 100kg of wheat produced. In different growth periods, the general trend of absorption is: more before overwintering, the absorption slowly increases during the greening and jointing stages, and the absorption reaches the highest during the heading and maturity stages, accounting for 43.2% of the absorption during the entire growth period. It can be seen that zinc nutrition should be enhanced during the wheat seedling stage and grain maturity stage, otherwise it will affect the tillering and grain fullness of wheat. Manganese has a greater impact on the growth of wheat leaves and stems. The leaves and stems of plants lacking manganese are dark green, and the veins between the leaves are light green. Boron is mainly distributed in leaves and stem tops. Plants lacking boron have a delayed growth period, poorly developed male and female stamens, unable to pollinate normally, and eventually wither and lose fruit.

2. Winter wheat fertilization technology

1. The appropriate dosage of wheat fertilizer. Generally, a field with a yield of 400-500 kilograms per mu should apply 3500-4500 kilograms of organic fertilizer per mu; chemical fertilizers should be applied: 13-15 kilograms of pure nitrogen, 8-9 kilograms of pure phosphorus, and 8 kilograms of pure potassium, which converts to about 28 kilograms of urea and 20 kilograms of ammonium phosphate. kg, potassium chloride 10 kg. (Generally, all phosphorus and potassium fertilizers are used as base fertilizer, 60% of the total amount of nitrogen fertilizer is used as base fertilizer, and 40% is used as top dressing, that is to say, 20 kg of urea, 20 kg of ammonium phosphate, and 10 kg of potassium chloride are applied as the base fertilizer. Top dressing during the jointing period. Apply 5-7 kilograms of urea. If the land is deficient in fertilizer, you can apply about 10 kilograms.) Of course, according to the soil test results, combined with the difference in organic fertilizer usage and target yield, the amount of chemical fertilizer application should be increased or reduced as appropriate. During the wheat heading to grain-filling stages, potassium dihydrogen phosphate (0.4-0.5) aqueous solution can be sprayed on the leaves to increase grain weight, promote maturity, and improve the ability to withstand dry and hot winds.

2. Application of basal fertilizer. "Wheat likes to be rich in the womb, and base fertilizer is the foundation." Basal fertilizer is not only necessary for early emergence of seedlings, cultivating strong seedlings before winter, and increasing effective tillers, but also lays a good foundation for cultivating strong stalks, large ears, and increasing grain weight. For wheat fields with sticky soil, strong fertilizer retention properties, and no irrigation conditions, all the fertilizer can be applied as base fertilizer at one time, commonly known as "one shot". The specific method is to spread the full amount of organic fertilizer and 2/3 nitrogen, phosphorus, and potassium chemical fertilizers on the surface of the land, then plow deeply, and after plowing, spread the remaining fertilizer on the head, and then rake it into the soil. This allows the entire tillage layer to be mixed with fertilizer, which not only facilitates the formation of strong seedlings in the early stage, but also prevents premature aging due to defertilization in the later stage. For sandy soil or irrigated land with poor fertilizer retention performance, a divided fertilization method of heavy application of base fertilizer and clever application of top dressing can be used. That is to say, 2/3 of the nitrogen fertilizer and all phosphorus, potassium, and organic fertilizers are used as base fertilizer, and the remaining nitrogen fertilizer is used as top dressing. Applying seed fertilizer is the most economical and effective method of fertilization. Generally, 2-3kg of urea per 667m2, or 8-10kg of superphosphate, or about 10kg of compound fertilizer can be used.

Micro fertilizer can be used as base fertilizer and seed dressing. When used as base fertilizer, due to the small amount, it is difficult to spread it evenly. You can mix it with fine soil and then spread it on the surface, and then spread it into the soil as you plow.

When dressing seeds with zinc and manganese fertilizers, use 4-5g of zinc sulfate and 4-8g of manganese sulfate per kilogram of seeds, and sow immediately after dressing.

3. Application of top dressing. Skillful application of top dressing is an important measure to obtain high wheat yields. (The time for top dressing should be early, usually before winter. There is often a saying that "outside of the year is not as good as during the year".) Top dressing in spring is moved to the jointing stage. Generally, 5-7 kg of urea per mu is applied to the land. Blocks can be increased to 10 kg. Most of the top-dressing fertilizers are nitrogen fertilizers, but when the base fertilizer is not applied with phosphorus fertilizers and potassium fertilizers, and the soil supply of phosphorus and potassium is insufficient, top-dressing phosphorus fertilizers and potassium fertilizers should be applied appropriately. For high-yield fields with insufficient potassium supply, about 150kg of plant ash can also be spread before winter. For wheat fields with sufficient fertilizer supply, it is important to avoid excessive topdressing of nitrogen fertilizer, and the topdressing time should not be too late. Otherwise, it will easily cause greedy greening and late maturity, resulting in reduced yields.

4. Spray fertilizer outside the roots. Spraying fertilizer outside the roots is an effective fertilization method to supplement the late nutritional deficiencies of wheat. Since it is inconvenient to topdress wheat fields in the later stages, and the absorptive capacity of the root system decreases as the growth period progresses. Therefore, if fertilizer must be applied in the later stages of wheat growth, foliar spraying can be used, which is also an emergency measure to increase wheat production. During the heading stage of wheat, 2% to 3% urea solution can be sprayed. Spraying urea not only increases the thousand-grain weight, but also increases the protein content of the grains. If necessary, 0.3% to 0.4% potassium dihydrogen phosphate solution can also be sprayed, which plays an important role in promoting photosynthesis and strengthening grain formation. The spraying amount of urea and potassium dihydrogen phosphate solution is 250~60ks per 667m. The spraying concentration of micro-fertilizer is generally 0.1%, and the spraying amount is 250kg per 667m. Spraying zinc fertilizer should be carried out at the seedling stage and after heading, and can be sprayed 1 to 2 times. Boron fertilizer can be sprayed during the booting stage of wheat, and manganese fertilizer can be sprayed once at the jointing and flowering stages. The time for spraying fertilizer should be after 4 p.m. when there is no wind to avoid excessive evaporation of water and reduce fertilizer efficiency.

4·Fruit trees

Nitrogen fertilizers are highly mobile in the soil, and shallow application can penetrate into the dense layer of the root system and be absorbed and utilized. The penetration status of ammonium nitrogen fertilizer applied to the soil varies with the precipitation period. For example, when NH4-N fertilizer is applied to a 5 cm soil layer in January, due to precipitation until mid-March, part of it penetrates into the 20 cm soil layer, mostly at 10 cm; from late April to mid-May, part of it penetrates to 30 cm. centimeters, most of them remain in the soil layer of 10 to 20 centimeters. Therefore, the shallow application of nitrogen fertilizer should also consider the rainfall, soil conditions, root distribution depth, fertilization period and fertilizer type in various places. Judging from the production of NO3--N, which is easily absorbed by the roots, in acidic soil lacking organic matter, NO 3--N is not seen in soil layers at different depths before mid-March, and from late April to May In the middle of the year, it started to increase significantly. It can be seen that there is a transformation process from the application of NH4-N to the absorption and utilization by the roots.

The growth and decline dynamics of nitrogen fertilizer are greatly affected by climatic conditions. Judging from the fertilizer effects of various types of nitrogen fertilizers in different soils, rapeseed cake and granular fertilizers are applied to volcanic ash soil, ammonium sulfate and granular fertilizers are best applied to clay soils, and the effects of various nitrogen fertilizers to sandy soils are not ideal.

Phosphate fertilizers have poor mobility in the soil and are easily fixed and converted into water-insoluble sulfates, which are unfavorable for root absorption. According to observations (1957), almost all superphosphate applied to 5 cm of acidic barren soil remained under the surface from January to March; it decreased after April, and there was almost no change below 20 cm. It can be seen that after shallow application of phosphate fertilizer, it is mainly fixed on the soil surface and cannot reach the root distribution layer. Therefore, it is advisable to apply phosphate fertilizer deep into the dense layer of the root system.

my country's Liu Delin et al. (1983) studied the application methods of phosphate fertilizer in Wenzhou dense citrus orchards in red soil mountains and found that: (1) When superphosphate is mixed with pig manure residue, the absorption of 32P by citrus plants in the early stage will be reduced. When superphosphate plus lime or superphosphate lime is mixed with pig manure, the absorption of 32P will increase significantly only in the later stages.

(2) When phosphorus fertilizer is applied shallowly (16.7 cm), it is beneficial to root absorption in the short term. However, as the root system grows, the effect of shallow application becomes worse and worse. The phosphorus content in the leaves is far less than that applied deeply (50 cm). ) treatment; (3) Compared with divided application of phosphorus, the phosphorus content of leaves increased by 8.14 to 20.96, and the fruit yield increased by 25. (4) According to 32P measurement, the fixation of phosphorus in the soil of Wenzhou dense orange orchard was as high as about 70, when When the same amount of calcium, magnesium and phosphorus fertilizer is applied per hectare, the fixation rate can be reduced by 3.

In summary, the additional application of organic fertilizers and lime in orchards on red soil mountains can promote the fertilizer effect of phosphate fertilizers; mixed application of phosphate fertilizers and organic fertilizers is more effective than single application; deep application is better than shallow application; concentrated application The next best thing.

In modern orchard fertilization, special emphasis is placed on comprehensive analysis based on factors such as fruit tree species, environmental conditions and cultivation measures to determine the fertilization period, fertilization time, fertilization method and fertilizer type, in order to achieve scientific fertilization. The purpose of economical use of fertilizers and improving fertilizer utilization efficiency.

2. Commonly used fertilization methods in production

(1) Ring fertilization is also called wheel fertilization. It is to dig a ring-shaped trench slightly outside the crown of the tree with a width of 30 to 50 cm and a depth of 20 to 40 cm. Apply fertilizer into the trench, mix with soil and cover. This method has the advantages of easy operation and economical use of fertilizers, and is suitable for use on seedlings. However, it is easy to cut off horizontal roots when digging trenches, and the scope of fertilization is small, which easily causes the roots to float up and distribute in the topsoil.

(2) Radial trench fertilization is to dig 5 to 8 fertilizing trenches radially under the tree crown, 1 meter away from the main trunk, along the horizontal root growth direction, 30 to 50 cm wide and 20 to 40 cm deep. , apply fertilizer. In order to reduce the large roots, they are cut off because they are shallow inside and deep outside. The location can be changed every other year or every other time, and the fertilizing area can be expanded year by year to expand the root absorption range.

(3) Fertilizing in trenches: Dig trenches 20 to 30 cm deep and 30 cm deep inside and outside the drip line of the tree crown. Applying fertilizer can also be combined with deep plowing. Change location every year. This method is suitable for orchards with wide rows and dense plant cultivation, and is easier to mechanize.

(4) Hole fertilization: Dig 3 to 5 circular holes with a diameter of about 30 cm and a depth of 20 to 30 cm every 50 cm or so outside the drip line of the tree crown. This method is mostly used for top dressing, such as applying liquid nitrogen, phosphorus, potassium fertilizer, human waste, biogas fertilizer liquid, etc., to reduce the contact surface with the soil and avoid soil fixation.

(5) Fertilizing the whole garden. That is, when the canopy of the orchard has been handed over and the root system has covered the entire orchard, first spread the fertilizer on the ground and then dig it into the soil to a depth of about 30 cm. However, due to shallow fertilization, the root system is often induced to float and the root system's stress resistance is reduced. If applied alternately with other fertilization methods, it can complement each other and give full play to the fertilizer effect.

5·Vegetables

1. Fertilizing vegetables: Although crops all need 16 kinds of nutrients, different crops require different amounts of various nutrients. For example: leafy vegetables mainly require leaves, so the effect of applying nitrogen fertilizer is more obvious, so the amount of top-dressing nitrogen fertilizer should also be larger; for fruits and vegetables, since fruits are supplied to the market, in addition to nitrogen fertilizer, phosphorus and potassium fertilizers are needed It also requires more potassium fertilizer.

Various crops have different requirements for various nutrients at different growth stages, and the amount of fertilizer applied is also different. For example: fruits and vegetables, while growing vegetatively, reproductive growth has also begun. Fertilization is effective when the flower buds begin to differentiate, bloom and fruit, and the fruit expands. During the expansion period of tomato fruits, nitrogen accounts for 10% of the total absorption, phosphorus accounts for 17%, and potassium accounts for 5%. At the beginning of harvest, nitrogen accounts for 50% and potassium accounts for 40%. Therefore, vegetable farmers pay special attention to heavy application of fertilizers during the fruit expansion period. . For head-bearing vegetables such as Chinese cabbage, in addition to paying attention to organic fertilizer as base fertilizer, seedling fertilizer is also applied during the seedling stage to promote the strength of the seedlings. When the first leaf ring grows and the seedling stage ends and enters the rosette stage, apply high-quality organic fertilizer to promote root development. When it begins to enter the core-packing period, use fertilizers to promote the expansion and firming of the balls.

2. Fertilize according to the sky: The main climatic factors that affect fertilization are temperature, rainfall, and light. When the temperature is higher, crops grow vigorously and require more fertilizer, which is also conducive to the decomposition and transformation of fertilizer. Therefore, more fertilizer can be applied during the growing season when the temperature is suitable, while less or no fertilizer can be applied during the low-temperature season. Soil moisture conditions also have a great impact on fertilization. Nutrients absorbed by plants must be dissolved in water. When there is appropriate moisture in the soil, it is conducive to microbial activity and material decomposition, and improves the fertilizer effect. Under soil drought conditions, the effectiveness of fertilization is not great; when there is excessive rainfall, fertilizer leaching loss must be considered, resulting in large investment and small returns. Therefore, fertilization must be combined with irrigation and rainfall to fully exert the fertilizer effect. Light is an indispensable condition for photosynthesis of crops. Inorganic salt nutrients are closely related to the progress of photosynthesis and the operation of photosynthetic products. Sufficient light can also increase the temperature and promote plant growth. In this case, more fertilizer is required, so fertilization is more effective when there is sufficient water and good light conditions.

3. Fertilizer application: There are many types of fertilizers used in vegetable production, each with its own characteristics, such as organic fertilizers and inorganic fertilizers, natural fertilizers and chemical fertilizers, solid fertilizers and liquid fertilizers, and macroelement fertilizers. with trace element fertilizers, etc. In vegetable fertilization, organic fertilizers are often combined with inorganic fertilizers, and organic fertilizers are used as base fertilizers and top dressings, while inorganic fertilizers are mostly used as top dressings, and in some cases inorganic fertilizers are used as base fertilizers. There are also some refined organic fertilizers, such as cake fertilizers, which are used after the seedling stage. They are applied in ditches or holes near the vegetable roots, and then covered with soil and watered to meet the needs of rapid growth of crops.

According to the state of fertilizer, it is divided into three types: solid, liquid and gas. Solid fertilizers must be dissolved in water before they can be absorbed by vegetables when applied to the soil; liquid fertilizers, such as ammonia, generally need to be diluted with water before application, or deep application methods should be used and the soil should be covered in time to avoid damage to leaves and plants due to gas volatilization; gas fertilizers It mainly uses carbon dioxide for fertilization and can be used in greenhouses or plastic greenhouses. It has an obvious effect on increasing the yield of melons.

Soil fertilization is generally divided into two types: surface fertilization and deep fertilization. For some fertilizers that are easy to volatilize and need to avoid denitrification, such as ammonium sulfate, ammonium nitrate, ammonium bicarbonate and other nitrogen fertilizers, it is best to apply them deep in the soil to allow ammonium ions to be adsorbed by soil particles to prevent loss. Phosphate fertilizers and potassium fertilizers are in the soil. It moves downward very slowly, so the effect of application on the surface layer is not great. It is better to mix it evenly into the soil layer. In the fertilization of vegetable fields, water-soluble chemical fertilizers are often applied with the irrigation water, which is relatively simple. Especially when the plants grow up and cover the ground, this method of topdressing has a good effect. But sometimes there is a lot of loss and waste, especially when the ground is uneven and the uniformity of fertilization is poor.

When applying chemical fertilizers, in addition to soil fertilization, you can also topdress the roots. When applying fertilizer outside the roots, chemical fertilizers of pure quality and not suitable for burning the leaves should be used. Urea, potassium dihydrogen phosphate, etc. are commonly used on vegetables.

In addition, there are trace element fertilizers, which are mostly used for foliar spraying, mainly because crops have very little need for them. On the other hand, if some trace element fertilizers are applied to the soil, they are easily converted into difficult-to-use fertilizers. The form is absorbed by plants, so external top dressing is often used for crops to utilize. Boron fertilizers, zinc fertilizers, manganese fertilizers, etc. are commonly used on vegetables.

4. Fertilization according to different cultivation methods: Since the seasonality of vegetable production and the balance of supply often conflict, depending on the season, open field cultivation and plastic greenhouses, medium boron, small sheds, and greenhouses are often used. and various cultivation methods such as mulching to produce vegetables. Due to different cultivation methods of the same kind of vegetables, the amount of fertilizer applied varies greatly.