Foliar fertilizer knowledge

1. Classification of foliar fertilizer products in my country

According to different classification standards, the commonly used foliar fertilizers can be divided into the following types.

According to product dosage form: it can be divided into two types: solid (powder, granule) and liquid (clear liquid, suspension).

According to components: it can be divided into macroelement, medium element, trace element foliar fertilizer and water-soluble foliar fertilizer containing amino acid, humic acid, alginic acid, sugar alcohol and so on.

According to function: It can be divided into two categories: nutritional type and functional type. Nutritional foliar fertilizer is formulated with one or more of macronutrients, medium and micronutrient elements, and its main function is to provide and supplement crop nutrition in a targeted manner to improve crop growth; functional foliar fertilizer is composed of Inorganic nutrients are mixed with plant growth regulators, amino acids, humic acid, alginic acid, sugar alcohols and other biologically active substances or fungicides and other beneficial substances. Among them, various biologically active substances have a stimulating effect on plant growth. , Pesticides and fungicides have the effect of preventing diseases and insect pests, and beneficial substances also stimulate and improve the growth and development of crops. Therefore, this type of foliar fertilizer combines the functionality of some additives with the supplementation of inorganic nutrients, thereby achieving a synergistic and promoting effect.

The following is a brief introduction of various types of foliar fertilizers according to the function and function of foliar fertilizers.

(1) Large element foliar fertilizer

This type of foliar fertilizer contains one or more of three elements of ammonia, phosphorus and potassium. Among them, nitrogen fertilizers generally use organic nitrogen sources such as amide nitrogen, ammonium nitrogen, nitrate nitrogen or amino acids. The raw materials of the products are generally selected to use urea, ammonium nitrate, potassium nitrate, ammonium sulfate, ammonium chloride, nitric acid, amino acids, etc.; the phosphorus source is mainly orthophosphate, metaphosphate, polyphosphate, etc., and dihydrogen phosphate is generally used in production. Potassium, dipotassium hydrogen phosphate, ammonium phosphate (monoammonium phosphate, diammonium phosphate), phosphoric acid, and some metaphosphates and polyphosphates, etc.; potassium nitrate, potassium dihydrogen phosphate, potassium sulfate, etc. are generally used as foliar fertilizers for potash fertilizers product raw materials.

(2) Medium element foliar fertilizer

Generally refers to foliar fertilizers containing calcium, magnesium, silicon and other ingredients. Among them, calcium fertilizers mainly use water-soluble inorganic calcium salts and chelated calcium, and the raw materials of the products can be selected from calcium chloride, calcium nitrate, calcium ammonium nitrate, calcium acetate, and calcium chelated with organic compounds such as EDTA, citric acid, amino acids, and sugar alcohols. ; Magnesium fertilizers mainly use water-soluble inorganic magnesium salts, generally magnesium chloride and magnesium sulfate; water-soluble silicon fertilizers mainly use sodium silicate (mainly sodium metasilicate and sodium metasilicate pentahydrate) as the silicon source. It is easy to react with calcium, magnesium, zinc, iron and other ions to form flocculent precipitates. Therefore, it is generally used alone in foliar fertilizers.

(3) Trace element foliar fertilizer

In my country's agrochemical market, there are generally two types: elemental element type and compound element type. Generally, soluble inorganic salts and chelated trace elements are used as raw materials. Copper, Iron, Zinc, Manganese, Boron, Molybdenum

Table 1 Common types of raw materials for trace elements

Functional foliar fertilizer

(1) Plant growth regulator type foliar fertilizer

In addition to nutrients, this type of foliar fertilizer adds substances that regulate plant growth. Generally, the types of growth-promoting regulators such as gibberellin, triacontanol, sodium nitrophenolate, DA-6, and naphthalene acetic acid (sodium) are used as the main components. The main function is to regulate the growth and development of crops. mid-term use. With the development of the foliar fertilizer market, the application of plant growth regulators has achieved tremendous development. Because of its obvious effect, quick effect and low cost, it is valued by many manufacturers. However, we suggest that manufacturers should consider the differences in crops, regions, climates, and farmland management when applying regulators, and do not blindly add regulators to achieve a real yield increase effect. It is also necessary to choose products with guaranteed quality. Prevent adverse effects on crops.

Table 2 Plant growth regulators commonly used in foliar fertilizers

At present, there are several kinds of regulators commonly used in production.

(2) Foliar fertilizer containing natural active substances

This type of foliar fertilizer generally contains fermentation or metabolites extracted from natural substances (such as seaweed, straw, animal hair, peat, weathered coal, etc.) to produce amino acids, humic acid, nucleic acids, alginic acid, sugar alcohols and other substances . These substances have the functions of stimulating crop growth, promoting crop metabolism, and improving crop resistance to stress.

①Amino acid foliar fertilizer

There are two sources of amino acids, animals and plants. Plant-derived amino acids mainly include fermented products such as soybeans and cakes, as well as scraps of soy products and vermicelli; animal-derived amino acids mainly include leather, hair, fish meal and scraps of slaughterhouses. The process of converting raw materials into amino acids is also different. The simplest is the acid hydrolysis process. The hydrochloric acid solution with a concentration of 4-6mol/L is commonly used to hydrolyze the material for a certain period of time in proportion, and then neutralize it with ammonia or other alkaline substances. After the PH value, it is the original solution; the more complicated is the biological fermentation method. The compound bacteria are commonly used to ferment the material under certain conditions for 4-6 weeks. After the fermentation liquid is refined, it is processed into a water-soluble fertilizer containing amino acids.

At present, most of the amino acid fertilizers sold in my country are soybean meal, cottonseed meal or other ammonia-containing agricultural and sideline products. The compound amino acids obtained by acid hydrolysis are mainly pure vegetable protein. Such amino acids have good nutritional effects, but poor biological activity; while the amino acids produced by biological fermentation are mainly glycolysis and biodegradation of proteins, and some new active substances are produced by fermentation, such as similar nucleotides, indole Acid, gibberellic acid, fulvic acid, etc., have strong biological activity, can stimulate crop growth and development, improve enzyme activity, and enhance disease resistance and stress resistance. It has a certain effect on rooting, promoting growth, and protecting flowers and fruits.

②Alginic acid foliar fertilizer

The active substance of seaweed fertilizer is extracted from natural seaweed, the main raw material is fresh seaweed, generally large economical algae. Such as Chen algae, sea cysts, kelp and so on. Its production processes include chemical extraction, fermentation, low-temperature physical extraction, etc. Generally speaking, the seaweed extract treated by physical methods has high plant activity and is rich in vitamins, seaweed polysaccharides and various plant growth regulators, such as growth It can stimulate the production of active factors in crops and regulate the balance of endogenous hormones.

At present, the development of seaweed agricultural products has gone through three stages: rotten seaweed - algal ash (powder) - seaweed extract. The extraction process of seaweed extract is roughly as follows: by screening suitable fresh seaweed varieties, using mechanical methods, no contact with any chemical reagents, no high temperature over 45 ℃, no dehydration and freezing, just high-pressure foaming to break the cell wall content It is released and concentrated to form a seaweed essence concentrate, which greatly retains the natural active ingredients of seaweed.

There are seaweed organic fertilizers prepared by fermentation in China. The process is as follows: (1) Fermentation: algae (containing an appropriate amount of water) + biological strains, mixed evenly, put into a fermenter for fermentation, and appropriately adjusted according to the temperature in the tank (including water , air, temperature, etc.); (2) leaching: the fermented product, add the leaching agent, add a certain amount of water and stir well. (3) Dehydration: the extract is dehydrated, nitrogen, phosphorus, potassium and trace elements are added to the liquid part, and the liquid fertilizer is obtained after concentration; the solid part is dried and pulverized and granulated to become organic fertilizer.

There are three methods for the use of seaweed fertilizer in my country: foliar spraying, soil application, and seed soaking. Among them, foliar application is the most effective and broad-spectrum application method. It can stimulate the development of root system and the absorption of nutrients, and significantly improve the resistance of crops such as disease resistance, salinity resistance, low temperature and other stress resistance.

③Foliar fertilizer containing sugar alcohol

Natural sugar alcohol is the primary product of photosynthesis, which can be extracted from plant phloem, and its content in plant phloem juice is much higher than that of amino acids. Sugar alcohols can be used as carriers of nutrient elements such as boron and calcium, carrying mineral nutrients in the phloem of plants and transporting them quickly. At the same time, sugar alcohols have good wetting and osmotic effects. The nutrient elements chelated by sugar alcohol can be quickly absorbed and utilized by crops, and the effect is better than that of chelated fertilizers such as citric acid and amino acid. Sugar alcohol series micro-fertilizers were introduced to the international market in 2001. At present, sugar alcohols are mainly used in the food industry in my country. In recent years, they have also been widely used in the chemical industry. The products on the market are mainly sugar alcohol calcium.

④Foliar fertilizer containing humic acid

Humic acid includes coal humic acid and biochemical humic acid. Coal humic acid refers to humic acid or fulvic acid and its salts extracted from coal, characterized by relatively stable structure and composition, but different activities in different places of origin. Coal humic acid mostly uses lignite and weathered coal as raw materials, and is extracted with benzene or benzene monoalcohol solvent to obtain soluble asphalt and insoluble residue, and the residue is treated with 0.5% sodium hydroxide solution to obtain soluble humic acid-base The solution is treated with 5% hydrochloric acid solution and acetone in turn to separate fulvic acid, palmitic acid and humic acid. Biochemical humic acid is a humic acid-like substance produced by inoculating and fermenting waste straw and bagasse as raw materials. It is an extremely complex mixture system, containing a variety of enzymes and almost all amino acids, trace elements, vitamins, and sugars. And nucleotides, etc., so its effect is the result of the joint action of various components, but the proportion and content of humic acid in the components are the highest, and it is still named humic acid and fulvic acid. Comparing coal humic acid and biochemical humic acid, the former is easy to obtain raw materials and low cost, but the product has low hardness, high hygroscopicity, and is easy to flocculate with metal ions such as calcium and magnesium, which brings disadvantages to practical applications. Biochemical humic acid is better in water solubility, physiological activity, resistance to calcium and magnesium ions and divalent salts, and its soluble pH ranges from 1 to 14. But at present, most of its fermented products are straw fermentation products, and the main component is humic acid. At present, the commonality and characteristics of humic acid and biochemical humic acid detection and analysis, and the definitions of the two have not been clearly explained. At present, coal humic acid is mostly used as a raw material for fertilization in the market, and high content of humate is also used in foliar fertilizers, while biochemical fulvic acid is the main additive in foliar fertilizers. The main function of humic acid foliar fertilizer is to stimulate crop growth, promote root development, reduce leaf stomatal opening, reduce water transpiration loss, and increase plant drought resistance.

⑤ Fertilizer type foliar fertilizer

In foliar fertilizer, in addition to nutrients, a certain amount of different types of pesticides and herbicides will be added. It can not only promote the growth and development of crops, but also have the functions of preventing and controlling pests and weeds. It is a type of fertilizer that combines pesticides and fertilizers. It can usually be divided into special fertilizers for weeding, special fertilizers for insecticides, and special fertilizers for sterilization. However, the demand for nutritional regulation of crops and the occurrence of pests and diseases are not necessarily at the same time. Therefore, when developing and using medicated fertilizers, the drug resistance of different crops and the occurrence rules, habits, and climatic conditions of different crops should be comprehensively considered according to the growth and development characteristics of crops. and other factors, try to avoid drug damage.

⑥Wood vinegar (or bamboo vinegar) foliar fertilizer

In recent years, wood vinegar or bamboo vinegar produced in the production process of charcoal or bamboo charcoal has also appeared on the market as raw materials. Foliar fertilizer with added nutrients. Generally, in the process of burning wood or bamboo wood, the gas generated by high temperature decomposition is collected, and the liquid substance obtained after cooling at room temperature is the original liquid. Wood vinegar contains minerals such as K, Ca, Mg, zn, Ge, Mn, Fe, etc. In addition, it also contains vitamins B1 and B2; bamboo vinegar contains nearly 300 kinds of natural organic compounds, including organic acids, phenols, alcohols, ketones, aldehydes, esters and trace amounts of alkaline components. Wood vinegar and bamboo vinegar were first used in Japan and are widely used. There are also relevant production standards. In my country, the research on this aspect started late, and the production of the two has no national standard, but the related products have been put on the market. According to experimental research, wood vinegar can not only improve the yield of rice, but also improve the ability of rice to resist pests and diseases.

⑦ Rare earth type foliar fertilizer

Rare earth elements refer to the 14 elements of the lanthanide series in the chemical periodic table and scandium and yttrium with similar chemical properties. Rare earth elements for agricultural use usually refer to light rare earth elements in which lanthanum, cerium, neodymium, praseodymium, etc. are radioactive, but the radioactivity is weak and the possibility of pollution is small. The most commonly used is cerium rare earth nitrate. my country has started the research and use of rare earth fertilizers since the 1970s, and its role in plant physiology is not clear enough. Now it is only known that after applying rare earth elements on some crops or fruit trees, it will increase the leaf area, increase the Dry matter weight, increase chlorophyll content, increase sugar content, and reduce acid content. Because its physiological function and effective application conditions are not very clear, it is generally believed that the effect can only be exerted under the conditions that the crops are not lacking in large, medium and trace elements.

⑧Beneficial element type foliar fertilizer

In recent years, some foliar fertilizers containing selenium, cobalt and other elements have been developed and applied. And the application effect is very good. Such elements are not essential nutrients for all plants, but are necessary or beneficial for the growth and development of some plants. Limited by its raw material toxicity and high cost. less application.

Development Status and Application Prospects of Foliar Fertilizers

Since my country began commercial production of foliar fertilizers in the 1980s, my country's foliar fertilizer market has developed

faster. According to incomplete statistics, there are 3,000 to 4,000 enterprises involved in the production of foliar fertilizers in my country, with a wide variety of products and various names. The market competition is quite fierce. The following table shows the common types of foliar fertilizers in the current market in my country. Table 3 The main types of foliar fertilizers in the agricultural market

Because foliar fertilization has many advantages, it has become an indispensable fertilization technology and measure in production. The foliar fertilizer formula should also take into account the differences in crops, soil, climate and other conditions, and develop and use special foliar fertilizers with strong pertinence and high nutrient absorption efficiency. With the development of modern agriculture and fertilizer science and technology, the application of foliar fertilizers has begun to develop in the direction of diversification, pertinence, and environmental protection, and the development of products also tends to be high-concentration, serialized and multi-functional. We must increase scientific research efforts to promote the production and application of foliar fertilizers in my country, and to promote foliar fertilization technology to play a more and more important role in agricultural production.

The following five situations require foliar fertilizer

1. When the root system of the crop is senescent and the absorption capacity is weakened

In the late growth stage of annual crops, the root vigor declines and the ability to absorb fertilizer decreases. If you want to apply fertilizer to crops, the method of root application cannot meet the needs of crops. At this time, it is suitable to use foliar spray fertilizer.

2. When crops have nutrient deficiency

In the process of crop growth, when it has shown some nutrient deficiencies, if soil fertilization is used, it will take a certain period of time for the nutrients to be absorbed by the crops, and the deficiency symptoms of crops cannot be relieved in time.

At this time, if foliar fertilization is used, the advantages of fast absorption of foliar fertilizer can be fully exerted, so that nutrients can quickly enter the plant body through the leaves and solve the problem of lack of nutrients. For example, when vegetables lack certain trace elements, the plants are dwarfed, and the leaves turn yellow and green. If the foliar spray of Haifanwo amino acid foliar fertilizer is used at this time to supplement these trace elements, these deficiency symptoms can be alleviated in time. The soil topdressing fertilizer has good effect and high utilization rate.

3. When the growth of crops is affected by the adverse environment

When the soil environment is unfavorable to the growth of crops, such as excessive water or drought, and the soil is too acidic or alkaline, the absorption of nutrients by the root system of the crops will be blocked, and the crops need to recover quickly. Foliar amino acid foliar fertilizer can quickly supplement nutrition and meet the needs of crop growth and development.

4. When supplementing medium and trace elements quickly

Some fertilizers, such as phosphorus, iron, manganese, copper, zinc, etc., are easily fixed by soil colloid adsorption if used for root application, reducing the effect of use. The use of foliar spraying is not limited by soil conditions, and has the advantages of less fertilizer use, quick effect, high utilization rate, strong stability, and environmental protection.

5. When soil fertilization is difficult to operate

For the crops covered with plastic film and the plots without drip irrigation belts, it is difficult to use soil topdressing when the amount of base fertilizer is insufficient. need.

However, some deep-rooted crops have relatively little absorption of some nutrient elements. If traditional fertilization methods are difficult to apply to the root system, the fertilizer effect cannot be fully exerted, while foliar spraying can achieve better results. Foliar fertilization can make crops better absorbed and utilized, which not only saves the amount of fertilization, but also reduces the pollution of soil and water sources. It is an effective fertilization technology that kills two birds with one stone.

The following three periods are prohibited from using foliar fertilizers

1. Prohibited to use during flowering period

Crops should not be sprayed with foliar fertilizer during the flowering period. The flowering period is the stage of pollination and fruiting. Fertilization during this period is easy to burn flowers, which is not conducive to normal pollination and reduces yield.

2. It is forbidden to use in high temperature in the afternoon

Foliar fertilizer is a high-content nutrient solution component. If foliar spraying is carried out in high temperature weather, it will cause nutrient evaporation, and the nutrient concentration will also decrease in rainy season, both of which significantly reduce the utilization rate of foliar fertilizer.

3. It is forbidden to use when the seedlings are not slowed down

In the seedling stage of crops, most crops are just beginning to germinate, or foliar fertilizer cannot be sprayed immediately after transplanting, because the crops themselves are not only fragile, but also not so adaptable to external conditions. Generally, spraying nutrient solution can easily lead to The phenomenon of burning seedlings and burning leaves is not conducive to the normal growth of seedlings.

When to use foliar fertilizer

The quality of foliar fertilization effect is directly related to temperature, humidity, wind force, etc. Foliar spraying should be done before 9:00 am on a windless and cloudy day, or on a cloudy day with high humidity and low evaporation, preferably in the afternoon After 4 o'clock, if it rains 3-4 hours after spraying, supplementary spraying is required, and amino acid foliar fertilizer with strong adsorption capacity can be selected, and there is no need to re-spray after 10 minutes of rain.