Formulation types and related functions of foliar fertilizer

Foliar fertilizer is for the purpose of foliar absorption, the nutrients needed by crops are directly applied to foliar fertilizer, which is called foliar fertilizer. Foliar fertilizer is a type of fertilizer in which nutrient elements are applied to the surface of crop leaves and play a basic function through the absorption of leaves. Plant leaves have upper and lower layers of epidermis, which are composed of epidermal cells, and the outer side of the cells on the surface is cuticle and wax. it can protect the mesophyll cells under the epidermis to perform photosynthesis, respiration and other functions, not affected by the changes of external adverse conditions, and the leaves also have many tiny stomata. Exercise the function of gas replacement.

Classification of foliar fertilizer products

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

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

3, according to the composition: can be divided into a large number of elements, medium elements, trace elements foliar fertilizer and water-soluble foliar fertilizer containing amino acids, humic acid, alginic acid, sugar alcohol and so on.

3. According to the function, it can be divided into two categories: nutritional type and functional type. Nutritional foliar fertilizer is prepared by one or more of large, medium and micronutrient elements, and its main function is to provide and supplement crop nutrition and improve crop growth. Functional foliar fertilizer is composed of inorganic nutrient elements, plant growth regulators, amino acids, humic acid, alginic acid, sugar alcohol and other bioactive substances or fungicides and other beneficial substances, among them, all kinds of bioactive substances can stimulate plant growth, pesticides and fungicides can prevent diseases and insect pests, and beneficial substances can also stimulate and improve the growth and development of crops. Therefore, this kind of foliar fertilizer combines the function of some additives and the supplement of inorganic nutrient elements, so as to achieve a mutual synergistic and promoting effect.

The function of foliar fertilizer

1. Foliar fertilizer with a large number of elements

This kind of foliar fertilizer contains one or more of ammonia, phosphorus and potassium. Among them, nitrogen fertilizer generally uses organic nitrogen sources such as amide nitrogen, ammonium nitrogen, nitrate nitrogen or amino acids. The raw materials of the products are urea, ammonium nitrate, potassium nitrate, ammonium sulfate, ammonium chloride, nitric acid, amino acid, etc.; phosphorus sources are mainly orthophosphate, metaphosphate, polyphosphate, etc. Potassium dihydrogen phosphate, dipotassium hydrogen phosphate, ammonium phosphate (monoammonium phosphate, diammonium phosphate), phosphoric acid and some metaphosphate and polyphosphate are generally selected in production. Potassium fertilizer generally uses potassium nitrate, potassium dihydrogen phosphate and potassium sulfate as raw materials for foliar fertilizer products.

2. Medium element foliar fertilizer

Generally refers to foliar fertilizer containing calcium, magnesium, silicon and other components. Among them, calcium fertilizer mainly uses water-soluble inorganic calcium salt and chelated calcium, and the raw materials can choose calcium chloride, calcium nitrate, ammonium calcium nitrate, calcium acetate and calcium chelating with organic compounds such as EDTA, citric acid, amino acid, sugar alcohol, etc. Magnesium fertilizer mainly uses water-soluble inorganic magnesium salt, generally choosing magnesium chloride and magnesium sulfate. Water-soluble silicon fertilizer mainly uses sodium silicate (mainly sodium metasilicate and sodium metasilicate pentahydrate) as silicon source, because it is alkaline and easy to react with calcium, magnesium, zinc and iron to form flocculent precipitation. Therefore, it is generally used alone in foliar fertilizer.

3. Trace element foliar fertilizer

There are generally two types of simple element type and compound element type in China's agrochemical market. Soluble inorganic salts and chelating trace elements are generally selected as raw materials.

Functional foliar fertilizer

1. Foliar fertilizer with plant growth regulator.

In addition to nutrient elements, substances regulating plant growth are added to this kind of foliar fertilizer. Generally, gibberellin, triacontanol, sodium nitrophenol, DA-6, naphthylacetic acid (sodium) and other growth regulators are used as the main components, which mainly regulate the growth and development of crops and are suitable for the early and middle stages of crop growth.

With the development of foliar fertilizer market, the application of plant growth regulators has made great progress. Because of its obvious effect, quick effect and low cost, it has been paid attention to by many manufacturers. However, we suggest that manufacturers, when applying regulators, should consider the differences in crop, regional, climate and farmland management, and should not blindly add regulators to achieve the real effect of increasing production. What's more, we should choose to use products with guaranteed quality. Prevent adverse effects on crops.

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

2. Foliar fertilizer containing natural active substances

This kind 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 acid, alginic acid, sugar alcohol and so on. These substances have the functions of stimulating crop growth, promoting crop metabolism and improving crop resistance.

(1) Amino acid foliar fertilizer

There are two sources of amino acids: animals and plants. Plant-derived amino acids mainly include fermentation products such as soybeans, cakes and meals, as well as scraps of soybean products and vermicelli, while animal-derived amino acids mainly include leather, hair, fish meal and slaughterhouse scraps. The process of converting raw materials into amino acids is also different. The simplest process is acid hydrolysis. The hydrochloric acid solution of commonly used concentration 4-6moI/L is hydrolyzed in proportion with the material for a certain period of time, and then neutralized with ammonia or other alkaline substances. After adjusting the PH value, the original solution is obtained. What is more complicated is the biological fermentation method, in which the compound bacteria are often used to ferment the material for 4 min for 6 weeks under certain conditions. The fermentation liquid is extracted and processed into water-soluble fertilizer containing amino acids.

At present, most of the amino acid fertilizers sold in China are soybean meal, cottonseed meal or other agricultural by-products containing ammonia. The compound amino acids obtained by acid hydrolysis are mainly pure plant proteins. These amino acids have good nutritional effect, but their biological activity is poor, while the amino acids produced by biological fermentation, mainly glycolysis and biodegradable proteins, produce some new active substances after fermentation. such as nucleotides, indolic acid, gibberellic acid, fulvic acid and so on, have strong biological activity, which can stimulate crop growth and development, improve enzyme activity and enhance disease resistance and stress resistance. It plays a certain role in rooting, promoting growth, protecting flowers and fruits.

(2) Alginate foliar fertilizer

The active substances of seaweed fertilizer are extracted from natural seaweed, the main raw materials are fresh seaweed, generally large economic algae. Such as Chlorophyta, Cystis aeruginosa, Kunbu and so on. Its production processes include chemical extraction, fermentation, low-temperature physical extraction and so on. Generally speaking, seaweed extracts treated by physical methods have high plant activity and are rich in vitamins, seaweed polysaccharides and a variety of plant growth regulators, such as auxin, gibberellin, cytokinins, polyphenols and antibiotics, which 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-algae ash (powder)-seaweed extract. The extraction process of seaweed extract is roughly as follows: by screening suitable fresh seaweed varieties, using mechanical methods, without contact with any chemical reagents, without experiencing a high temperature of more than 45 ℃, without any dehydration and freezing, but through high-pressure foaming to break the contents of the cell wall to release, concentrate to form seaweed concentrate, thus greatly retaining the natural active components of seaweed.

In China, seaweed organic fertilizer is prepared by fermentation, and the process is as follows:

① fermentation: algae (containing the right amount of water) + biological bacteria, mixed evenly, put into the fermentor for fermentation, according to the temperature in the tank for appropriate adjustment (including water, air, temperature, etc.)

② extraction: the product after fermentation, add extraction agent, and then add a certain amount of water to stir evenly.

③ dehydration: the extract is dehydrated, nitrogen, phosphorus, potassium and trace elements are added to the liquid part, and then concentrated into liquid fertilizer; the solid part is crushed and granulated into organic fertilizer after drying.

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