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The "role" of trace elements in the reduction of fertilizer can be more sufficient

Time : 2023-07-17 Hits : 105

November 19, 2015 07:46:34 Source: Farmers Daily


Trace element is a chemical element that is found in very low levels in nature. Some trace elements have biological significance and are necessary for the normal growth and life of plants and animals, and are called "essential trace elements" or "micronutrients", usually referred to as "trace elements They are often referred to as "trace elements". The role of essential micronutrients in plants and animals is very specific and irreplaceable. When the supply is insufficient, plants often show specific deficiency symptoms, and crop yields are reduced, quality is lowered, and in serious cases, the yield may be extinguished. The application of micronutrient fertilizers, on the other hand, facilitates yield improvement, as has been confirmed by scientific and production trials.

Quantitatively speaking, essential nutrients in the range of 0.2 to 200 mg/kg (dry weight) are called "micronutrients" for crops. So far, the essential micronutrients for crops have been confirmed as boron, manganese, copper, zinc, molybdenum, iron and chlorine. These elements are called trace element fertilizers when they are manufactured into fertilizers by factories, such as zinc sulfate is zinc fertilizer, borax and boric acid are boron fertilizers, manganese sulfate is manganese fertilizer, ammonium molybdate is molybdenum fertilizer, copper sulfate is copper fertilizer, ferrous sulfate is iron fertilizer, etc.

There are many types of trace element fertilizers, which can be distinguished by element and also by the type of compound.

1、Distinguish by element

There are molybdenum fertilizer, boron fertilizer, manganese fertilizer, zinc fertilizer, copper fertilizer, iron fertilizer, etc. Boron and molybdenum are often anionic, i.e. borate or molybdate; other elements are cations, commonly used as sulfates (such as zinc sulfate, manganese sulfate, etc.).

Trace element fertilizer - ammonium chloride

① boron fertilizer: borax, boric acid, boron mud (boron slag), boron magnesium fertilizer, boron magnesium phosphate fertilizer, boron containing calcium superphosphate, boron containing calcium nitrate, boron containing calcium carbonate, boron containing gypsum, boron containing glass fertilizer, boron containing minerals, boron containing clay

② molybdenum fertilizer: ammonium molybdate, sodium molybdate, molybdenum slag, molybdenum trioxide, molybdenum-containing calcium superphosphate

Zinc fertilizer: zinc sulfate heptahydrate, zinc chloride, zinc oxide, chelated zinc, zinc carbonate, zinc sulfide, zinc ammonium phosphate

④Manganese fertilizer: manganese sulfate, manganese chloride, manganese carbonate, manganese glass, manganese oxide, manganese superphosphate, ammonium phosphate, manganese slag

⑤ Copper fertilizer: copper sulfate pentahydrate, copper sulfate monohydrate, chelated copper, copper slag, copper carbonate, copper oxide, cuprous oxide, copper sulfide, copper ammonium phosphate

(6) Iron fertilizer: ferrous sulfate, ferrous sulfate ammonium, chelated iron, iron sulfate, iron ammonium phosphate

(7) Chlorine fertilizer: calcium chloride, ammonium chloride, potassium chloride

① Easily soluble inorganic salts: are quick-soluble microfertilizers, such as sulfate, nitrate, chloride, etc. Molybdenum fertilizer is molybdate, boron fertilizer is boric acid or borate. ②Inorganic salts with less solubility: are slow-acting microfertilizers, such as phosphates, carbonates, chlorides, etc.

③Glass fertilizer: it is a silicate type powder containing trace elements, which is a glass-like substance melted or sintered at high temperature with very low solubility.

④Chelate fertilizer: It is a natural or synthetic compound with chelating effect, the product of chelation with trace elements.

⑤ Mixed fertilizer: It is a mixed fertilizer made by adding one or more trace elements to nitrogen, phosphorus and potassium fertilizer.

(6) Compound fertilizer: It is a compound made of nitrogen, phosphorus and potassium fertilizer with one or several trace elements.

(7) Industrial waste containing trace elements: it often contains a certain amount of certain trace elements, which can also be used as trace element fertilizer, and is generally slow-acting fertilizer.


In addition, various organic fertilizers contain a certain amount of various trace elements and are a source of trace element fertilizers, but it cannot be considered that organic fertilizers can completely meet the needs of crops for trace elements.

Boron fertilizer: mainly boric acid and borax. They are both white powders easily soluble in water and contain 17% and 13% of boron respectively. Usually, 0.05-0.25% of borax solution is applied to the soil.

Zinc fertilizer: mainly zinc sulfate heptahydrate (ZnSO4-7H2O, containing about 23% Zn) and zinc chloride (ZnCl2, containing about 47.5% Zn). They are both white crystals easily soluble in water. The zinc salts should be prevented from being fixed by phosphorus when applied. Usually 0.02-0.05% ZnSO4-7H2O solution is used to dip the seeds or 0.01-0.05% ZnSO4-7H2O solution is used as a foliar chaser.

Molybdenum fertilizer: commonly used is ammonium molybdate [(NH4)2MoO4], containing about 50% molybdenum, and contains 6% nitrogen, easily soluble in water. It is commonly sprayed with 0.02~0.1% ammonium molybdate solution. It is more effective for legumes and vegetables, and not very effective for gram crops.

Manganese fertilizer: commonly used is manganese sulfate crystal (MnSO4-3H2O), containing 26-28% manganese, is easily soluble in water pink crystal. Generally with manganese fertilizer containing 0.05 ~ 0.1% of the water solution spraying.

Copper fertilizer: commonly used is copper sulfate pentahydrate (CuSO4-5H2O), containing 24-25% copper, is easily soluble in water blue crystals. Generally sprayed with a 0.02-0.04% solution, or 0.01-0.05% solution to dip the seeds.

Iron fertilizer: commonly used green alum (FeSO4-7H2O). Prepare alum into a 0.1-0.2% solution for application.

Trace element fertilizers are mainly inorganic salts or oxides. Some minerals, metallurgical by-products or wastes can often be used as raw materials for trace element fertilizers, and their production methods are the same as those for inorganic chemicals. In addition, there are two forms of micronutrient fertilizers: one is a glassy substance containing micronutrients, made of corresponding inorganic salts or oxides eutectic with silica; the other is a chelate of metal elements, such as copper, iron, manganese and zinc with ethylenediaminetetraacetic acid (EDTA). This chelated form of trace element fertilizer is effective and fast-acting, but it is very costly and has not been widely adopted.

There are two methods of micronutrient fertilizer application: soil application and foliar spray application. Since the application amount per unit area is very small, it must be diluted with a large amount of inert material before application, and uneven application can poison some crops. Trace element fertilizers often need to be mixed with regular fertilizers and applied together. The following methods are usually used


Several methods are usually used:

1. Mixing in the production of macronutrient fertilizer. This method is convenient and economical, and does not produce uneven nutrient levels.

2、Coating the micronutrient fertilizer powder on the surface of the macronutrient granular fertilizer. This operation can be carried out in secondary processing plants and can readily meet the needs of the market. The granular fertilizer is mixed with the micronutrient fertilizer in a small mixer for about 1min, then a small amount of oil, water or aqueous solution of micronutrient salts is sprayed in and the mixing continues while the product remains dry in appearance.

The effectiveness of micronutrient fertilizers is related to the nature of the soil. In alkaline soils, the effectiveness of the fertilizer is reduced, except for molybdenum, which is more effective. For variable elements, the solubility of the reduced state salt is generally greater than that of the oxidized state salt, so the soil is reductive, and the fertilization efficiency of iron, manganese and copper increases. Organic acids in soil organic matter have a cooperative effect on some elements, and iron with the formation of the compound can increase the fertilizer effect of iron, but will reduce the fertilizer effect of copper and zinc.

1, soil fertilization in addition to chemical fertilizers (such as borax, zinc sulfate, manganese sulfate, etc.) and integrated fertilizers, glass fertilizers, slag or offcuts, usually used as a base fertilizer and seed fertilizer. Its application method is: before sowing combined with the ground into the soil, or mixed with nitrogen, phosphorus, potassium and other chemical fertilizers in a uniform application, the application amount depends on the crop and the type of microfertilizer, generally should not be too large. For example, for rice, zinc sulfate is applied 1 kg per mu, borax is generally 0.5 kg to 1 kg per mu, and should be mixed with organic fertilizers such as stable fertilizer evenly basal application, to prevent local harm caused by concentrated application.

2, extra-root fertilizer will be soluble microfertilizer with a certain concentration of water solution, the crop stems and leaves for spraying. The advantage of this method is to avoid the harm caused by uneven fertilizer in the soil, but also at different stages of crop development, according to the specific needs of multiple spraying to improve the effectiveness of fertilizer. Conditional areas can be mechanically operated or aircraft spraying when applied over a large area, with a general spraying concentration of 0.01% to 0.05%.

3, seed treatment before sowing with aqueous solution of trace elements soaked seeds or seed mix, which is one of the most cost-effective use of fertilizer can be greatly saved. Such as boric acid or borax seed soaking solution concentration of 0.01% to 0.03%. Only 5 liters of this solution is used per 500 kg of seed. Soybeans with ammonium molybdate seed dressing, only 10 grams to 20 grams per mu.

China in the 1940s, began to study the impact of trace elements on plant growth and development. 1950s began to study the content of soil trace elements and their morphology. 1960s began to study the application of microfertilizers in production, successively found that soybeans with key fertilizer yield increase alliance, soil boron deficiency, rape flower Li is not real, cotton just and not flower, soil zinc deficiency, rice stiff seedlings sitting neon corn flower white seedlings, targeted Application of zinc, boron fertilizer, yield increase is very significant, greatly promoting the application of micro-fertilizer.

Pay attention to the amount and concentration of application

Crop needs for trace elements is very little, and from the moderate to excessive range is very narrow, so to prevent the microfertilizer with too much. Soil application must also be applied evenly, the concentration to ensure that the appropriate, otherwise it will cause plant poisoning, pollution of the soil and the environment, and even into the food chain, hindering the health of humans and animals.

Pay attention to improve soil environmental conditions

The lack of trace elements is often not due to the low content of trace elements in the soil, but

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