What is micronutrient fertilizer and how to use it? Explained clearly in one article

Micronutrient fertilizer refers to fertilizers that supply trace elements to plants. Common ones include copper fertilizer, boron fertilizer, molybdenum fertilizer, manganese fertilizer, iron fertilizer, zinc fertilizer, etc., and they are mainly some inorganic salts and oxides. The use of micronutrient fertilizer is very broad, from grain crops to oil crops, cash crops, fruits, vegetables, etc., and it has varying degrees of promoting effect on almost all crops.

1. What is micronutrient fertilizer?

Amino acid micronutrient fertilizer uses plant amino acids as the matrix, takes advantage of their huge surface activity and adsorption and retention capacity, and adds nutrients required for plant growth and development such as nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, etc., forming an organic complex through chelation and complexation. This kind of fertilizer can not only maintain the slow release and full utilization of major elements, but also ensure the stable and long-lasting effect of trace elements. It enhances plant respiration, improves plant oxidation-reduction processes, and promotes plant metabolism.

Amino acid micronutrient fertilizer can promote photosynthesis and the formation of chlorophyll, and has an obvious promoting and activating effect on biochemical processes such as oxide activity, enzyme activity, seed germination, and root growth and development.

2. How should micronutrient fertilizer be used?

1. Boron fertilizer

Crops sensitive to boron fertilizer include rapeseed, sugar beet, etc. The commonly used boron fertilizer is borax. Boron fertilizer is mainly applied by spraying, and can also be used as a base fertilizer and topdressing, and is generally not used for seed treatment.

Base application. It is suitable for soils severely deficient and moderately deficient in boron. Use 0.5 kg of borax per 667 sq m. If boric acid is used, the amount should be reduced by 1/3. Mix with 10-15 kg of fine dry soil or fully mix with nitrogen, phosphorus, and potassium fertilizers before application. When applied in bands, it should be applied to one side of the seeds and should not be in direct contact with the seeds. The fertilizer effect generally lasts for about 3 years.

Foliar spraying. Generally, boric acid is used at a concentration of 0.1%, and borax at a concentration of 0.2% (fruit trees can use a concentration of 0.2%-0.3%). Use 50-70 kg of fertilizer solution per 667 sq m each time, and spray 2-3 times from the seedling stage to the vigorous growth stage, with an interval of 7-10 days each time.

2. Zinc fertilizer

Crops sensitive to zinc fertilizer include rice, corn, etc. The commonly used zinc fertilizer is zinc sulfate, which can generally be applied as a base fertilizer, topdressing, foliar spraying, seed dressing, and seed soaking.

Base application. It is suitable for crops that are plowed before sowing. Apply 1-2 kg of zinc sulfate per 667 sq m (1 mu), mix with 10-15 kg of fine dry soil (or organic fertilizer), and apply to the soil before sowing. Base application has residual effect and generally lasts for about 2 years.

Topdressing. Use 1-1.5 kg of zinc sulfate per 667 sq m, mix with 10-15 kg of fine dry soil, and apply in bands or holes from the seedling stage to the jointing stage.

Foliar spraying. The foliar spraying concentration of zinc sulfate is 0.1%-0.3%. For wheat it is 0.1%, for corn 0.2%, and for rice and fruit trees 0.1%-0.3%. Spray wheat once each at the jointing stage and booting stage; spray corn once each at the seedling stage and jointing stage. For soils severely deficient in zinc, spray once more at the large trumpet stage. The spray volume is 50-75 kg per 667 sq m.

Seed dressing. Use 4-6 g of zinc sulfate per kg of seeds. First dissolve the zinc sulfate in water. Generally, the fertilizer solution accounts for 7%-10% of the seed weight. Spray it evenly on the seeds and sow after drying in the shade.

Seed soaking. Soak millet seeds in a 0.02%-0.05% zinc sulfate solution for 6-8 hours; rice seeds should first be soaked in clean water for 1 day, then soaked in a 0.1% zinc sulfate solution for 24-48 hours.

3. Molybdenum fertilizer

It is mainly used for leguminous crops such as soybean and peanut and for wheat. The commonly used molybdenum fertilizer is ammonium molybdate, which can be used for seed dressing, seed soaking, and foliar spraying, and is generally not used as a base fertilizer.

Seed dressing. Use 1-3 g of ammonium molybdate per kg of bean seeds. Generally, the fertilizer solution accounts for 25%-30% of the seed weight. Too much solution can easily cause the seed coat to fall off, affecting sowing and emergence. Ammonium molybdate must first be dissolved in hot water before use.

Seed soaking. It is not suitable for large seeds such as peanut and soybean, and is mostly used for rice, cotton, and green manure seeds. Generally, soak seeds in a 0.05%-0.10% ammonium molybdate solution. The weight ratio of seeds to solution is 1:1. Soak for 12-24 hours, remove, dry in the shade, and then sow.