Different Forms of Granular Micronutrient Fertilizer 

Plants and crops require a mix of both macronutrients (like nitrogen, phosphorus, and potassium) and micronutrients. Dry or granular fertilizer is a convenient way to deliver these nutrients. As a fertilizer importer or exporter, you have your pick among granular micronutrient fertilizers to stock. What are the types?

The three forms of granular micronutrient fertilizer are sulphates, oxides, and oxysulphates. Some types of granular fertilizers, like oxides, are somewhat insoluble, while sulphates are completely water-soluble. 

This guide to the types of granular micronutrient fertilizer will explain each of the forms in much greater detail. We’ll also discuss how to apply granular fertilizer and the benefits of doing so. 

Let’s get started!  

The 3 Types of Granular Micronutrient Fertilizer


The first of the three granular micronutrient fertilizer forms is sulphate. This is a polyatomic anion, which means it contains fewer protons than it does electrons. In other words, the charge of an anion is negative.

Some sulphates can be ionic, which simply refers to a molecule or atom that has a net electrical charge. 

Sulphates are a natural resource, but they can also be synthesized and commercialized for industrial applications such as the fertilization of plants and crops. 

Whether sulphates are ionic or anionic, they’re usually very water-soluble. The only exceptions are barium sulphate, lead (II) sulphate, strontium sulphate, and calcium sulphate. In water, these sulphates are far less soluble. 

The type of sulphate most often used to make commercial fertilizers is polyhalite. This hydrated evaporite mineral usually has no color but can sometimes appear gray, white, or even red if it’s exposed to iron oxide. 

Contained naturally in sedimentary marine evaporites, polyhalite contains 17 percent calcium sulphate, six percent magnesium sulphate, 14 percent sulphate of potash, and 48 percent sulphate.

Iron (II) sulphate may be present in sulphate fertilizer as well, as it’s frequently used in plant and crop soil as a type of mineral supplement. 


Next is oxide. An oxide refers to a compound that contains an element as well as an oxygen atom. 

Oxide acts as oxygen’s dianion, which is an anion with two negative charges. Solid oxides are frequently found around the crust of the earth; these usually result when oxygen from water or air becomes oxidized.

For commercial fertilization purposes, metal oxides are common, especially iron oxide. However, some organic compounds can reduce the efficiency of metal oxides. 

As an example, certain types of metal oxide such as silver oxide can become decomposed when exposed to high heat. This is known as thermal decomposition. 

Reactive metals can displace metal oxide if the metals aren’t as reactive. Copper gets displaced by zinc and becomes zinc oxide.

Hydrogen can cause displacement as well, usually leading to the formation of hydrogen oxide. 

Finally, electrolysis can reduce metal oxides, but not all. This type of reduction is applicable only to aluminum oxide, magnesium oxide, calcium oxide, potassium oxide, and sodium oxide. 

For your customers who need to develop soil nutrient levels for a long time to come, they should use an oxide-based granular fertilizer. Keep in mind that oxides are mostly insoluble. 


The third form of granular micronutrient fertilizer we’ll discuss is oxysulphates. 

Oxysulphates are sulphates and oxides combined into one granule. The level of oxides in the fertilizer versus sulphates varies. 

Generally, you can expect oxysulphate granular fertilizer to share some traits of both the separate types of fertilizer it’s comprised of. 

For building nutrients in the soil, oxysulphate fertilizer is one of the better options. This fertilizer is reliable also if crops or plants have nutrient deficiencies that need correction. 

Applying Granular Micronutrient Fertilizer 

The type of micronutrient fertilizer it’s best to use depends on how much of the growing season has passed and the health of the current crops or plants. 

To accumulate micronutrients in the soil fast, use a granular sulphate fertilizer. 

Oxide fertilizer can also generate higher levels of soil nutrients, however, usually not within the same year it’s applied. The effects, as mentioned, are experienced over a longer period. 

That means that if crops had a nutrient deficiency in year one, an application of granular oxide fertilizer alone could not correct that deficiency. 

farmers with crops

How do you test for a nutrient deficiency in crops? You can request a soil test or soil analysis to gauge the levels of manganese, iron, zinc, and copper in the soil.

When manganese levels are anything under 1.0 particles per million or ppm, the soil is deficient in manganese. 

Iron levels in the soil between 2.0 and 4.5 ppm are only okay while a range of up to 2.0 ppm is deficient. The goal is to get a ppm reading of more than 4.5.

Zinc in the soil is considered deficient if the levels are 0.5 ppm or under. At 1.0 ppm, the levels of zinc nutrients are borderline. The goal should be a reading higher than 1.0 ppm. 

Soil is copper-deficient if the levels of copper drop under 0.3 ppm. A decent range is 1.0 ppm, and anything over 1.0 ppm is sufficient. 

The Benefits of Using Granular Micronutrient Fertilizer

Granular micronutrient fertilizer has its advantages, which is something to keep in mind when promoting your fertilizer for importation or exportation. Here are some such benefits of this type of fertilizer.

Usually Slow-Release

Granular micronutrient fertilizer is often slow-releasing. This means the nutrients in the fertilizer will move into the soil gradually. Using a slow-release fertilizer reduces the need to apply again too often. 

Simple Storage

Some types of fertilizer are negatively affected by cold temperatures while other kinds can settle the longer they sit without being opened or used. Granular micronutrient fertilizer does neither, which makes it an excellent choice. 

Affordable When Buying in Bulk

Stocking up on granular fertilizer is an appealing proposition since the costs of bulk purchasing are sometimes lower than buying the stuff in smaller quantities. 

Easier, Neater Application 

Powder fertilizer can get carried away with the breeze while liquid fertilizer can spill and make a mess. Granular fertilizer is easy to apply by comparison. 


When determining which kind of granular micronutrient fertilizer to offer for import or export, you can select between oxides, sulphates, and oxysulphates. 

The granular micronutrients available at OFertilizer are oxysulphates, including iron oxysulphate, copper oxysulphate, zinc oxysuflate, and more. Build nutrients in the soil quickly and treat nutrient deficiencies with OFertilizer’s granular fertilizer.

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