Types of fertilizers and recommendations for their use

Every experienced agronomist knows that it is nearly impossible to grow a good crop without fertilizers, as they help restore and maintain soil fertility and provide plants with the necessary nutrients. Today, there is a wide variety of plant and soil additives, each with its own characteristics, purpose, and application methods. In this material, we will answer the question of which fertilizers are needed for specific goals, as well as provide recommendations for their use.

There are many myths about the harmful effects of mineral fertilizers. In reality, there is nothing to fear: these are inorganic compounds that contain macronutrients and micronutrients necessary for plant growth and development in easily absorbable forms. There are several types of mineral fertilizers, each with its own action and purpose. We will consider the main ones:

• Nitrogen enables plants to synthesize proteins. It is also necessary for their growth and the formation of green mass. Therefore, nitrogen fertilizers are used at the early stages of plant development to stimulate intense leaf and stem growth. However, it is important to control their dosage, as an excess of nitrogen can slow down flowering and fruit formation;
• Phosphorus supports energy exchange in cells and helps form the root system. Phosphorus fertilizers promote better root development and improve flowering and fruiting. They are recommended for use at the early stages of growth to support root development;
• Potassium regulates the water balance, helping plants survive during droughts and stressful conditions. It also strengthens cell walls, making plants less susceptible to diseases and improving fruit quality. Potassium fertilizers are best applied during the ripening stage to improve crop quality and support plants during stressful periods.

There are also compound fertilizers, which consist of several macronutrients at once (usually a combination of nitrogen, phosphorus, and potassium). They are suitable for most crops and provide plants with balanced nutrition. These fertilizers are often used in intensive agriculture, as they help replenish the deficiency of several elements at once.

The main advantage of the primary types of mineral fertilizers is their fast effect and high availability of nutrients. Plants can absorb the necessary elements almost instantly. Moreover, by using mineral additives, the dosage can be precisely calculated for specific crops and growth stages.

However, this type of fertilizer also has its drawbacks:

• It leaches out of the soil quickly, especially in conditions of heavy rainfall;
• If used incorrectly or overdosed, it can lead to the accumulation of salts in the soil, causing degradation and reduced microbiological activity.

Therefore, it is important to strictly follow the dosage instructions and consider the specific needs of the plants.

Organic fertilizers are natural materials derived from plant or animal sources. All types of organic fertilizers not only provide plants with nutrients but also have a beneficial effect on the soil:

• They improve its structure;
• They help restore its natural balance;
• They enhance water retention and air exchange properties.

This allows roots to grow freely and effectively absorb moisture along with nutrients. Due to their slow decomposition, organic fertilizers provide plants with nutrition over an extended period, supporting stable growth and development. In soils with a high organic content, crops are more drought-resistant and better able to withstand unfavorable conditions.

The most common type of organic fertilizer is manure. It contains a large amount of essential macronutrients and micronutrients for plants, particularly nitrogen, phosphorus, and potassium. Depending on the type of animal, manure may have a different composition and nutritional value. It is applied to the soil in a rotted form, helping to activate its microbiological activity and increase fertility.

Compost is produced as a result of the decomposition of plant residues (leaves, grass, and food waste). The composted mass is rich in humus and micronutrients that are easily absorbed by plants, and it can be used for all types of crops. Compost not only nourishes plants but also makes the soil loose and moisture-retentive.

Green manure (green fertilizers) are plants that are grown specifically for subsequent burying. They are divided into:

• Leguminous (lupine, peas, clover);
• Cruciferous (mustard, radish);
• Cereal (oats, rye).

These plants not only enrich the soil with organic matter but also prevent erosion, improving aeration and moisture retention. Green manure is often used in the fall, after harvest, or in the spring, before the main planting season begins.

If manure or compost is overripe, it will turn into humus-rich humus. This material has a high concentration of nutrients and improves the soil in the long term. It is especially beneficial for depleted soils that need fertility restoration.

Biohumus is the result of organic matter being processed by earthworms. During this process, the organic material is enriched with microorganisms and beneficial enzymes, making it easily absorbable for plants. Biohumus stimulates root development and increases crop resistance to diseases. This fertilizer is considered one of the most environmentally friendly and effective preparations.

Different types of organic fertilizers are most beneficial when applied during the warmer months of the year—either early in the fall or in the spring, when the soil is already sufficiently warmed.

• Fall application usually provides a longer-lasting effect since fertilizers decompose more slowly, allowing beneficial substances to integrate into the humus layer of the soil. This helps with long-term fertility improvement, and by the spring season, when planting begins, the soil is already enriched with nutrients.
• Spring application better supplies plants with nutrients during their active growth period, as organic matter decomposes more quickly under the influence of warmth.

The frequency of application depends on the condition and type of soil. For poor and depleted soils, organic matter is applied annually to restore fertility more quickly. For more fertile soils, the optimal application schedule is once every 2–3 years, with increased dosage as the interval increases.

Unlike other types of fertilizers, microbiological fertilizers are not a direct source of nutrients. Instead, they contain beneficial bacteria that enhance soil biological activity and help plants more effectively absorb nutrients already present in the soil or supplied through organic matter.

Microbiological fertilizers are highly environmentally friendly. They help reduce the use of chemical agents that accumulate in the soil and negatively impact the environment. As a result, these fertilizers are actively used in organic farming and eco-friendly agriculture.

Plants that consume significant amounts of nitrogen, such as legumes, benefit from nitrogen-fixing bacteria (e.g., Rhizobium and Azotobacter). These bacteria absorb atmospheric nitrogen and convert it into forms accessible to plants. They also increase soil nitrogen content, reducing the need for mineral nitrogen fertilizers. Nitrogen-fixing bacteria help plants grow green mass faster and improve crop quality.

Phosphorus, as previously mentioned, is critical for root growth and fruit formation, but it often exists in the soil in poorly soluble compounds. Phosphate-mobilizing bacteria break down phosphorus-containing compounds, making phosphorus more available to plants. Thanks to these microorganisms, the need for phosphorus supplements is reduced.

These fertilizers should be applied to the soil under conditions favorable for microorganisms. The optimal temperature for their activity is between +10°C and +25°C, and the soil should be moderately moist. Overly dry or waterlogged soil reduces the activity of microorganisms and may lessen the effect. Microbiological fertilizers are typically applied in spring or autumn when the soil is in an ideal state for bacterial activity.

Before application, it is important to consider compatibility with other fertilizers, particularly mineral ones, as high concentrations of inorganic substances can suppress bacterial activity.

As the name suggests, organomineral fertilizers are a combination of organic and mineral components, combining the benefits of both categories. Organic components restore soil structure, while mineral components provide rapid plant nutrition. This combination enables both immediate results and long-term benefits, reducing the need for frequent application of other substances.

Organomineral fertilizers offer a comprehensive approach to increasing soil fertility, enriching it with beneficial elements, and supporting plant health throughout the growing season.

These fertilizers come in various forms, including solid granules or tablets, liquid mixtures, and loose powders, making them versatile for different usage conditions.

One natural organomineral fertilizer is sapropel - a sediment formed at the bottom of freshwater bodies. Sapropel consists of decomposed plant and animal remains, as well as organic and mineral particles carried by water and wind. Because of this, sapropel is rich in nutrients and is widely used in agriculture. It is suitable for use in greenhouses, growing ornamental plants, and creating artificial lawns.

The application of organomineral fertilizers follows the same principle as organic fertilizers: they are used in spring or early autumn, adjusted to the growth phases of plants. In spring, they prepare the soil before planting, supporting plant growth in the early stages. In autumn, they help restore the soil after harvest and enrich it with nutrients for the next season. These fertilizers are suitable for both garden and agricultural crops.

Before application, it is essential to assess the needs of the crops and the type of soil:

• On light, sandy soils, fertilizers may need to be applied more frequently as such soils quickly lose nutrients;
• On clay soils, organomineral fertilizers help prevent compaction and improve air and water penetration.

There are many types of fertilizers, all crucial for supplying plants with essential nutrients and maintaining soil fertility. Knowing which fertilizer to use is key:

• Mineral fertilizers provide a quick effect, delivering primary nutrients to plants;
• Organic fertilizers work more slowly but improve soil structure, biological activity, and its water-retention capacity;
• Microbiological fertilizers restore soil microflora, enhance organic matter decomposition, and ensure nutrient availability for plants.
• Organomineral fertilizers combine the benefits of organic and mineral components, offering comprehensive nutrition and long-term soil improvement.

You will find a wide range of products for agricultural and garden crops from the fertilizer supplier Bonaplant. By selecting preparations for integrated use, you can create favorable conditions for plant growth and maintain soil health in excellent condition.