Different Types of Fertilizers: Nitrogen fertilizer, Crop Yields Naturally and Sustainably

Nitrogen-Based Fertilizers

Nitrogen is an essential nutrient for plants, aiding in photosynthesis, protein synthesis, and chlorophyll production. When plants do not receive enough nitrogen, their growth may slow down, leaves may turn yellow, flower and fruit production can decline, and overall crop quality may decrease. Farmers use nitrogen-based fertilizers like urea, ammonium nitrate, sodium nitrate, potassium nitrate, and calcium ammonium nitrate to quickly add nitrogen to the soil. These fertilizers help improve crop growth, enhance leaf size and color, increase crop quality and taste, and offer better protection against pests and diseases.

However, there are some negative effects of using these fertilizers. They can leach into groundwater, increase soil acidity, and pose health risks such as nitrate toxicity to humans and animals. Therefore, it's important to use nitrogen fertilizers with care.

Best practices for using nitrogen fertilizers:

- Apply them at the right time.

- Use the correct quantity.

- Mix them into the soil or irrigate after application.

- Avoid applying them to wet or frozen soil.

- Combine them with organic matter or other nutrients to support soil health.

Phosphorus-Based Fertilizers

Phosphorus is crucial for plants as it helps with energy transfer, photosynthesis, root growth, flowering, and seed development. Phosphorus-based fertilizers are made from phosphate rocks, which are mined and processed into various forms such as superphosphate, diammonium phosphate, monoammonium phosphate, rock phosphate, and bone meal.
These fertilizers are usually applied before planting or during the early growth stages, as phosphorus does not move easily in the soil and needs to be near the roots to be absorbed. Phosphorus-based fertilizers help improve crop productivity and quality, particularly for crops that require large amounts of phosphorus, such as grains, oilseeds, legumes, fruits, and vegetables.

Potassium-Based Fertilizers

Potassium is another essential nutrient for plants, helping to regulate water balance, osmotic pressure, enzyme activity, the opening and closing of stomata (leaf pores), and the movement of sugars and proteins. It also helps plants resist stress and diseases.

Potassium-based fertilizers are derived from potash rocks and processed into forms like potassium chloride, potassium sulfate, potassium nitrate, and potassium-magnesium sulfate. These fertilizers are usually applied to the soil or as foliar sprays during the growing season because potassium moves easily through the soil and can be washed away by rain or irrigation. Potassium fertilizers help improve crop quality and shelf life, especially for crops that need large amounts of potassium, such as potatoes, tomatoes, bananas, grapes, and citrus fruits.

Organic Fertilizer

Organic fertilizers are made from natural materials such as plant or animal waste, for example, manure, compost, fish meal, and seaweed extracts. They provide essential nutrients to plants and also increase organic matter in the soil, improving its structure, water-holding capacity, microbial activity, and biodiversity. Organic fertilizers are applied before planting or during crop growth, depending on their decomposition rate and nutrient release speed. They enhance soil fertility and crop productivity, especially in organic farming, which relies on natural inputs and avoids synthetic chemicals.

Biofertilizers

Biofertilizers are live microorganisms that improve plant growth and nutrition by fixing atmospheric nitrogen, solubilizing phosphorus, mobilizing potassium, or producing plant growth hormones. These include bacteria (e.g., Rhizobia, Acetobacter, and Bacillus), fungi (e.g., mycorrhiza and Trichoderma), and algae (e.g., cyanobacteria and microalgae). Biofertilizers are usually applied to seeds, roots, or soil before planting or during crop growth. They can reduce the need for chemical fertilizers and improve soil health and crop quality.
Slow-Release Fertilizers
Slow-release fertilizers are made from synthetic or organic materials that release nutrients gradually, ensuring that plants receive them as needed. These fertilizers may be coated with substances like polymers or resins (e.g., urea-formaldehyde or sulfur-coated urea), enclosed in capsules or granules (e.g., Osmocote or Nutricote), or mixed with chemicals that slow down nutrient breakdown (e.g., nitrification inhibitors or urease inhibitors).Slow-release fertilizers are usually applied to the soil before planting or early in the growing season. They help reduce nutrient losses due to leaching or evaporation, allowing for more efficient nutrient use and improved crop yields.

Liquid Fertilizers

Liquid fertilizers are water-soluble or suspended nutrient mixtures. They can be clear liquids (e.g., urea ammonium nitrate) or thick mixtures. Liquid fertilizers are typically applied through irrigation systems or sprayed onto leaves. They provide quick and balanced nutrient absorption and can easily be mixed with other agricultural chemicals.

Microbial Inoculants

Microbial inoculants are products containing beneficial microorganisms that enhance plant growth and health. These microbes improve nutrient availability, protect against diseases, or help plants tolerate stress. Examples include biofertilizers, biopesticides (e.g., Bacillus thuringiensis), biostimulants (e.g., Pseudomonas fluorescens), and biocontrol agents (e.g., Trichogramma). These mixtures are applied to seeds, roots, or soil before planting, reducing dependency on chemical fertilizers and promoting plant growth.

Seaweed Extracts

Seaweed extracts are derived from marine algae and contain nutrients like nitrogen, potassium, calcium, and organic compounds such as alginic acid and hormones. These extracts are typically applied to the soil or sprayed on leaves. They enhance plant growth, increase stress and disease resistance, and improve crop quality and yield.

Humic Substances

Humic substances are natural organic materials formed from the decomposition of plant and animal matter in soil. These include humic acid, fulvic acid, and humin. These substances transport nutrients and metals in the soil, improve soil structure, promote microbial growth, and regulate plant hormones and gene expression. Humic substances are applied to soil or sprayed onto leaves and help improve soil fertility and plant growth.

Calcium Fertilizers

Calcium is crucial for plants as it strengthens cell walls, regulates enzyme activity, and facilitates nutrient transport. Calcium deficiency can cause issues like blossom end rot in tomatoes. Calcium fertilizers are available in various forms, such as eggshells, limestone, gypsum, wood ash, bone meal, and calcium nitrate. Eggshells can be crushed and mixed into compost. Limestone provides calcium and magnesium but raises soil pH, while gypsum improves soil structure. Bone meal promotes root growth but may attract animals. Calcium nitrate is a fast-acting fertilizer that supplies calcium and nitrogen to plants but can be expensive and leach out of the soil quickly.

Magnesium Fertilizers

Magnesium is essential for plants because it is a component of chlorophyll, the green pigment that helps plants make food (photosynthesis). Magnesium deficiency can cause yellowing of leaves (chlorosis), so applying magnesium fertilizers is important. Common magnesium fertilizers include dolomite, which is a natural source of calcium and magnesium and raises soil pH, and Epsom salt (magnesium sulfate), a liquid fertilizer that acts quickly without changing soil pH. It improves plant flavor and color, especially for tomatoes, peppers, and roses.

Sulfur-Based Fertilizers

Sulfur is an important nutrient for plants, helping in protein synthesis, chlorophyll formation, and stress resistance. However, sulfur deficiency is increasing due to intensive farming and lower atmospheric sulfur levels.

Types of sulfur fertilizers:

- Sulfate-based fertilizers provide sulfur in an immediately available form that plants can absorb quickly. They are compatible with most soils and crops, easy to use, and chemically stable, though they can be expensive, leach quickly from sandy soils, and increase soil acidity or salt content.

- Elemental sulfur fertilizers contain 90% sulfur by weight and are cheaper than sulfate-based fertilizers. They last longer in the soil and lower soil pH, making other nutrients more available, but they take longer to become useful to plants and rely on soil microbes to break down.

- Liquid sulfur fertilizers are liquid mixtures of sulfur compounds applied through irrigation systems or as foliar sprays. They provide fast and uniform sulfur supply, can be mixed with other liquid fertilizers or pesticides, and quickly correct sulfur deficiencies. However, they are more expensive than solid fertilizers, can corrode or clog irrigation equipment, and have limited long-term effects on soil sulfur levels.

Balanced NPK Fertilizers
NPK stands for nitrogen, phosphorus, and potassium, the three main nutrients for plants. Balanced NPK fertilizers have these nutrients in equal or nearly equal proportions, such as 10-10-10, 15-15-15, or 20-20-20. These fertilizers are suitable for general use and support the growth and development of most crops.

- They provide complete and balanced nutrition to plants.

- They are easy to apply.

- They are readily available and affordable.