Fertilizer

What is Fertilizer?

Fertilizer is a substance, either organic or synthetic, that is added to soil or plant tissues to supply essential nutrients necessary for plant growth.

When soils lack optimal amounts of major nutrients such as nitrogen, phosphorus, and potassium, which ensure healthy plant growth, fertilizers are applied to replenish them.

In modern agriculture, they’re also frequently applied to nutrient-rich soils as a supplement to further boost plant health, growth, and productivity, particularly for high crop yields like wheat.

Which Forms Do Fertilizers Come In?

• Fertilizers come in solid forms (granules, pellets, powders, and crystals), which are widespread, often inexpensive, and easier to handle.
• Liquid forms (solutions, suspensions) are more suitable for foliar application (spraying the leaves) or fertigation, for which you’ll need an irrigation system.
• Anhydrous ammonia is fertilizer in gaseous form; it contains 82% nitrogen and can be directly applied to the soil.

Types of Fertilizers

Organic

Organic fertilizer is derived from natural sources, like animal manure, compost, sewage sludge, and bone meal. They provide a slow yet steady supply of plant nutrients during their decomposition process, are generally safer to the environment due to their organic nature, and they contribute to improving soil structure by increasing microbial activity.

The drawback is that organic fertilizers are less concentrated than their synthetic alternatives and often require larger quantities and a longer period to achieve the same nutrient levels, which can also drive up costs.

Synthetic

Synthetic fertilizer is manufactured through chemical processes. It’s sourced from mineral deposits, gases, or petroleum byproducts. Common examples include ammonium nitrate, muriate of potash, and nitrogen fertilizers. They are cheaper and more concentrated than their organic alternative.

Unless designed to function as slow-release nutrient providers, synthetic fertilizers immediately provide nutrients to plants and lead to rapid growth.

Types of Fertilizers Explained

Nitrogen Fertilizers

• Urea: Among solid fertilizers, urea contains the highest nitrogen amount (46%).
• Ammonium Nitrate: It contains 33–34% nitrogen, evenly split between ammonium and nitrate.
• Ammonium Sulfate: It contains 21% nitrogen and 24% sulfur. It’s often used in alkaline soils as its acidifying effect lowers the soil’s pH.

Phosphorus Fertilizers

• Superphosphate (Single/Triple): This fertilizer contains more phosphorus, which is beneficial to flowering and fruiting plants. Single superphosphate contains about 16–20% of it, while triple superphosphate contains about 46–48%.
• Monoammonium Phosphate (MAP): This fertilizer contains both nitrogen (11%) and phosphorus (52%). Because it’s water-soluble, it’s best for both foliar sprays and soil.

Potassium Fertilizers

• Potassium Chloride (KCl): This is the most widely used potassium fertilizer due to its high potassium content (60–62%) and affordability. However, alternatives should be sought for chloride-sensitive crops.
• Potassium Sulfate: An alternative to KCl, potassium sulfate is used for plants that are sensitive to chloride. It contains sulfur (18%) but less potassium (50–52%).

Compound Fertilizers

• NPK Fertilizer: NPK stands for nitrogen, phosphorus, and potassium, the primary plant nutrients in commercial fertilizers.

Micronutrient Fertilizers

These target specific deficiencies in the soil. Zinc sulfate for zinc deficiency, for example.

Organic Fertilizers

An organic fertilizer can be compost made from decomposed organic matter, animal manure, sewage sludge (when properly processed), and bone meal.

They contain varying amounts of macronutrients and may be less efficient than synthetic fertilizers.

However, they remain among the most affordable and eco-friendly options.

Liquid Fertilizers

Liquid fertilizers can be synthetic (isobutylidene di-urea, for example) or organic (such as fish emulsion) and are designed to be applied through foliar sprays or irrigation systems.

Biofertilizers

Biofertilizers contain living organisms that convert or fix nutrients, produce hormones or vitamins, or build organic matter.

An example is Rhizobium, a type of bacteria that converts atmospheric nitrogen to a form that plants can use.

Slow-Release Fertilizers

These include polymer-coated fertilizers and sulfur-coated urea among others.

They are designed to slowly release nutrients over an extended period of time to prevent overapplication and leaching. They’re more expensive per unit compared to their granular alternatives.

Pros and Cons of Fertilizers

Pros

• Increased Crop Yields: Fertilizers boost plant growth and productivity. They’re employed extensively to ensure higher cash and food crop yields.
• Improved Soil Fertility: Fertilizers replenish depleted essential nutrients in the soil, making it ideal for healthy plant growth. They also enable soils that are naturally low in such nutrients to become capable of cultivating crops.
• Enhanced Plant Health: Nutrients provided by fertilizers can reinforce the plants’ immune system and resistance to pests and environmental stresses.
• Faster Plant Growth: Fertilizers open up the door to quicker harvests and multiple cropping cycles in a year by accelerating plant growth.

Cons

• Health and Environmental Impact: If uncontrolled and overapplied, organic and chemical fertilizers can lead to nutrient runoff and pollute nearby water bodies. They can also be dangerous to humans if not properly handled.
• Soil Degradation: Over-applying fertilizers can alter soil pH and reduce microbial diversity. Over time, it can also make the soil dependent on fertilizers, and without them, it becomes less fertile.
• Nutrient Imbalance: Excessive fertilizer application leads to nutrient toxicity or antagonistic effects, where certain nutrients become toxic to plants or interfere with the uptake and absorption of others.

Check Out These Terms

• What Is Potash Fertilizer?: Learn what potash fertilizers are and how they enhance soil fertility and plant growth!
• What Is Lawn Care?: Learn which activities go into transforming your lawn from a bland landscape to a lush outdoor area!
• What Is Aeration?: Discover why some people dig holes into their soil and what benefits that has for plant growth!