Fertilizers are substances which provide essential plant nutrients such as nitrogen, phosphorus and potassium in organic or inorganic forms. They may either be organic or chemical. There are several types of fertilizers, learn about them in this article
Modern chemical fertilizers come from various sources and come packaged in bags with three numbers that indicate their guaranteed analysis or grade – one number represents each percentage by weight of nitrogen, phosphate and potash present in that particular bag.
types of fertilizers
There are several types of fertilizers, including:
- Chemical fertilizers
- Nitrogen fertilizers
- Phosphate fertilizers
- Organic fertilizers
Chemical fertilizers
Chemical fertilizers are one of the types of fertilizers and it can greatly boost crop yields with their high levels of nitrogen, phosphorus and potassium content. Used to correct imbalances in soil nutrition as well as provide quick solutions for severe crop problems, their intensive use can also lead to soil degradation and create undesirable reactions in the environment. But responsible use and understanding how chemical fertilizers operate are ways to limit potential side effects.
Fertilizers come in many different forms – natural or synthetic, liquid or dry and with various formulas. Most contain various proportions of major and secondary chemical nutrients like nitrogen (N), phosphorous (P), and potash (K). These three elements, commonly referred to as macronutrients, are necessary for plant growth in large amounts; other elements like sulfur, magnesium and micronutrients may also be included as ingredients of commercial fertilizers.
Ammonium sulfate, one type of nitrogen fertilizer, is a water-soluble white to yellowish-gray crystalline salt that’s ideal for most soils. Another popular nitrogen source is urea – another highly soluble compound that supplies plant-available nitrogen that’s often included as foliar spray for plants that absorb nitrogen through their leaves.
Phosphatic fertilizers such as monoammonium phosphate (MAP) and diammonium phosphate (DAP), both of which contain high concentrations of available phosphorus in soluble form, are widely used chemical fertilizers that provide essential phosphorus to plants with acidophilus needs such as azaleas and camellias.
Read more: Types of Chemical Fertilizers
Nitrogen fertilizers
Nitrogen fertilizers are one of the types of fertilizers and are very important for the soil as nitrogen is one of the essential plant nutrients. Though abundant in both air and natural gas forms, nitrogen must first be converted to something plants can absorb through nitrogen synthesis – where air and natural gas are combined at high temperatures and pressure to produce ammonia which is mixed with phosphorus and potassium to create compound NPK fertilizers (nitrogen-phosphate and potash).
Urea is another source of nitrogen. Enzymes in the soil convert it to ammonium, with some being released back into the atmosphere due to wet conditions; its loss depends on several factors including
- soil pH,
- temperature
- moisture conditions.
Chemicals designed to inhibit nitrification and urea hydrolysis can help mitigate this loss, with popular examples including 1-carbamoyl-3-methylpyrazole (CMP), dicyandiamide and nitrapyrin (2-chloro-6-trichloromethyl pyridine) being the three primary inhibitors. Nitration inhibitors reduce ammonium ions from being formed while urea inhibitors prevent the hydrolytic conversion of urea into ammonia that’s susceptible to evaporation and leaching.
Read more: Fertilizers rich in nitrogen and copper
Organic fertilizers contain nitrogen
- Organic fertilizers contain nitrogen and plant nutrients in lower concentrations, which must be broken down by soil microbes before plants can utilize them.
- Compared to chemical or inorganic fertilizers, organic fertilizers provide fewer nutrients per pound, but they do not create crusty layers on soil surfaces.
- Organic fertilizers promote water movement through soil and help retain moisture levels, while also feeding soil microbes.
- Using organic fertilizers can benefit your soil by enhancing its overall health and productivity.
Phosphate fertilizers
Phosphate fertilizers are one of the types of fertilizers and are very important for the soil as phosphorus is an essential plant nutrient essential to cell development, root development and seed formation. Additionally, phosphorus serves as the energy transfer system in plants allowing photosynthesis and other metabolic processes to take place. Phosphorus comes from rock phosphate mines – unfortunately a diminishing world resource – but is readily incorporated into soils for plant growth promotion; often combined with nitrogen and potassium in bulk fertilizer blends.
The best phosphorus fertilizers are those which are highly water-soluble and readily absorbed by plant roots, typically created through acid treatment of rock phosphate. Their concentration ranges from ordinary superphosphates through to enriched superphosphates and concentrated superphosphates.
Most phosphate fertilizers are created by treating rock phosphate with acid to increase plant availability. Granular products like these can then be combined with other ingredients for customized blends that meet specific crop requirements – commonly wheat, rice and corn but also tea plants, garlic bulbs cotton crops and watermelons are among them.
Read more: Best Starter Fertilizer
Organic fertilizers
Organic fertilizers are one of the types of fertilizers and they come from plant and animal sources and contain greater levels of carbon than their synthetic counterparts, providing plants with steady access to vital nutrients over time. Many organic materials also improve soil structure by increasing water holding capacity in sandy soils or increasing airflow through clay ones, improving both plant growth and aeration capabilities.
Organic materials can often be collected at no or minimal cost from their surrounding environment, including livestock and agricultural residues, composted green waste and recycled bio-waste. Once collected they may either remain raw (manure, grass clippings) or be processed into high-grade organic fertilizers such as blood meal, bone meal, hoof horn meal, fish fertilizer, alfalfa meal or feather meal for use as fertilizers.
Read more: Best Organic Fertilizer
- Organic fertilizers may be safer for the environment than chemical ones
- Organic fertilizers may take more time to use effectively due to microorganisms breaking down nutrients before they are accessible to plants
- Many organic fertilizers have lower nitrogen-to-phosphorus ratios than inorganic equivalents
- Organic fertilizers require more frequent applications per acre