There are three primary types of agricultural fertilizer, namely those that have been enriched with nitrogen, phosphorous, and potassium. These are broad distinctions, and within each category there can be a number of different options, both in terms of strength and presentation. Some fertilizers come as pellets, others as soil-like spread or even a liquid spray. They can be organic or mainly chemically derived, and they usually contain a complicated cocktail of ingredients. The name they’re given is usually according to the element or nutrient that is most prolific or that appears in the highest concentrations. Choosing the right fertilizer is usually as much a matter of farmer or landowner preference as it is about the crop being grown and the natural composition of the soil to begin with.
Nitrogen Fertilizers
One of the most common types of agricultural fertilizer is nitrogen fertilizer, which comes from animal and plant byproducts. This type of fertilizer is most often spread on top of the soil in which plants are growing. Early farmers and those who follow more traditional practices often use raw animal manure, which is perhaps the most natural nitrogen fertilizer. This isn’t always considered sanitary, particularly for commercial food growers, and can also be somewhat inconsistent; the strength and power of the fertilizer often depends on what the animal ate and its digestive health, and the volume can fluctuate too, particularly on smaller farms.
A number of manufacturers sell pre-packaged nitrogen fertilizers that, while usually still involving some manure, have been sterilized and chemically cleaned. The manure is also usually combined with a range of other components and animal products, particularly fish meal, and is normally controlled and tempered to ensure consistent concentrations. Just the same, this sort of fertilizer can be difficult to work with, at least at first; while necessary for plant growth, too much can actually “burn” leaves and roots. New users might wish to consult with a botanist or gardening expert to learn tips and techniques before beginning.
Phosphorous Options
Agricultural fertilizers frequently also emphasize phosphorous. Typically, the included phosphorus comes from steamed bone meal that has been pulverized or is in powdered form, and can come in a variety of concentration levels. As with nitrogen-based fertilizers, it is important that farmers research which concentration of phosphorus is best for the plants they are growing. In many cases, the quality of the soil can also help determine which fertilizer will be used, with weak soils typically needing stronger supplementation and vice versa.
Potassium-Enriched Products
Growers of potatoes, fruit trees, and other potassium-rich produce often look for fertilizers that can help supplement this important nutrient, which can yield larger, more flavorful crops. For best results, planters should usually test their soil to determine the actual potassium levels first, since this isn’t a nutrient that is always lacking in the soil, and isn’t one that all plants need in abundance in any event. Soils that are very sandy typically need the most potassium, while clay soils may need less. Kits that test potassium concentration can usually be purchased at hardware or home improvement stores. People who do not feel comfortable performing these tests on their own can often receive assistant through their local agricultural counsel.
Understanding the Options and the Market
Farmers who are planning to purchase agricultural fertilizer may want to do some research on the company they are planning to buy from before committing to a large purchase. Understanding the exact nutritional composition of the fertilizer, the manner in which it is created, and the overall price are all important considerations. Deciding on a style and application method is also important. Large operations might prefer slow-release capsules that can be spread once or twice a year, while others might get more from an individualized spray or layering system. Farmers should be prepared to spend a significant amount of time researching both the options available as well as the manufactures and their practices before making a decision.