Ammonium nitrate was the most common source of lawn fertilizer nitrogen until price increases starting in 2004 reduced its availability. Ammonium sulfate and urea (livestock urine) are two nitrogen alternatives used as home lawn fertilizer products. They are quick-release forms of nitrogen that produce rapid growth in lawn turf. Ammonium sulfate is a chemical byproduct of steel-making and synthetic fiber production.

Lawns Need Nitrogen

Nitrogen is one of 17 nutrients lawn grass and other plants need. It is the most abundant nutrient available in the atmosphere but it cannot be absorbed by plants until it has been transformed into ammonium or nitrate compounds. Nature accomplishes this through the decomposition process created by bacteria and algae. Commercial lawn fertilizer products use laboratory processes to create water-soluble chemical nitrogen that has a quick-acting effect on plants. Ammonium sulfate is one of the three main sources of chemical nitrogen used as lawn fertilizer.

Lawn Fertilizer Composition

Lawn fertilizers are created from either organic or inorganic compounds. Ammonium sulfate is an inorganic, factory-made compound used as the nitrogen source in commercial N (nitrogen) P (phosphorus) K (potassium) fertilizers. Commercial lawn fertilizer stimulates quick growth in grass turf. Organic lawn fertilizer contains all the 17 nutrients needed by grass lawns of all types and is derived from natural sources. Organic lawn fertilizer is slower-acting than commercial fertilizer, making nutrients available only as they are needed by the growing grass plants. Natural fertilizer may also neutralize overly acidic soil.

Disadvantages of Ammonium Sulfate

Ammonium sulfate used as lawn fertilizer has the disadvantage of creating high levels of acidity in the soil.”It requires approximately two to three times as much lime to neutralize the same amount of acidity as formed by other common N (nitrogen) carriers,” says a report by Ohio State University Extension Agronomist Jay W. Johnson. Overly acidic soil reduces the activity of beneficial microorganisms in the soil, which break down organic matter and create nitrogen in natural processes. If you use ammonium sulfate as a lawn fertilizer, test your soil pH regularly.

Advantages of Ammonium Sulfate

Ammonium sulfate can be stored for longer periods and is not as highly explosive as ammonium nitrate. It contains 24 percent sulfur, which is one of the nutrients plants need. Its cost is not affected by the fluctuating costs of natural gas because it is a byproduct of other industries. It is less expensive than organic fertilizer and other slow-release fertilizer products. It is easily blended with other nitrogen products, such as urea, to make a stable, dry lawn fertilizer.