Synthetic fertilizer has many advantages over organic. It contains precisely measured quantities of potassium, nitrogen and phosphorus, allowing growers to accurately correct nutritional deficits in their soil, it is fast-acting, and it is much more nutrient dense than organic fertilizer is. All these advantages, however, come with certain drawbacks.
According to Stanford University, a study by the Proceedings of the National Academy of Sciences (PNAS) found synthetic fertilizers to leach far more nitrogen into the soil than organic, contaminating groundwater. According to the study, apple trees fertilized with synthetic fertilizer leached between 4.4. and 5.6 times more groundwater than organic fertilizer did. Nitrogen in groundwater can harm aquatic life and cause illnesses in people, particularly children.
Synthetic fertilizers can also be harmful to plants. Organic fertilizers release their nutrients slowly as they are broken down by microorganisms, but synthetic fertilizers are already in a form which is usable by plants, and release their nutrients all at once. If plants are overfertilized, this can quickly damage or destroy the roots, damaging or killing the plant. With organic fertilizer, even overfertilizing will rarely cause damage, according to online resource Organic Gardening Guru.
One of the main drawbacks of synthetic fertilizer is its inability to improve soil structure. As organic fertilizer breaks down, it nourishes beneficial microorganisms and recyclers such as worms, which help maintain soil health. it creates new, well-drained soil with good moisture holding characteristics, helping to replenish topsoil lost to erosion. Synthetic soil merely dumps nutrients into the soil, contributing nothing to the long-term vitality of the soil, says Oregon State University Extension.