The University of California at Davis defines organic as “materials derived from living organisms.” Synthetic fertilizer is defined by the International Fertilizer Association as “any natural or manufactured material that contains at least 5 percent of one or more of the three primary nutrients: nitrogen (N), phosphorous (P) or potassium (K).” Organic fertilizer is a renewable resource, and synthetic fertilizer relies on man-made production.
Organic farming with organic fertilizer is the oldest form of agriculture on earth. Synthetic fertilizers developed alongside chemistry in the early 20th century. A German physicist discovered a process for turning nitrogen in the air into liquid ammonia, which is the basis for synthetic fertilizer. “The availability of synthetic ammonia after 1913 led to many new N fertilizers, but physical quality was poor,” according to a report published by the Soil Science Society of America.
Both organic and synthetic fertilizers rely on mineral content to produce plant growth. N-P-K labels are the industry-standard method of identifying the percentage content of nitrogen, phosphorus and potassium. These are called “macronutrients” because they are needed in the largest amounts by plants. Organic fertilizers make them available in combination with many other trace elements, nutrients and microorganisms. Synthetic fertilizer utilizes chemical processes to create nitrogen from ammonia and combines it with other artificially created nutrients.
Definitions of soil fertility are similar in both the organic industry and the synthetic fertilizer industry. The International Fertilizer Association acknowledges that “the activities of soil organisms are indispensable for high soil fertility and good crop production.” Synthetic fertilizers do not contain or promote the growth of microorganisms. It is the presence of microorganisms that make soil renewable.
Living organisms are present in organic fertilizers but not synthetic fertilizers. Microorganisms are the tiny living creatures that digest plant and animal materials in the soil and create nutrients with their bodies. They release these nutrients into the soil, where they are absorbed by plant roots. It is the tiny living organisms that create plant nutrition. Synthetic fertilizers boost plant growth but do not contribute to plant nutrition.
The synthetic fertilizer industry promotes the idea that synthetics are necessary to meet the world’s growing food needs and that organic practices cannot meet these needs successfully. Recent studies quoted by the Aquinas College Sustainability Program indicate that the organic farming method “yields 10 times the profit with a rise in crop yields and the elimination of the need to purchase expensive chemicals.” The U.S. had 4.8 million acres under organic farming production in 2008.