High crop yields often come under scrutiny because of the fertilizer levels needed to produce such yields and because of the perception and reality of the potential environmental impacts of those inputs.
Yet, maintaining food production for the growing world population requires using new technology and intensifying production and management to grow more food on current cropland. Fertilizer is essential for accomplishing this.
Misuse of agricultural fertilizers have undoubtedly occurred, and its impact on the environment needs to be minimized. But it's important to remember to compare the risk of fertilizer application with the benefits for food production.
The time has come to dispel misconceptions and myths about fertilizers and nutrients, and to convey a correct message to a world that's becoming increasingly urbanized and removed from what agricultural production is all about – providing healthy food.
Fertilizers' contribution to the food supply
A survey of U.S. crop production estimated that average corn yields would decline by 40 percent without nitrogen (N) fertilizer. Even greater declines would occur if other macronutrients, phosphorus (P) and potassium (K) were also limited. Numerous long-term studies have also demonstrated the contributions of fertilizer to sustaining crop yields. For example, long-term studies in Oklahoma show a 40 percent wheat yield decline without regular N and P additions. A long-term study in Missouri found that 57 percent of the grain yield was attributable to fertilizer and lime additions.
Similarly, long-term trials from Kansas show that 60 percent of the corn yield was attributable to fertilizer N and P.
Few people appreciate that corn yields have continued to increase in the Corn Belt of the United States without a similar increase in N (the nutrient addition most associated with runoff-related water impairment). In fact, N-use efficiency has increased at least 35 percent in the past 25 years (meaning less N fertilizer is now required to produce a bushel of grain). Remarkably, more corn is being harvested without increasing N fertilizer application rates. Some of this improvement has also come from modern genetics and improved agronomic management.
