Most Oklahoma soils are limited in major plant nutrients like nitrogen (N) and phosphorus (P). Therefore, many farmers rely on synthetic fertilizers for crop and forage production. Generally speaking, fertilizer is one of the biggest items, other than land, in an annual budget for many farmers and ranchers.
Fertilizer Is Necessary but Costly
The use of fertilizer chemicals is indispensable in a world with a continuously growing human population, but it comes at a monetary and environmental price.
$200 Billion per year estimated health and enviromental damage from man-made N pollution in the United States.
Only about one-third of the applied N and P fertilizers can be found in crops at harvest. The other two-thirds become unavailable to plants through processes in the soil or are lost to the environment through runoff, leaching, eluviation or erosion. This causes problems such as pollution of drinking water, eutrophication and tipping of freshwater and marine ecosystems, toxic algal blooms, and fish kills. For example, there are 6,000 to 7,000 square miles of dead zone in the coastal waters of the Gulf of Mexico at the mouth of the Mississippi River (learn more). In the United States alone, health and environmental damages of man-made N pollution are estimated to be over $200 billion a year.
Phosphorus Reserves Are Limited
Production of N fertilizers is theoretically almost unlimited, as 78 percent of the atmosphere is nitrogen gas that can be chemically or biologically converted to ammonia. However, the future availability of rock phosphates for production of P fertilizers is a potential threat for food security. This is even more so for countries that rely on rock phosphate imports.
It has been estimated that, at the current and projected future use, the known high-quality rock phosphate deposits (found mainly in Northern Africa or China) will only last for several more generations. Each ton of P that reaches and is diluted in the oceans is ultimately lost to mankind, as it takes millions of years for new, minable P deposits to form. In the light of such situations, fertilizer savings and higher fertilizer efficiency are needed especially in agriculture, where more than 90 percent of the produced N and P chemicals are used (Figure 1).
How Science Is Working to Help You Reduce Fertilizer Needs
Scientific research and better management practices are our best bets to deliver much needed solutions to these issues. Plant scientists at the Noble Research Institute pursue different approaches in this regard, including:
- The study and application of specific plant-associated microbes (bacteria and fungi) for better soil nutrient absorption and nitrogen fixation.
- The transfer of biological nitrogen fixation to crop species that are usually not capable to perform this process (“synthetic N fixation”).
- The study of naturally existing genetic variation in major crop and forage species to identify lines with higher nutrient efficiency.
- The study and use of specific genes to improve plant nutrient acquisition from the soil.
Through these efforts, farmers and ranchers will someday be able to use plants with improved nutrient efficiency due to selection, plants with inherent mechanisms that allow them to perform nitrogen fixation, and/or plants that work in association with soil microbes to enhance nutrient absorption and provide nitrogen fixation.
Integrated with improved management practices that enhance soil health and ecosystem function, successes from this work will ultimately reduce farmer and rancher reliance on synthetic fertilizers and mitigate the negative effects of fertilizers on the environment. This would benefit both producers and consumers in the United States and beyond.