Nitrogen: A Complex Reality

from The Fertilizer Institute | October 3, 2015

4R Consistent, 4R Practices, 4R's in the Media, Implement the 4Rs, Right Place, Right Rate, Right Source, Right Time

By Lara Moody, Senior Director of Stewardship & Sustainability Programs, The Fertilizer Institute

Nitrogen is at the forefront of many conversations in Iowa, but the context to which it is linked is complex. Nitrogen is inanimate.  It does not get to choose a path of good vs. evil, yet that is how many interpret the impacts of nitrogen use. On one hand nitrogen helps feed the world, while on the other it is a source of environmental challenge. As an individual who works within the fertilizer industry on nutrient stewardship and sustainability, discussing the benefits and challenges of nitrogen use is tricky at best. 

Consider these points. Nitrogen is the fourth most common element in the make-up of our human bodies. Nitrogen is a key component of the proteins you, and all plant and animal life need to survive. Nitrogen is a key ingredient in any cropping or plant based system. It benefits my flower and tomato garden. Without nitrogen fertilizer, 50% of the global population would starve, but nitrogen lost from cropping systems has negative environmental impacts. Nitrogen is a component of hypoxic zones in the Gulf of Mexico. Nitrogen can create challenges for drinking water treatment. And, depending on complexing conditions, nitrogen can be lost to the atmosphere as ammonia or as nitrous oxide, a greenhouse gas. 

Compounding the discussion, the outcome of nitrogen added to a cropping system is influenced by many things we cannot control. In a perfect and simplistic world nitrogen is added to the soil, plant roots take up the available nitrogen as they grow, the plant is harvested, the farmer gets a good return on his nitrogen investment, you consume the harvested plant product, and your body gets nutrients that contribute to your good health. 

In the more complex reality, nitrogen is added to the soil as fertilizer, manure, or plant residue. Soil bacteria convert the added nitrogen and the existing organic nitrogen in the soil to inorganic forms useable by the plant. Yet, those forms useable by the plant are subject to additional chemical and microbial transformations in the soil and may be lost thru groundwater, surface runoff, or gases that escape to the atmosphere. Rainfall, temperature, and soil characteristics influence nitrogen movement and transformations in the soil so not all of the applied nitrogen ends up in the harvested plant. Therefore, some of the applied nitrogen is lost from the system at an economic loss to the farmer. As in most biological and natural systems, we do not exert complete control.

In agriculture, because nitrogen is influenced by things we cannot control, it’s our job to influence the factors we can manage. The fertilizer industry recognizes the complexities surrounding nitrogen and other nutrient use, and for that reason we strongly support and actively promote using the 4Rs (using the right fertilizer source, at the right rate, the right time and in the right place) in conjunction with on-farm conservation practices.  The 4Rs are nutrient best management practices focused on keeping fertilizer in the root zone to increase uptake by the crop and decrease risks of loss to the environment.

Preventing nutrients from leaving the crop’s root zone with 4R practices is the first line of defense for preventing losses to the broader environment. Farmers have a vested interest in managing nitrogen to protect their input investment. Here, there is alignment with stakeholders to decrease nitrogen loss. There are many practices in the 4R toolbox, but their selection is site-specific. There is no silver bullet and no “one size fits all” approach. Implementing the 4Rs puts us on a path for continuous improvement and we need everyone on board.

For more information on the 4Rs, visit www.nutrientstewardship.org, follow us on Twitter @4Rnutrients and look for ways to implement the 4Rs in the field. 

This was an original posting on cleanwateriowa.org.