4R Nutrient Stewardship: Why Now?




The fertilizer industry endorses best management practices based on the use of the right fertilizer source at the right rate, right time and right place to protect the environment and support the efficient production of nutritious, abundant and affordable food.

Graphic courtesy of The Fertilizer Institute


4R Nutrient Stewardship: Why Now?


by Bill Hertz

As farmers wrap up this season’s harvest, they must focus on replenishing the nutrients that support soil and plant health. However, a fluctuating fertilizer supply and demand, combined with dynamic commodity markets, has impacted growers’ nutrient-use decisions. In some cases, growers have reduced or completely suspended use of nutrient applications – especially phosphate and potash. Consequently, research is showing significant depletion of these macronutrients in many states.


The absence of any single nutrient in the soil can limit plant growth, even when all other nutrients are present in adequate amounts. In addition, potash plays a critical role in drought and disease resistance.


Adding to farmers’ challenges is the growing awareness of environmental issues, such as climate change and water quality. Research is underway to determine how a comprehensive set of fertilizer best management practices (BMP) and conservation best management practices may help reduce nutrient pollution and soil erosion.


To help address these issues, the 4R nutrient stewardship system was developed. This peer-reviewed set of BMPs promotes the use of the right fertilizer source at the right rate, the right time and the right place.


The Conservation Technology Information Center (CTIC) board of directors recently adopted the 4R nutrient stewardship system as the basis for managing nutrients at the field level.


The 4R system continues to gain support among agricultural stakeholders. And, now is the time for the 4R nutrient stewardship system to help farmers achieve environmental, social and economic goals.

Farmers are adopting BMPs


Graphic courtesy of The Fertilizer Institute

Precision agriculture technologies, such as global positioning systems, satellite or aerial images, and information management tools help farmers assess the variability of a field and, in turn, allow for a more accurate determination of fertilizer and agricultural input needs.

Variable rate technology allows different rates of fertilization, seeding and secondary application of nutrients. Additional BMPs, including no-till and low-till systems, conservation buffers and nitrate reducers, are being implemented. Cover crops are also being used to hold the soil in place and prevent erosion, while reducing a crop’s overall nitrogen needs through bacterial fixation.


Whether farmers rely upon their own knowledge or the agronomic expertise of a fertilizer retailer, certified crop advisor (CCA), farm manager or extension services specialist, BMPs that incorporate one or more elements of the 4R nutrient stewardship system are maximizing profits per acre, while minimizing impacts on the environment.

Many roles in promoting the 4R system

Each agricultural stakeholder may be tied to the social, economic and environmental objectives supported by 4R nutrient stewardship.


The more precise use of nutrients, timed to when the crop needs them, can result in better economic returns and less environmental loss. We must all work to produce a safe and abundant food supply to satisfy a population rising by an estimated 80 million people per year.


Fertilizer retailers and manufacturers, CCAs and other field-management advisors have the opportunity to promote the 4R nutrient stewardship system through their direct contact with growers. This one-on-one promotion of the right fertilizer source at the right rate, right time and right place is critical to the 4R system being implemented at the field level.


Economic objectives can be realized at the retail and grower levels. By applying precision agriculture technologies and other BMPs that support the 4R system, farmers can apply fertilizer and other crop inputs only where they are needed. This level of precision allows farmers to become more cost-efficient and supports overall soil health, which, in turn, contributes to the social and environmental objectives of 4R nutrient stewardship.


Environmental health and safety is a priority

In the Chesapeake Bay region, researchers are measuring the amount of nitrogen, phosphorus and sediment pollution at sites in the Bay watershed. Following determination of a total maximum daily load (TMDL) for the Bay, project will be implemented to demonstrate best methods to reduce nitrogen, phosphorus and sediment on agricultural and forest lands.


In Florida, stringent nutrient reduction criteria are being contemplated. In the Gulf of Mexico, fertilizers continue to be scrutinized as a primary contributor to hypoxic regions.


Climate change policy discussions at the federal, state and regional levels have increased awareness of fertilizer’s contributions to greenhouse gas (GHG) emissions, as well as the agricultural opportunities that exist to reduce them.


As discussed in Fertilizer Nitrogen BMPs to Limit Losses that Contribute to Global Warming, authored by the International Plant Nutrition Institute (IPNI), properly balanced plant nutrition through BMPs, such as the 4R nutrient stewardship system, will maximize the capture of carbon dioxide through crop photosynthesis and carbon sequestration, while reducing nitrous oxide emissions – a potent GHG.


The 4R nutrient stewardship system will only gain importance as farmers continue to adopt BMPs and as awareness of nutrient-related environmental issues continues to increase.


To meet the needs of all stakeholders, the 4R nutrient stewardship system objectives must be integrated into a coherent system. Now is the time for agricultural stakeholders to adopt and implement the 4R system.


For further information on the 4R nutrient system system, contact the IPNI at www.ipni.net or The Fertilizer Institute at www.tfi.org.


About the writer: Bill Herz is the vice president of scientific programs at The Fertilizer Institute.


The views expressed in the Member's Column do not necessarily reflect the views of the
Conservation Technology Information Center.