4R Nutrient Stewardship

Legacy phosphorus is an evolving concept useful in the responsible management of crop nutrition. A cumulative balance of inputs and outputs is part of responsible management of plant nutrition and 4R nutrient stewardship. This cumulative balance can be used to compare fields that have differed in their historical inputs and productivity and identify where current replenishment, deficit, and surplus rates are appropriate. In addition, the legacy concept is also useful for situations in which soil testing is impractical. 

Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz.

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

Fertilizers, particularly nitrogen, comprise a large part of the carbon footprint of crop production. The industry is exploring and applying innovations toward reducing emissions of greenhouse gases arising from the manufacture and use of fertilizers.

Earn 1 CEU in Nutrient Management by reading the article and taking the quiz. 

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

In-season nitrogen applications, when managed effectively, offer a powerful tool for enhancing crop productivity and environmental sustainability. By aligning nutrient availability with crop needs, optimizing application methods, and mitigating potential risks, farmers can achieve better outcomes for both their crops and the environment.

Earn 1 CEU in Nutrient Management by reading this article and taking the quiz. 

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

The principles of 4R nutrient stewardship apply to every plant nutrient. Magnesium (Mg), traditionally considered a secondary macronutrient, is often overlooked. This article reviews the options available for managing magnesium and the benefits you might expect.

Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz. 

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

Sulfur plays several roles in 4R plant nutrition. First, as an essential plant nutrient, it may need to be applied to optimize yields and quality of crops. Second, there may be a need to replenish the sulfur removed from the soil by crop harvests. Third, some forms of sulfur may have additional benefits through their effects on soil pH and on soil nitrogen processes. The three roles combine to support enhanced productivity with lower impacts on the environment. This article reviews basic sulfur nutrition, recent trends affecting the need for fertilizers, and the contribution of sulfur to improving productivity sustainably. 

Earn 1 CEU in Nutrient Management by reading this article and taking the quiz. 

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

Nutrient management, particularly for nitrogen, plays an important role in improving the carbon footprint of crop production. Many programs have recently expanded their offerings or funding levels of incentives to farmers to adopt more climate-smart nutrient management practices. These programs provide opportunities for crop advisers to accelerate adoption among their clients of 4R practices that reduce greenhouse gas emissions and support soil carbon sequestration. The intent of this article is to provide a broad description of the programs available and the practices most likely to be effective.

Earn 1.5 CEUs in Nutrient Management by reading this article and taking the quiz. 

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

The 4R nutrient stewardship framework has brought us closer to improving our nutrient use efficiency. However, given the inherent “leakiness” of the N cycle, it is challenging to increase N use efficiency to optimum levels. Newer fertilizer technologies, like enhanced-efficiency fertilizers (EEFs), are tools that can help achieve this goal. To determine if EEFs should be incorporated into nutrient management programs, growers and crop advisers should consider the various types of EEFs available, their functions within the soil, and the timing of application relative to the crop’s nutrient uptake demand. 

Earn 1 CEU in Nutrient Management by reading this article and taking the quiz.

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

What is a plant nutrient? For many decades, plant nutrients have been defined by the concept of essentiality. More recently, however, 4R nutrient stewardship has been defined as management that produces sustainable outcomes. Some elements provide benefits even if they are not essential. A new definition of what a plant nutrient is has been proposed and is under consideration by authorities in fertilizer regulation. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz.

In recent years, biostimulants and biologicals have gained substantial traction in the marketplace with dozens of products available for growers and consultants to choose from. However, biostimulants vary widely in type and mode of action in the plant. To best understand how some of these products may be tied to soil fertility, a deeper understanding of biostimulants and biologicals is worth acquiring. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz.

Big data and machine learning have the potential to transform agriculture and 4R nutrient management practices. The integration of these technologies empowers farmers to adapt to variable conditions, optimize applications, and minimize environmental impact. While challenges such as data quality must be addressed, the future prospects are promising. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning-Center/Courses.

In 2013, the fertilizer industry in North America launched the 4R Research Fund. Members of the fertilizer industry pledged annual commitments of financial support to research connecting 4R practices to impacts. This article briefly summarizes findings and benefits to the industry that have resulted from the financial support directed towards research. Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Fertilizer use has been a key factor in boosting crop yields worldwide. At the same time, the global use of nitrogen fertilizer is associated with greenhouse gas emissions This article reviews the scope for reducing emissions associated with fertilizer use. It addresses the global scale and recent reports focused on Canada, the United States, and sub-Saharan Africa. It concludes with a review of the advantages and limitations of approaches based on managing nitrogen surplus in crop nutrient budgets and shows how a 4R approach both includes and goes beyond reducing surpluses.

Hypoxia in the Gulf of Mexico is an environmental issue connected to agricultural crop management in the Mississippi River watershed. Programs to improve nutrient stewardship in this watershed aim to improve nutrient use efficiency and reduce losses of nitrogen and phosphorus. Trends since the 1980s show increases in both crop production and the size of the hypoxic zone while the trends in nitrogen surplus have neither increased nor decreased. Provisional flow-normalized river loads of nitrogen are decreasing. While improvements in adoption of 4R management of applied fertilizers and manures have been noted, opportunities for improvement also remain. While 4R practices will not solve the issue on their own, they can make an important contribution when integrated with soil conservation practices and changes to whole farming systems.

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

The use of 4R practices to manage nutrients is critical to support crop photosynthesis and make soil carbon storage an effective proposition for greenhouse gas mitigation. What is required is a delicate balancing act. Increasing primary productivity, reducing wastes, selecting climate-smart sources, and using inhibitors of N₂O emissions are all critical. The strong role of N in the multiple mechanisms of soil C storage underscores the need for integrated consideration of 4R nutrient management in programs that address both the emissions and sinks associated with cropping systems while keeping them productive. 

Climate-smart fertilizers will play an increasingly important role. They fit well into the 4R Nutrient Stewardship concept, which provides an excellent framework for recognizing and rewarding the farmers that adopt their use. Programs, protocols, and policies aimed at reducing the carbon footprint of agriculture need to recognize climate-smart fertilizer use in a 4R framework. 

Nutrients are essential for plant and animal agriculture and comprise a large portion of its outputs. The starting point for assuring beneficial impacts is the adaptive management built into 4R Nutrient Stewardship. To manage adaptively means to evaluate impacts in your decision cycle. The metrics you evaluate need to reflect impacts important to your local farming system. Farther-reaching impacts of crop nutrition include water quality, air quality, carbon footprint, biodiversity, food security, human nutrition, farm livelihoods, and circularity. By better documenting the decision cycle, our current and past practices, and their relation to impacts, the industry has the opportunity to build public trust.

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

It’s been 10 years since the 4R Plant Nutrition manual was published, setting out principles for the stewardship of plant nutrients agreed to by soil fertility scientists and crop nutrition practitioners. Since then, the industry has done a lot to implement the concept, both globally and in North America. What has been learned and accomplished in the process? What needs to be done to take 4R further?

Phosphorus (P) loss pathways should be considered in the context of how management strategies interact with soil and field characteristics. Investigations of P use, soil test P, and P use efficiency have provided some help in navigating through the plight of reducing P losses while maintaining profitable yield levels. The extent to which tillage practices and cover crops are utilized should inform P management strategies and how agronomic, economic, and environmental success are attained.

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

An increasing frequency of environmental stresses on crop yields, concern of air and water quality, and financial pressure all warrant the need for a focus on nutrient use efficiency (NUE). For the values to be meaningful at the farm level, a relationship between management decisions and NUE should be identified. The status and trend of NUE in U.S. cropping systems will be discussed to provide a baseline understanding of where we are with the use of this metric and where measuring NUE is beneficial.

This article is part of a series from The Fertilizer Institute, highlighting some of the latest 4R research. 

Soil health and 4R nutrient stewardship practices work together on farms to reduce nutrient losses. Farmers who work with the Soil Health Partnership (SHP) are adopting both at the same time. In the summer of 2020, SHP asked farmers about nutrient management practices on their SHP research fields between 2014 and 2019. This article focuses on the farmer-reported nutrient management practices from that survey in years where corn was grown on the SHP research field from 105 farms that reported nutrient management practices in at least one corn year.

Decreased atmospheric inputs of sulfur (S) to cropland and increasing removal with harvested crops necessitates a closer look at sulfur fertility management using the 4Rs. Considering the soil organic matter, percent sand, crop status, and sulfur fertilizer solubility are critical to meeting crop nutrition needs for optimal production. 

As companies and farmers seek to show progress towards sustainability goals, they need metrics to assess and document progression. Nitrogen balance—or N-balance—is one frequently used metric to assess the sustainability of nitrogen management.

Precision agriculture plays a large role for crop advisers and farmers when developing 4R nutrient management plans. Combining temporal and spatial yield data can help farmers and consultants manage areas of fields or farms based on their differences from farm average yield and variability to improve nutrient use efficiency. The development of tools that use an increasing number of data layers together—beyond only yield maps—is needed to improve the interpretation and implementation of data-intensive precision agriculture. 

Copper nutrition is critical to the success of a crop, but the complex relationships of copper to soil properties that impact availability need to be understood when making 4R decisions about copper application. 

Though iron deficiency symptoms can be visually apparent in most crops, the underlying reasoning for reduced uptake or availability can be more complex. Dedicating time to understanding the soil-plant environment in each distinctive soil where you suspect iron to be limiting productivity is well worth it. 

While it might not be easy to define soil health, soils with little erosion, higher water stable aggregation, higher organic matter, and incorporated nutrients can function differently than other, less healthy soils. Understanding how the soil functions at a chemical, physical, and biological level is critical to making effective system-level management decisions.