What are the 4Rs

4R Principles

The 4R nutrient stewardship principles are the same globally, but how they are used locally varies depending on field and site specific characteristics such as soil, cropping system, management techniques and climate. The scientific principles of the 4R framework include:

Right Source – Ensure a balanced supply of essential nutrients, considering both naturally available sources and the characteristics of specific products, in plant available forms.

Right Rate – Assess and make decisions based on soil nutrient supply and plant demand.

Right Time – Assess and make decisions based on the dynamics of crop uptake, soil supply, nutrient loss risks, and field operation logistics.

Right Place – Address root-soil dynamics and nutrient movement, and manage spatial variability within the field to meet site-specific crop needs and limit potential losses from the field.

4R nutrient stewardship provides a framework to achieve cropping system goals, such as increased production, increased farmer profitability, enhanced environmental protection and improved sustainability.

To achieve those goals, the 4R concept incorporates the:

• Right fertilizer source at the
• Right rate, at the
• Right time and in the
• Right place

Properly managed fertilizers support cropping systems that provide economic, social and environmental benefits. On the other hand, poorly managed nutrient applications can decrease profitability and increase nutrient losses, potentially degrading water and air.
4R nutrient stewardship requires the implementation of best management practices (BMPs) that optimize the efficiency of fertilizer use. The goal of fertilizer BMPs is to match nutrient supply with crop requirements and to minimize nutrient losses from fields. Selection of BMPs varies by location, and those chosen for a given farm are dependent on local soil and climatic conditions, crop, management conditions and other site specific factors.
Other agronomic and conservation practices, such as no-till farming and the use of cover crops, play a valuable role in supporting 4R nutrient stewardship. As a result, fertilizer BMPs are most effective when applied with other agronomic and conservation practices.

Benefits of Using the 4Rs

Agriculture Must Respond To The Pressures of Increasing Population and Regulation

4R nutrient stewardship can help IMPROVE AGRICULTURAL PRODUCTIVITY:

• Optimizing nutrient management is simply good business in dealing with fluctuations in prices of fertilizers and other inputs, as well as in process of crops sold.
• Higher crop yields are well documented with better crop and soil management.
• Improved fertilizer efficiency increases the quantity produced per acre for each unit of nutrient applied, without sacrificing yield potential.

4R nutrient stewardship can help MINIMIZE IMPACT TO THE ENVIRONMENT:

• Adopting nutrient stewardship contributes to the preservation of natural ecosystems by growing more on less land.
• Retaining nutrients within a field’s boundaries and in the crop rooting zone greatly reduces the amount that is not utilized by plants and thereby escapes into the environment as pollution.

Sustainability

4R nutrient stewardship promotes the achievement of social, economic and environmental goals.
Some commonly identified grower objectives that promote the sustainable nature of 4R nutrient stewardship include the following:

Economic Goals

• Improve net farm income.
• Contribute to improved regional economic development.

Social Goals

• Improve the quality of farm family housing, diet and education.
• Improve productivity of farm labor by appropriate use of emerging technologies that increase efficiencies of field operations and reduce costs per unit of crop harvested.
• Improve access to sources of information to assist in farm management decision making.

Environmental Goals

• Maintain or reduce unwanted losses of nutrients to the environment:
  • Reduce soil erosion of nutrient containing soil particles;
  • Reduce volatile ammonia (NH₃) emissions;
  • Reduce nitrification / de-nitrification losses of nitrous oxide (N₂O) and di-nitrogen (N₂).
• Reduce energy use per harvested unit of farm production.
• Improve recycling of crop nutrients from crop residues and livestock manures.
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