Understanding CSR2 and Your Soil Quality: Guide for Iowa Farmers

Soil health is crucial for sustainable agriculture. Healthy soil supports plant growth, enhances water and nutrient retention, and promotes biodiversity. Understanding and improving soil health can lead to better crop yields and more resilient farming systems.

What Is the Corn Suitability Rating (CSR2) Index?

The Corn Suitability Rating (CSR) is a soil productivity index developed in the 1970s to assess the potential productivity of soils for corn production in Iowa. The CSR2 is an updated version of the original CSR, introduced in 2013, to provide greater transparency and consistency in soil productivity evaluation.

CSR2 is used to:

• Evaluate soil quality and productivity.
• Assist in farmland appraisals and rental agreements.
• Inform management decisions to optimize crop production.

The CSR2 index considers various soil properties and field conditions to provide a relative rating of soil productivity. 

How Are CSR2 Scores Calculated?

The CSR2 score is calculated using an equation that incorporates several factors:

• Soil Properties: These include soil type (sand, clay, silt, loam), texture, organic matter, biological activity, pH levels and water retention.
• Field Condition: Characteristics such as slope, flooding, erosion, top-soil thickness and compaction are considered.
• Soil Depth: The depth of the soil affects its resistance to erosion, water absorption and biodiversity

The CSR2 equation is: CSR2 = S – M – W – F – D ± EJ 

Where:

• S is the taxonomic subgroup class of the soil map unit.
• M is the family particle size class.
• W relates to available water holding capacity.
• F is the field condition.
• D is the soil depth and tolerable rate of soil erosion.
• EJ is an expert judgment correction factor.

What Is a Good CSR2 Rating?

CSR2 ratings range from 5 to 100, with higher numbers indicating more productive soils. Here are the benchmarks for CSR2 ratings in Iowa: 

• High: CSR2 > 83 (Very productive soils)
• Medium: CSR2 65-82 (Productive soils with some limitations)
• Low: CSR2 < 65 (Less productive soils)

The average CSR2 rating for farmland across Iowa varies, but understanding your specific rating can help you make informed decisions about land management.

How to Evaluate the Corn Suitability Rating of Your Farm

Farmers can evaluate the CSR2 score of their acreage using resources like the USDA Web Soil Survey website. This tool provides detailed soil maps and allows you to calculate the CSR2 for different parts of your land. Keep in mind that CSR2 scores can vary within a single farm due to differences in soil properties and field conditions.

Can CSR2 Be Increased?

While CSR2 scores are fixed based on inherent soil properties, there are ways to improve overall soil quality and crop yield potential, such as soil testing. Here are some additional practices to consider:

• Crop Rotation: Diversifying crops can improve soil structure and fertility.
• Nutrient Management: Proper fertilization ensures that plants receive the necessary nutrients.
• Irrigation and Drainage Upgrades: Efficient water management can enhance soil health and productivity.

How CSR2 Impacts Land Value and Property Taxes

CSR2 ratings can play a significant role in farmland appraisals. Higher CSR2 scores generally correlate with higher land values and sale prices. Additionally, county-level CSR2 averages are used to determine property tax rates for agricultural land. Understanding your CSR2 rating can help you make informed decisions about buying, selling, or managing farmland.

Know the Soil You’re Working With

When it comes to the profitability of your operation, understanding your soil health is critical. While you can take steps to improve your soil health, the unexpected can happen. Having a local Farm Bureau Financial Services team provide you with the coverage you need to prepare for the next season can help. From property and liability insurance to crop and machinery coverage, our personalized approach will meet the needs of your operation.