NCERA13: Soil Testing and Plant Analysis

(Multistate Research Coordinating Committee and Information Exchange Group)

Status: Active

NCERA13: Soil Testing and Plant Analysis

Duration: 10/01/2021 to 09/30/2026

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

A foundational component for most crop nutrient fertilizer applications, whether with chemical fertilizers or with organic-approved sources, is soil testing and plant analysis. Proper fertilizer rates are necessary for economically and environmentally sound fertilizer and amendment application. Excessive fertilizer rates of nitrogen (N) and phosphorus (P) may result in ground/surface water contamination, increasing the risk for surface water eutrophication (N and P), and even human/animal health (N). Insufficient crop nutrient application results in decreased farmer profitability.

Soil testing has been a cornerstone for profitable crop production for over 100 years, and methods have continually been refined and updated, along with state recommendations that vary not so much because of state boundary lines, but due to the soil and climate variances present within each state. Current methods for soil testing are published in North Central Regional Research Publication No. 221 (Revised), Missouri Agriculture Experiment Station Bulletin SB 1001, housed on line at

Soil testing is the basis for all P, potassium (K), liming (pH), and micronutrient recommendations in the North Central Region. In the drier/colder states in the region, which include North Dakota, South Dakota and western/northern Minnesota, residual soil nitrate is an important component of all soil testing for N requiring crops and even soybean in North Dakota, due to its interaction with iron deficiency chlorosis. Parts of the region include soil testing for zinc (Zn), while in other states (IN, MI, OH) manganese (Mn) is an important consideration.

              Methods used for soil testing differ between states. The reason  behind the different methods is the relationship of test values to crop yield and sometimes crop quality within each state. For example, some states utilize the Mehlich 3 extraction for P, while other states have found that the Mehlich 3 relationship to crop response is reduced when soil carbonates (high pH) are present. Therefore, states with significant areas with carbonates utilize the Olsen extractant. Other states have found that the Bray-1 is still the most predictive extractant for crop response to P in their soils. The NCERA13 methods publication details all methods that are used by the states, and then leaves it to each individual state to use the method that best predicts the probability of profitable and environmentally responsible response. Each state has people associated and in communication with the NCERA-13 representative that continually correlate and calibrate soil testing methods with crop response. In several states, the people conducting this research in the NCERA-13 representative. The NCERA-13 committee is a structured way for communication of these continuing research studies to representatives from the other participating states, and promotes discussion of methods and their use as well as spurring innovation and improvement in new or existing methods.

Seventy years ago, when the NCERA-13 committee was formed within USDA, most of the participating states operated a ‘state laboratory’, housed by the Land Grant institution in each state. Illinois was the only state that never had a state laboratory, but the Illinois representative worked with an association of privately owned laboratories to ensure they used the best methods for soil analysis. Today, North Dakota, Wisconsin, Kansas and Michigan still operate state laboratories; however, even in these states most soil analysis is conducted by private laboratories. The NCERA-13 committee and its members maintain a connection with private laboratories and work with them to encourage them to use the best soil testing methods most related to crop responses to fertilizer nutrients and amendments. In addition to the importance of soil testing methods, the USDA-NRCS requires recipients of federal nutrient management programs to utilize University recommendations, which are based largely on soil testing and the calibration work that members of the NCERA-13 committee and their associates have conducted. Also, federal crop insurance requires farmers to utilize University recommendations to qualify for disaster assistance. These recommendations are the product of the NCERA-13 committee work.



  1. Nurture a formalized structure for information exchange between university and commercial soil test laboratory personnel throughout the region.
  2. Continue to provide a website to improve the marketing of the products and activities generated by this committee.
  3. Organize every other year a soil testing and plant analysis conference/workshop targeted to member public laboratories and NCERA13 committee members to foster the use and understanding of improved soil/tissue testing methods and interpretations in the North-Central region.
  4. Update specific chapters of the book “Recommended Chemical Soil Test Procedures for the North Central Region” as the need arises.
  5. Investigate new soil testing methods and compare calibration and correlation of new method values with existing recommended methods.Investigate new soil testing methods and compare calibration and correlation of new method values with existing recommended methods.

Procedures and Activities

The committee is composed of North Central Region land grant university representatives with expertise in laboratory operations, soil testing and plant analysis, and field-based soil and plant tissue test calibration and correlation studies to develop nutrient recommendations. This committee will:

1. Meet annually to discuss: 1) the principles underlying various soil and plant tissue tests, 2) results of research on new analytical methods, innovations in laboratory operations and instrumentation, 3) the use of information technology and computer programming for lime and nutrient recommendations, 4) the role of soil and plant tissue testing in nutrient management plan development and implementation and 5) soil test result summaries by state and geographic regions.

2. Collaborate in research studies and literature reviews on various aspects of soil fertility diagnosis and correction including laboratory quality control and quality assurance, soil and plant tissue test correlations with crop responses to nutrient applications.

3. Foster the initiation of additional research where needed to improve soil testing, plant analyses and nutrient application recommendations by bringing these needs to the attention of the appropriate persons or agencies.

4. Maintain representation and provide advice to the North American Proficiency Testing (NAPT) program and state entities involved in laboratory oversight, and improve communications with the NC218, SERA006, SERA017 and NCERA180 Regional Committees. Continue a working relationship with SERA-IEG-6.

5. Disseminate outputs through, workshops, publications, and a website.

Expected Outcomes and Impacts

  • Revise chapters in NCERA Res. Publ. No. 221, “Recommended chemical soil test procedures” as needed. There are no chapter revisions anticipated in 2021.
  • Increase the agricultural community’s awareness of the importance of utilizing properly correlated and calibrated soil and plant analysis methods.
  • Improve collaboration between public and private laboratories by working together on current analytical challenges and stressing the importance of using methods that are highly related to crop response.
  • Committee members make recommendations on interpretation of soil and tissue analysis. These recommendations have significant positive economic impact for producers in the North Central Region and their use serves to limit adverse environmental consequences from wasteful and excessive nutrient applications.

Projected Participation

View Appendix E: Participation

Educational Plan

Outreach and educational activities will be targeted towards increasing the knowledge of private laboratory staff, producers, the broader agricultural community and the general public regarding soil and plant analysis and interpretations. This will be done by preparing and publishing Extension bulletins, updating web resources, organizing regional laboratory workshops in 2022, and otherwise serving as a source of information on soil and plant analyses, and the interpretation of analyses and nutrient application recommendations. 

Undergraduate students (hired) and graduate students (through research programs) of the members of the NCERA-13 committee engage with the soil and plant analysis laboratories in each state. Students in a University that supports a state laboratory would gain experience with the methods used in the state. In states without an official state laboratory, the committee members still have a laboratory that they supervise or work with a colleague who has a laboratory that uses the North Central methods where students gain experience.

It is important to extend our knowledge beyond the North Central Region. This June, 2021, there will be a virtual workshop between NCERA-13, SERA 006 and NC1195, organized by SERA006, with assistance of members of the NCERA-13 committee.

The North Central Region has a large number of commercial soil testing laboratories that utilize methodologies that have been previously proposed, evaluated and adopted as standard methods for soil analysis by this committee. We will continue our formal interactions with commercial soil testing laboratories during this project period. Our public/private lab workshop scheduled for 2021  will be delayed due to our joint meeting with SERA006 and NC1195, but we will reschedule our private/public workshop in 2022.


The recommended Standard Governance for multistate research activities include the election of a Chair, a Chair-elect, and a Secretary. All officers are to be elected for at least two-year terms to provide continuity. Administrative guidance will be provided by an assigned Administrative Advisor and a NIFA Representative.

Literature Cited

Literature that directly utilizes NCERA13 soil testing/plant analysis methods in the North Central Region within individual states or multi-state regions: 

Recommended chemical soil test procedures. 2015. Missouri Agricultural Experiment Station Bulletin SB 1001. Revised.

Franzen, D.W. & NCERA-13 committee. Limitations of the sulfate-sulfur soil test as a predictor of sulfur response. 2018. NDSU Extension Circular SF1880.

University of Minnesota recommendations and use of soil testing- 

University of Minnesota recommendations for plant analysis - 

Michigan State Fertilizer Recommendation Program, requiring soil test value input - 

Culman et al. Michigan/Ohio/Indiana Tri-State Fertilizer Recommendations. 2020. 

Fernandez F. and R.G. Hoeft. Managing soil pH and crop nutrients. Chapter 8 in Illinois Agronomy Handbook. 

Soil test interpretations and recommendations handbook. University of Missouri, revised 2004. 

A General Guide for Crop Nutrient and Limestone Recommendations in Iowa. Rev. 2013. file:///C:/Users/david.franzen/Downloads/PM1688%20(4).pdf

Shaver, T. Nutrient management for agronomic crops in Nebraska. 

Clark, J. Fertilizer Recommendation Guide for South Dakota. Rev. 2020. 

Kansas State University fertilizer recommendations. 

North Dakota Fertilizer Recommendation Tables and Equations. SF882 Rev. 2020. 

North Dakota corn N calculator

North Dakota spring wheat & durum N calculator

North Dakota sunflower N calculator

North Dakota corn K calculator

Nutrient management in Wisconsin 

Laboski and Peters. Nutrient application guidelines for field, vegetable, and fruit crops in Wisconsin.



Land Grant Participating States/Institutions


Non Land Grant Participating States/Institutions

Wisconsin State Laboratory of Hygiene (WSLH)
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