Duration: 10/01/2026 to 09/30/2031

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Soil testing is one of the most important tools farmers use to guide fertilizer decisions. When fertilizer is over-applied, nutrients like nitrogen and phosphorus can be lost to lakes and rivers, harming water quality and increasing costs. When too little fertilizer is applied, crops cannot reach their yield potential, reducing farm income. As soils and climates differ across the North Central region, states use different soil testing methods to best predict how crops will respond to fertilizer. Keeping these methods accurate and up-to-date is essential for profitable and environmentally responsible farming.

The goal of NCERA-13 is to ensure that soil and plant testing methods across the region are scientifically sound, consistent, and clearly communicated to farmers, crop advisors, laboratories, and state and federal agencies. The group’s objectives include sharing information among university and commercial laboratories, updating regional testing guidelines, evaluating new testing methods, and hosting workshops that strengthen understanding and use of soil and plant analysis.

The primary audiences benefiting from this work include farmers, agronomists, public and private soil testing laboratories, Extension professionals, and agencies that rely on university-based recommendations for cost-share and crop insurance programs. These groups benefit through more reliable fertilizer recommendations, greater confidence in laboratory test results, and reduced environmental risk.

Annual meetings, coordinated research, method evaluations, and revised soil testing chapters ensure that the committee’s activities directly support improved fertilizer recommendations. By connecting researchers, laboratories, and educators, NCERA-13 helps deliver trusted, science-based guidance that improves farm profitability while protecting natural resources. The keystones of NCERA-13 activities and products align with USDA Science Priorities focus to support thriving and sustainable farms and ranches across the north central region.

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 online at https://extensiondata.missouri.edu/pub/pdf/specialb/sb1001.pdf

Soil testing is the basis for all P, potassium (K), liming (pH and buffer 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 response to fertilization 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 NCERA-13 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 lab certification programs 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.

The objectives and output of the NCERA-13 committee are specific to the north central region soils, cropping systems, environmental challenges, and stakeholder demographics (farmers, industry, public agencies), that require active and engaged scientists producing local data and insights. Thus, the objective and activities are uniquely designed to address biophysical and agricultural system-specific needs of the region. 

The objectives and activities of the NCERA-13 committee have a long history of and continue to address the following USDA Science Priorities: Increasing Profitability of Farmers and Ranchers and Promoting Soil Health to Regenerate Long-Term Productivity of Land. Economic success of the farmer and long-term sustainability are keystones of NCERA-13 activities, as evidenced by the emphasis on site-specific nutrient management, soil and plant testing to guide economic and probability-based responses to nutrient management, and finally incorporating soil health tests into common method guidelines to ensure farmers’ soil health goals are supported by the best science.

Objectives

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. This includes a regional USDA NRCS award “Enhancing tools to manage phosphorus in agricultural fields in the Northcentral region to reduce the risk loss to surface waters: a project supporting the Fertilizer Recommendation Support Tool (FRST)”, led by NCERA-13 members.

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, NRSP11 and NCERA180 Regional Committees. Continue a working relationship with SERA-IEG-6.

5. Disseminate outputs through workshops, publications, user support tools, and a website.

 

 

Expected Outcomes and Impacts

Projected Participation

View Participation Form/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 2026, 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. To build strong relationship between the NCERA-13 committee and future professionals in soil and plant analysis, the committee will partner with the Agricultural Laboratory Testing Association (ALTA) to connect instructors at Land Grant Universities teaching soil fertility and nutrient analysis courses with the commercial soil testing industry. This will be facilitated through sponsored lectures on campus, and targeted recruitment of students to the biennial workshops.

It is important to extend our knowledge beyond the North Central Region. A regional workshop will be scheduled for 2028 hosted by the NECC1012 including the NCERA-13 and SERA06 committees.

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 2026 will be held during the 2026 North Central Extension-Industry Soil Fertility Conference in Des Moines, IA. Subsequent meetings will be held, in alternating years, in the fall (2026, 2028) and workshops in the spring (2027, 2029). Additionally, a virtual meeting will be held in 2026 to facilitate methods chapter updates and editorial activities.

Organization/Governance

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: 

Jones, J. D., Miller, R. O., Spargo, J. T., Sikora, F. J., Rakkar, M. K., Slaton, N. A., & Osmond, D. L. (2025). Assessment of soil pH and lime requirement methods and recommended lime rates for six reference soils across US land grant institutions. Soil Science Society of America Journal, 89, e70116. https://doi.org/10.1002/saj2.70116

Recommended chemical soil test procedures. 2015. Missouri Agricultural Experiment Station Bulletin SB 1001. Revised. https://extensiondata.missouri.edu/pub/pdf/specialb/sb1001.pdf

Franzen, D.W. & NCERA-13 committee. Limitations of the sulfate-sulfur soil test as a predictor of sulfur response. 2018. NDSU Extension Circular SF1880. http://ncera-13.missouri.edu/pdf/Limitations_of_Sulfate_2018.pdf

Fertilizer Guidelines for Agronomic Crops in Minnesota

https://extension.umn.edu/nutrient-management/crop-specific-needs

University of Minnesota recommendations and use of soil testing- https://extension.umn.edu/nutrient-management/testing-and-analysis 

University of Minnesota recommendations for plant analysis - https://extension.umn.edu/testing-and-analysis/understanding-plant-analysis-crops 

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

https://soilweb.spnl.msu.edu/fmi/webd?homeurl=https://www.canr.msu.edu/fertrec/#WebClient 

Culman et al. Michigan/Ohio/Indiana Tri-State Fertilizer Recommendations. 2020.    https://agcrops.osu.edu/FertilityResources/tri-state_info 

Fernandez F. and R.G. Hoeft. Managing soil pH and crop nutrients. Chapter 8 in Illinois Agronomy Handbook. http://extension.cropsciences.illinois.edu/handbook/pdfs/chapter08.pdf 

Soil test interpretations and recommendations handbook. University of Missouri, revised 2004. http://aes.missouri.edu/pfcs/soiltest.pdf 

A General Guide for Crop Nutrient and Limestone Recommendations in Iowa. Rev. 2023. https://shop.iastate.edu/extension/farm-environment/crops-and-soils/soil-fertility-and-management/pm1688.htmlShaver, T. Nutrient management for agronomic crops in Nebraska. https://extensionpublications.unl.edu/assets/pdf/ec155.pdf 

Clark, J. Fertilizer Recommendation Guide for South Dakota. Rev. 2020. https://extension.sdstate.edu/fertilizer-recommendation-guide 

Kansas State University fertilizer recommendations. https://www.agronomy.k-state.edu/services/soiltesting/fertilizer-recommendations/index.html 

North Dakota Fertilizer Recommendation Tables and Equations. SF882 Rev. 2020. https://www.ndsu.edu/fileadmin/soils.del/pdfs/North_Dakota_Fertilizer_Recommendation_Tables_and_Equations_SF882.pdf 

North Dakota corn N calculator https://www.ndsu.edu/pubweb/soils/corn/

North Dakota spring wheat & durum N calculator https://www.ndsu.edu/pubweb/soils/wheat/

North Dakota sunflower N calculator https://www.ndsu.edu/pubweb/soils/sunflower/

North Dakota corn K calculator https://www.ndsu.edu/pubweb/soils/corn_k/

Nutrient management in Wisconsin https://ipcm.wisc.edu/downloads/nutrient-managment/ 

Laboski and Peters. Nutrient application guidelines for field, vegetable, and fruit crops in Wisconsin. https://cdn.shopify.com/s/files/1/0145/8808/4272/files/A2809.pdf

Attachments

Land Grant Participating States/Institutions

IA, IL, IN, KS, MN, MO, ND, NE, OH, SD, WI

Non Land Grant Participating States/Institutions