NCERA_temp13: Soil Testing and Plant Analysis
(Multistate Research Coordinating Committee and Information Exchange Group)
Status: Under Review
NCERA_temp13: Soil Testing and Plant Analysis
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.
Statement of Issues and Justification
Soil testing is an important tool to help farmers manage crop nutrients. Soil testing uses specific chemical extractants to predict the availability of important crop nutrients to plants and require correlation and calibration to be useful. Regional research has been critical to help determine which tests best work for soils to predict crop response. Soil testing laboratories have many options for what chemical extractants to use but research on methods and the development of standards are critical to ensure repeatability of tests as well as ensure that the data growers use is valid and can be compared to land grant university fertilizer guidelines. Changes in methodologies used for soil chemical extractions can have a significant impact on results and coordination across states in the region is critical. Consistent messaging on the importance and use of soil testing within the North Central region is beneficial with farms becoming larger and crossing borders. The collaboration of states represented by this committee is key to maintain trust in the use of soil testing for the management of commercial fertilizers, soil amendments, livestock manure, and biosolids.
Impairment of surface waters from runoff of excess crop nutrients such as nitrogen (N) and phosphorus (P) are of serious concern. Many states in the North Central region have been working on nutrient reduction strategies to achieve reductions in nutrient loss to surface waters. Soil testing is a key component for some nutrients to identify points where crops no longer need nutrients applied as well as points as which nutrient loss is a concern. In addition, soil testing is an important part of conservation practices outlined in the NRCS (Natural Resources Conservation Service) conservation practices standards.
The NCERA13 committee has long worked with soil testing laboratories in the region providing up-to-date methods for the determination of nutrient concentrations in soils and plants. Members also have, through their university appointments, provided data linking soil test data to crop response and the amount of fertilizer required to optimal crop yields. Key stakeholders that use this information are agriculture businesses such as fertilizer retailers, crop consultants, and soil testing laboratories and ultimately farmers who rely on up-to-date information that provides economical and environmentally sound soil test-based fertilizer recommendations.
The NCERA13 committee provides critical information to guide how plant analysis can be used appropriately to make fertilization decisions. Plant analysis is commonly used to diagnose crop nutrient deficiencies and quantify nutrient uptake and removal of crop nutrients for forage and grain crops. Effective use of plant tissue analysis for nutrient management decisions relies on appropriately calibrated tissue analysis with the potential for yield response to fertilization, and reproducible laboratory methods of analysis.
Objectives
-
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. 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 NCERA13 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, and a website.
Expected Outcomes and Impacts
- Update NCERA RE. Publication No. 221 “Recommended chemical soil test procedures” Comments: Revise chapters in NCERA Res. Publ. No. 221, “Recommended chemical soil test procedures” as needed. The following chapters are planned for revisions in 2026, with additional chapters if needed following review: 1. Chapter 6: Phosphorus (previously revised January 1998) 2. Chapter 7 Potassium and Other Basic Cations (previously revised January 1998)
- Integrate activities from 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)”, in which the Lead-PI and co-PIs are NCERA13 members, to communicate three region-wide issues. Comments: Integrate activities from 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)”, in which the Lead-PI and co-PIs are NCERA13 members, to communicate three region-wide issues: 1. Comparisons of soil-test phosphorus methods (Bray-1, Mehlich-3 colorimetric, Mehlich-3 ICP, and Olsen) for field calibration with crop response to fertilization 2. Regional variation and variability of crop nutrient removal with harvest through creation of a region-specific database for the North Central Region. 3. Increase the number of trials on correlation of soil tests for inclusion in databases for current regional projects or future use for models or artificial intelligence analysis of crop response data.
- Publish a North Central Region NCERA13 report to summarize soil health testing for phosphorus and potassium, aggregating work from multiple states where the majority of correlation between soil health tests and response to fertilization has been done.
- 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. Comments: 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: ParticipationEducational 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.
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 NCERA013 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.
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