Soil Fertility Iowa State University

This theme uses "root" links to dependencies and assets (CSS, JS, images, etc.). Place all theme files and directories at the root of your web server for this page to render as intended.

Soil/Plant Sampling, Testing, and Recommendations

Extension Publications

Presentations

Soil sampling and testing, basic concepts, use, and interpretation. A.P. Mallarino. 2020. Soil fertility and nutrient management short course. Iowa State University Extension and Outreach, Ames.

Newsletter Articles

Fall Phosphorus and Potassium Fertilization Decisions with Variable Prices (9/2023)
Plant Tissue Testing may be Useful this Season but be Aware of Potential Drought Effects (6/2023)
Phosphorus and Potassium Soil-Test Interpretation Guidelines Have Changed (2/2023)
Beware of Dry Conditions When Soil Sampling and Interpreting Test Results (10/2022)
Soil-test interpretations for fall fertilization and liming decisions with high fertilizer prices and after highly variable rainfall and crop yields (10/2021)
Thinking of plant tissue testing this season? Beware of drought or excess moisture effects (7/2021)
Be cautious when interpreting fall soil-test results following drought (10/2020)
Nutrient removal when harvesting corn stover (9/2019)
Flood adulterated grain - nutrient supply to crops when land applied (4/2019)
Tissue testing for field crops requires cautious use and interpretation (6/2019)
Estimating losses when cornstalk fields are accidentally burnt -- Revised July 20, 2017
Dry fall conditions can lead to field fires -- Revised July 20, 2017

Conference Proceedings and Reports

Mallarino, A.P. 2023. Iowa P and K soil-test interpretations were updated in 2023: Changes and Reasons. Proceedings, 53rd North Central Soil Fertility Conf., Nov. 1516, 2023.
Mallarino, A.P., 2018. Corn and soybean grain yield, phosphorus and potassium removal, and soil-test trend responses to long-term fertilization strategies. p. 83-90. In 30th Integrated Crop Management Conf. Proceedings. Nov. 28-29, 2018. Iowa State Univ. Extension.
Mallarino, A.P., and J.D. Jones. 2018. Correlation of the weak organic acids test of a soil health tool with crop yield response to phosphorus fertilization. p. 14-20. In 48th North-Central Extension-Industry Soil Fertility Conf. Proceedings. 14-15 Nov. 2018. Vol. 34. Des Moines, IA. International Plant Nutrition Institute, Peachtree Corners, GA.

View conference proceedings and reports 2016 and earlier -- click here to expand

Mallarino, A.P. 2016. Value of tissue testing to improve phosphorus, potassium, and micronutrients management for corn and soybean. p. 139-146. In The Integrated Crop Management Conf. Proceedings. Nov. 30-Dec. 1, 2016. Iowa State Univ. Extension.
Mallarino, A.P. 2016. What can long term experiments provide for improving phosphorus and potassium management? p. 12-16. In 65th North-Central Extension-Industry Soil Fertility Conf. Proceedings. Nov. 2-3 2016. Vol. 32. Des Moines, IA. International Plant Nutrition Institute, Brookings, SD.
Mallarino, A.P., and R.R. Oltmans. 2014. Potassium management, soil testing and crop response. p. 45-52. In 44th North-Central Extension-Industry Soil Fertility Conf. Proceedings. Nov. 19-20 2014. Vol. 30. Des Moines, IA. International Plant Nutrition Institute, Brookings, SD.
Mallarino, A.P., and J.E. Sawyer. 2013. Update to Iowa phosphorus, potassium, and lime recommendations. p. 137-143. In The Integrated Crop Management Conf. Proceedings. Dec. 4-5, 2013. Iowa State Univ. Extension.
Mallarino, A.P. 2013. Re-implementation of moist soil testing to improve the assessment of crop-available potassium in Iowa soils. In Proceedings, NCERA-13 Committee (eds.) North Central Region Soil and Plant Analyst Workshop. Feb. 26-27, 2013. Iowa City, IA.
Mallarino, A.P. 2012. Nutrient management for increased crop productivity and reduced environmental impacts. Proc. Joint XIX Latin American and XXIII Argentinean Soil Science Congress. 16-20 April, 2012. Mar del Plata, Argentina.
Mallarino, A.P. 2012. Testing field-moist soil samples improves the assessment of potassium needs by crops. p. 137-144. In The Integrated Crop Management Conf. Proceedings. Nov. 28-29, 2012. Iowa State Univ. Extension.
Mallarino, A.P., B.E. Hill, and K.L. Culp. 2011. Iowa soil test summaries 2006-2010. Iowa State Univ., Dep. of Agronomy, Ames, IA
Mallarino, A.P., M.W. Clover, and R.R. Oltmans. 2011. Identification of Reasons for High Temporal Soil-Test Potassium Variation. p. 65-73. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Vol. 27. Des Moines, IA
Mallarino, A.P, and T.S. Murrell. 2004. Detecting phosphorus with plasma emission spectroscopy may require unique field calibration data. Better Crops Plant Food 88(2):12-15.
Mallarino, A.P., D.J. Wittry, and P.A. Barbagelata. 2002. Iowa soil-test field calibration research update: Potassium and the Mehlich-3 ICP phosphorus test. p. 29-39. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Vol. 17. Des Moines, IA.
Mallarino, A.P., and D. Wittry. 2001. Management zones soil sampling: A better alternative to grid and soil type sampling? p. 159-164. In The Integrated Crop Management Conf. Proceedings. Dec. 5-6, 2001, Ames, IA. Iowa State Univ. Extension.
Mallarino, A.P., and D. Wittry. 2000. How can we make intensive soil sampling and variable-rate P and K fertilization cost-effective? p. 203-210. In The Integrated Crop Management Conf. Proceedings. Nov. 29-30, 2000. Ames, IA. Iowa State Univ. Extension.
Mallarino, A.P., and D.J. Wittry. 2000. Identifying cost-effective soil sampling schemes for variable-rate fertilization and liming. In P.C. Robert et al. (ed.). Fifth Intl. Conf. on Site-Specific Management for Agricultural Systems. Proceedings. CD-ROM. July16-19. Bloomington, MN. ASA, CSSA, SSSA, Madison, WI.
Mallarino, A.P. 1999. Soil phosphorus testing for crop production and environmental purposes. p 185-192. In The Integrated Crop Management Conference. Proceedings. Dec. 1-2, 1999. Iowa State Univ. Extension. Ames.
Sawyer, J.E. 1999. Making every fertilizer dollar pay. p. 63-78. In Proc. Integrated Crop Manag. Conf., Ames, IA. 1-2 Dec. Iowa State Univ., Ames, IA.
Sawyer, J.E., and A.P. Mallarino. 1999. Differentiating and understanding the Mehlich 3, Bray, and Olsen soil phosphorus tests. Presented at the 19th Annual Crop Pest Management Short Course, Univ. of Minnesota, Nov. 22, 1999. St. Paul, MN.
Mallarino, A.P., and D. Wittry. 1999. Challenges for making intensive soil sampling and variable-rate technology pay. p.104-109. In North Central Extension-Industry Soil Fertility Conference. Proceedings. Vol. 15. St. Louis, MO.
Sawyer, J.E. 1998. Managing crop nutrients and limestone with reduced financial resources. p. 33-36. In Proc. Integrated Crop Manag. Conf., Ames, IA. 17-18 Nov. Iowa State Univ., Ames, IA.
Mallarino, A.P. 1995. Comparison of Mehlich-3, Olsen, and Bray-P1 procedures for phosphorus in calcareous soils. p. 96-101. In G. Rehm (ed.) North Central extension-industry soil fertility conference. Proceedings. Vol. 11. St. Louis, MO.

Featured

Take a Good Soil Sample to Help Make Good Fertilization Decisions
Antonio Mallarino, John Sawyer

Learn more about the most important step in soil testing to make fertilization decisions for FIELD CROPS - collecting the soil sample. Includes information on materials needed, when to sample, how to select a sample area, how often to sample and much more.

Quick Links

Corn Nitrogen Rate Calculator

ISU Extension and Outreach Store

ISU Integrated Crop Management

ISU Integrated Crop Management Blog

North Central Extension-Industry Soil Fertility Conference