Phosphorus

Extension Publications

• Agricultural Phosphorus Management and Water Quality Protection in the Midwest
• CROP 3153 Phosphorus and Potassium Tissue Testing in Corn and Soybean
• PM 869 Fertilizing Pastures
• PM 1688 A General Guide for Crop Nutrient and Limestone Recommendations in Iowa
• PM 1993 Ten Questions about the Phosphorus (P) Index in Iowa
• PM 3052c Nutrient Considerations with Corn Stover Harvest
• SP 0435A Reducing Nutrient Loss: Science Shows What Works

Presentations

• Soil phosphorus and potassium dynamics and management. A.P. Mallarino. 2020. Soil fertility and nutrient management short course. Iowa State University Extension and Outreach, Ames.
• Site-specific soil fertility management, with emphasis on P, K, and lime. A.P. Mallarino. 2020. Soil fertility and nutrient management short course. Iowa State University Extension and Outreach, Ames.

Newsletter Articles

• 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)
• Cold Spring and High Fertilizer Prices may Make Starter Fertilizer More Important (4/2022)
• Wind damaged corn - nutrient content? (8/2020)
• Phosphorus and potassium management for 2020 after a year with highly variable yields (10/2019)
• You couldn’t apply phosphorus and potassium last fall and now it’s too wet (4/2018)
• Fertilization can help with cool soils and late planting dates (4/2018)
• Phosphorus and potassium in silage harvest of drought-damaged corn (7/2017)

View newsletter articles 2015 and earlier -- click here to expand

• Value of soybean tissue testing for phosphorus and potassium (6/2016)
• Research shows a role for phosphorus and potassium tissue testing in corn (6/2016)
• Make rational decisions about phosphorus and potassium management with unfavorable crop prices (9/2015)
• Starter fertilization sometimes boosts corn yield (03/2015)
• Don't underestimate the value of starter fertilizer for corn planted late (5/2013)
• Phosphorus, potassium, and pH management issues following drought-damaged crops (8/2012)
• Phosphorus and potassium in silage harvest of drought-damaged corn (7/2012)

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., L.B. Thompson, J. Sievers, and T. Tuttle. 2020. Long-term phosphorus and potassium placement methods and application rates for corn and soybean managed with no-tillage and tillage. Iowa State Univ. Research and Demonstration Farms Progress Reports 2019. RFR-A1968.
• Mallarino, A.P., 2019. Phosphorus and potassium fertilizer placement options when crop prices are low. p. 123-130. In 31th Integrated Crop Management Conf. Proceedings. Dec. 4-5. 29-30, 2019. Iowa State Univ. Extension.
• Mallarino, A.P., 2019. Efficacy of variable-rate application technology for phosphorus, potassium, and lime management. In 49th North-Central Extension-Industry Soil Fertility Conf. Proceedings. Nov. 5-6. Des Moines, IA.
• 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.
• Mallarino, A.P., and K. Pecinovsky. 2017. Phosphorus and potassium placement for corn and soybean managed with tillage or no-tillage. Farm Progress Reports: Vol. 2016: Iss. 1, Article 76.

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 M.U. Haq. 2016. How can fertilizer and manure management practices reduce dissolved phosphorus loss from fields and improve water quality? p. 179-184. In The Integrated Crop Management Conf. Proceedings. Nov. 30-Dec. 1, 2016. Iowa State Univ. Extension.
• Mallarino, A.P., B. Havlovic, and D. Schaben. 2016. Effects of phosphorus and potassium placement on yield of corn and soybean managed with tillage or no tillage. Armstrong and Neely-Kinyon Research and Demonstration Farms Annual Reports. ISRF15-12, RFR-A1594. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and J. Sievers. 2016. Phosphorus and potassium placement and application rates for corn and soybean managed with no-till or tillage. Northwest Research Farm and Allee Demonstration Farm Annual Reports. ISRF15-29,31, RFR-A1563. Iowa State Univ., Ames, IA.
• Mallarino, A.P. 2015. Making rational adjustments to phosphorus, potassium, and lime application rates when crop prices are low and producers want to cut inputs. p. 149-155. In The Integrated Crop Management Conf. Proceedings. Dec. 2-3, 2015. Iowa State Univ. Extension.
• Mallarino, A.P., and M.U. Haq. 2015. Phosphorus loss with runoff after applying fertilizer or manure as affected by the timing of rainfall. p. 94-99. In 45th North-Central Extension-Industry Soil Fertility Conf. Proceedings. Nov. 19-20 2014. Vol. 31. Des Moines, IA. International Plant Nutrition Institute, Brookings, SD.
• Mallarino, A.P., P. Barbieri, and K. Pecinovsky. 2015. Long-term phosphorus and potassium fertilization effects on yields of corn and soybean grown in rotation. Northeast Research and Demonstration Farm Annual Reports. ISRF14-13, RFR-A14104. Iowa State Univ., Ames, IA.
• Mallarino, A.P. 2014. Making rational adjustments to phosphorus, potassium, and lime application rates when crop prices are low and  producers want to cut inputs. p. 137-143. In The Integrated Crop Management Conf. Proceedings. Dec. 3-4, 2014. Iowa State Univ. Extension.
• Mallarino, A.P. 2013. Interpretation of plant tissue test results for phosphorus and potassium in corn and soybean. In Proc. 2013 North-Central Region Soil and Plant Analysis and NCERA-13 Workshop, Feb. 26-27, Iowa City, IA.
• Mallarino, A.P., and D. Rueber. 2013. Alfalfa hay and soil-test phosphorus responses to long-term phosphorus fertilization strategies. Northern Research and Demonstration Farm Annual Reports. ISRF12-22. Iowa State Univ., Ames, IA.
• Thompson, L.B., A.P. Mallarino, and K.T. Pecinovsky. 2013. Crop response to phosphorus fertilizer or phosphorus recovered as struvite from corn fiber processing for bioenergy. Northeast Research and Demonstration Farm Annual Reports. ISRF12-13. Iowa State Univ., Ames, IA.
• Sawyer, J.E., and A.P. Mallarino. 2012. Nutrient considerations with corn silage and stover harvest. p. 131-136. In The Integrated Crop Management Conf. Proceedings. Nov. 28-29, 2012. Iowa State Univ. Extension.
• Mallarino, A.P., R.R. Oltmans, J.R. Prater, C.X. Villavicencio, and L.B. Thompson. 2011. Nutrient Uptake by Corn and Soybean, Removal, and Recycling with Crop Residue. p. 103-113. In Proc. 23rd Annual Integrated Crop Management Conf., Ames, IA 30 Nov. – 1 Dec. 2011. Iowa State Univ., Ames, IA
• Oltmans, R.R., and A.P. 2011. Phosphorus and potassium removal and leaching from residue in corn and soybean. p. 197-202. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Nov. 16-17. Vol. 27. Des Moines, IA
• Mallarino, A.P., and D. Rueber. 2010. Phosphorus fertilization strategies for alfalfa hay, production followed by corn harvested for grain. Northern Research and Demonstration Farm Annual Reports. RFR-A9108. ISRF09-22. Iowa State Univ., Ames, IA.
• Mallarino, A.P. 2009. Phosphorus and potassium placement methods for corn and soybean: an Iowa perspective. p. 109-115. In Proc. 2009 Wisconsin Crop Management Conf., Madison, WI. Vol. 48. Univ. Wisconsin-Extension and College of Ag. And Life Sciences, Univ. of Wisconsin-Madison, WI.
• Mallarino, A.P. 2009. Long term phosphorus studies and how they effect recommendation philosophies. p. 5-12. In Proc. Thirty-Ninth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA. 18-19 Nov. 2009. Vol. 25. International Plant Nutrition Inst., Brookings, SD.
• Mallarino, A.P. 2008. Fertilizing crops in the new price age - phosphorus and potassium. p. 261-266. In Proc. 20th Annual Integrated Crop Manag. Conf., Ames, IA. 10-11 Dec. 2008. Iowa State Univ., Ames, IA
• Mallarino, A.P., and J. Prater. 2007. Corn and soybean grain yield, phosphorus removal, and soil-test responses to long-term phosphorus fertilization strategies. In Proc. 19th Annual Integrated Crop Manag. Conf., Ames, IA. 28-29 Nov. 2007. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and D.J. Wittry. 2006. Variable-rate application for phosphorus and potassium: impacts on yield and nutrient management. p. 219-224. In Proc. 18th  Annual Integrated Crop Manag. Conf., Ames, IA. 29-30 Nov. 2006. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and R. Borges. 2005. Broadcast and deep band placement of phosphorus for soybeans managed with ridge tillage. Better Crops Plant Food 89(1):8-11.
• Mallarino, A.P., M.U. Haq, and K. Pecinovsky. 2005. Runoff phosphorus loss as affected by tillage, fertilizer, and swine manure phosphorus management in corn-soybean production systems. p. 46-47. In Annual progress reports-2004. Northeast research and demonstration farm. ISRF04-13. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and D. Rueber. 2005. Phosphorus and potassium fertilization and placement methods for corn-soybean rotations managed with no-till and chisel plow tillage. p. 12-13. In Annual progress reports-2004. Northern Research and Demonstration farm. ISRF04-22. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and K. Pecinovsky. 2005. Phosphorus and potassium placement methods for corn and soybeans managed with no-till and chisel plow tillage. p. 44-45. In Annual progress reports-2004. Northeast research and demonstration farm. ISRF04-13.
• Mallarino, A.P. 2004. On-farm implementation of the phosphorus index: Observed risk ratings and impacts on fertilizer and manure phosphorus management. p. 145-152. In The Integrated Crop Management Conf. Proceedings. Dec. 1-3, Ames, IA. Iowa State Univ. Extension.
• Mallarino, A.P., and K. Pecinovsky. 2004. Long-term phosphorus and potassium fertilization strategies for corn-soybean rotations. p. 22-23. In Annual progress reports-2003. Northeast research and demonstration farm. ISRF03-13. Iowa State Univ., Ames, IA.
• Kanwar, R., J. Baker, C. Pederson, A.P. Mallarino, J. Sawyer, and K. Pecinovsky. 2004. Impact of swine manure applications on nitrate and phosphorus in subsurface drainage water. p. 26-27. In Annual progress reports-2003. Northeast research and demonstration farm. ISRF03-13. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and D. Rueber. 2004. Long-term phosphorus fertilization for corn-soybean rotations. p. 12-13. In Annual progress reports-2003. Northern Research and Demonstration farm. ISRF03-22. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and D. Haden. 2004. Phosphorus and potassium placement for corn and soybeans managed with no-till and chisel-disk tillage. p. 14-15. In Annual progress reports-2003. Northwest research and demonstration farm. ISRF03-29,31. Iowa State Univ., Ames, IA.
• Mallarino, A.P., B. Havlovic, and J. Butler. 2004. Phosphorus and potassium fertilizer placement for corn and soybeans managed with no-till and chisel-disk tillage. p. 19-20. In Annual progress reports-2003. Armstrong research and demonstration farm. ISRF00-12. Iowa State Univ., Ames, IA.
• Mallarino, A.P., J. Sawyer, J. Klatt, R. Kanwar, C. Pederson, J. Baker, and K. Pecinovsky. 2003. Fertilizer and swine manure management systems: impacts on agronomic and environmental soil phosphorus tests and on phosphorus loss with subsurface drainage. Annual progress reports-2002. Northeast Research and Demonstration farm. ISRF02-13. Iowa State Univ., Ames, IA.
• Mallarino, A.P. 2003. Starter and foliar fertilization. Are they needed to supplement primary fertilization? p. 113-120. In The Integrated Crop Management Conf. Proceedings. Dec. 3-4, Ames, IA. Iowa State Univ. Extension.
• Mallarino, A.P. 2003. Using the Iowa phosphorus index for agronomic and environmental management of fertilizer and manure phosphorus. p. 121-126. In The Integrated Crop Management Conf. Proceedings. Dec. 3-4, Ames, IA. Iowa State Univ. Extension.
• Kaiser, D.E., A.P. Mallarino, and M. Bermudez. 2003. In-furrow starter and broadcast phosphorus and potassium fertilization for corn. p. 186-189. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Vol. 19. Des Moines, IA.
• Mallarino, A.P., and D. Rueber. 2003. Long-term evaluation of nitrogen, phosphorus, potassium, and lime requirements of continuous corn. p. 7-8 In Annual progress reports-2002. Northern Research and Demonstration farm. ISRF02-22. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and K. Van Dee. 2003. Phosphorus and potassium placement for corn and soybeans managed with no-till and chisel-plow tillage. Annual progress reports-2002. Northwest Research and Demonstration farm. ISRF02-34. Iowa State Univ., Ames, IA.
• Klatt, J.G., A.P. Mallarino, and B.L. Allen. 2002. Relationships between soil phosphorus and phosphorus in surface runoff and subsurface drainage. An overview of ongoing research. p. 183-189. In North-Central Extension-Industry Soil Fertility Conf. Proceedings. Vol. 18. Des Moines, IA.
• Mallarino, A.P., D. Wittry, and J. Klatt. 2001. Using the Iowa phosphorus index and variable-rate technology for effective agronomic and environmental phosphorus management. p. 151-158. 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.
• Sawyer, J.E. and D. Barker. 1999. Foliar fertilization of corn with mono-potassium phosphate and urea. Final research report. Iowa State Univ., Ames, IA
• Mallarino, A.P. 1999. Alternatives for P and K management: A role for deep banding and starter? p. 247-253. In The Integrated Crop Management Conference. Proceedings. Dec. 1-2, 1999. Iowa State Univ. Extension. Ames, IA.
• Mallarino, A.P. 1999. Soil phosphorus testing for crop production and environmental purposes. p. 185-192. In The Integrated Crop Management Conf. Proceedings. Dec. 1-2, 1999. Ames, IA. Iowa State Univ. Extension.
• Mallarino, A.P., and D. Rueber. 1998. Evaluation of superphosphate and rock phosphate for a corn-oat-forage rotation. p. 6-8. In Annual progress reports-1997. Northern research and demonstration farm. ISRF97-22. Iowa State Univ., Ames, IA.
• Mallarino, A.P., and Haq, M.U. 1998. Foliar fertilization of soybeans. p. 20-26. In North Central Extension-Industry Soil Fertility Conference. Proceedings. Vol. 14. St. Louis, MO.
• Mallarino, A.P., D.W. Barker, R. Borges, and J.C. North. 1998. Tillage and fertilizer placement for the corn-soybean rotation. p. 231-237. In The Integrated Crop Management Conference. Proceedings. Nov. 17-18, 1998. Iowa State Univ. Extension, Ames, IA.
• Mallarino, A.P., D.J. Wittry, D. Dousa, and P.N. Hinz. 1998. Variable-rate phosphorus fertilization: On-farm research methods and evaluation for corn and soybean. p. 687-696. In P.C. Robert et al. (ed.). Proceedings, 4d. Int. Conf. on Site-Specific Management for Agricultural Systems. July 19-22, 1998 Minneapolis, MN. ASA, SSSA, ASA. Madison, WI.

Featured Publication

Links

• Iowa NRCS Phosphorus Index
• Iowa Department of Natural Resources, Animal Feeding Operations
• SERA 17 - Minimizing Phosphorus Losses from Agriculture

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