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Posted 14 February 2003. Crop Management. ISU Extension Issues New Recommendations for Crop Nutrients Iowa State University. (January 27, 2003) - Iowa State University (ISU) Extension soil fertility specialists have updated the phosphorus (P) and potassium (K) soil test interpretations and nutrient recommendations for Iowa. These new guidelines are available in the recently revised publication "A General Guide for Crop Nutrient and Limestone Recommendations in Iowa." "We updated the recommendations to reflect results of ongoing field calibration research," says Antonio Mallarino, one of the publication's authors and ISU Extension soil fertility specialist. According to John Sawyer, ISU Extension soil fertility specialist, changes include: new soil test interpretations for K, addition of interpretative ranges for the Mehlich-3 test as determined by ICP analysis, suggestions on P and K placement and fertilization in various tillage systems, and reorganization of recommendations for forage crops and clarification of hay versus pasture forage production. "Producers should consider these revisions so they can obtain improved crop production and economic return to fertilization," says Sawyer. "With addition of the Mehlich-3 ICP method, and the four soil test methods available for determination of soil test P, it's imperative that producers know which soil test P procedure was used to generate values they receive from the laboratory so they can make the correct interpretation and P fertilization decision. If the laboratory report does not indicate which test was used, they should contact the lab or their service provider." "A General Guide for Crop Nutrient and Limestone Recommendations in Iowa" (PM 1688) can be ordered through any ISU Extension county office or by calling the ISU Extension Distribution Center at 515-294-5247. It is also available as a PDF document that can be downloaded from the ISU Extension Web site at: www.extension.iastate.edu/Publications/PM1688.pdf. For more information on a range of crop production issues visit the ISU Extension Agronomy Web site at: extension.agron.iastate.edu. Contacts: John Sawyer Antonio Mallarino Jean McGuire |