Start Date

29-11-2007 12:00 AM

Description

The prevailing phosphorus (P) management system in Iowa and the Midwest is based on soil P testing, response-based fertilizer application for low-testing soils, and removal-based fertilizer application to maintain desirable soil-test P (STP) values. Several issues are important for an effective implementation of this philosophy These include use of appropriate soil-test methods and field calibrations to determine optimum STP levels and fertilization rates, knowledge of fertilization and cropping impacts on STP over time, reliable estimates of P removal with harvest, and use of efficient fertilizer placement methods. In Iowa, continued research during the last two decades has provided yield response calibrations for the Bray-1, Olsen (or bicarbonate), Mehlich-3 colorimetric, and Mehlich-3 ICP (inductively-coupled plasma) soil test methods. Scarcer research has focused on gaining understanding of the effects of long-term fertilization strategies for corn-soybean rotations on yield, P removal with harvest, and STP trends over time. This research is important to improve the effectiveness of P management on crop production and to maintain acceptable water quality in the state of Iowa. This information will allow producers and nutrient management planners to make prudent management choices to both profit from crop production and be mindful of environmental impacts.

DOI

https://doi.org/10.31274/icm-180809-904

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Nov 29th, 12:00 AM

Corn and Soybean Grain Yield, Phosphorus Removal, and Soil-Test Responses to Long-Term Phosphorus Fertilization Strategies

The prevailing phosphorus (P) management system in Iowa and the Midwest is based on soil P testing, response-based fertilizer application for low-testing soils, and removal-based fertilizer application to maintain desirable soil-test P (STP) values. Several issues are important for an effective implementation of this philosophy These include use of appropriate soil-test methods and field calibrations to determine optimum STP levels and fertilization rates, knowledge of fertilization and cropping impacts on STP over time, reliable estimates of P removal with harvest, and use of efficient fertilizer placement methods. In Iowa, continued research during the last two decades has provided yield response calibrations for the Bray-1, Olsen (or bicarbonate), Mehlich-3 colorimetric, and Mehlich-3 ICP (inductively-coupled plasma) soil test methods. Scarcer research has focused on gaining understanding of the effects of long-term fertilization strategies for corn-soybean rotations on yield, P removal with harvest, and STP trends over time. This research is important to improve the effectiveness of P management on crop production and to maintain acceptable water quality in the state of Iowa. This information will allow producers and nutrient management planners to make prudent management choices to both profit from crop production and be mindful of environmental impacts.

 

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