Principal Investigator: Daniel Kaiser 
Organization: University of Minnesota, Soil, Water and Climate
Award Amount: $224,773
Start Date: 4/15/2015 | End Date: 12/31/2018 
Project Manager: Jeppe Kjaersgaard (Jeppe.Kjaersgaard@state.mn.us)

FINAL REPORT is available in the Minnesota Water Research Digital Library

Project Summary

This study included laboratory, field and greenhouse conducted research to:

  • Evaluate how rate and timing of phosphorus (P) application in a 2-year corn-soybean rotation affects P loss (soluble and bio-available) for different soil types;
  • Study the impact of phosphorus fertilizer management on the enrichment/depletion of soil P from soil depths greater than 6 inches using traditional soil test methods;
  • Determine the effect of P fertilizer application on the potential for P leaching in different soils;
  • Study the impacts of long-term P management on the amount of P that can be sorbed to surface (0-6 inches) and sub-surface soils (6-12 inches);
  • Correlate the Haney H3A soil extract to corn and soybean response to P; and
  • Determine if chelates could be utilized to increase P availability to crops.

The deliverables include a report summarizing the field correlation of the Haney H3A test. This report will also correlate the Haney test to the Bray P1 and Olsen test, two tests currently used for determining P fertilizer requirements. This data can be used by farmers, scientists and others to assess the value of the Haney test for determining fertilizer requirements for corn and soybean. Additionally, the research will summarize the effect of soil type and previous P fertilizer application on the amount of water extractable and bio-available P loss in sediment. Information on the amount of P that could potentially be lost due to leaching following previous P fertilizer application on different soil textures will be provided. Lastly, this project will provide results that help identify whether chelates applied to the soil could potentially increase the availability of P in the soil.