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Impact of Phosphorus Fertilization Strategies on Efficiency of Nitrogen Use by Corn Rotated with Soybean

Start Date: 2008
Principal Investigator: Daniel Kaiser
Organization: University of Minnesota, Department of Soil, Water, and Climate
Status: Complete

Background Info

Recent research at the University of Minnesota has provided some evidence for a potential interaction between phosphorus fertilizer application and corn response to nitrogen. With higher prices making it critical for producers to maximize every dollar spent, potential interactions between these two key nutrients need to be studied in further detail.

The goal of this project was to utilize strip trial methodology to examine crop response, and then compare how different P management strategies may interact with the use of N in different cropping rotations. Utilization of strip trials allowed researchers to analyze different soils to determine if management strategies need to be adjusted based upon factors such as drainage or P sorption capacity, which determines the ability of soil to retain applied phosphorus.


Compare crop response to P management systems based on SLAN versus BPM concepts

Study how soil properties across a landscape may interact with P management strategies

Evaluate how P management systems may affect N fertilizer use by corn rotated with soybean

Key Findings

Application of P fertilizer before corn for a two-year corn-soybean rotation significantly increased yields when soil tested “Low” to “Medium.” In areas testing “High,” there was little to no benefit from P application.

Net returns to P were the highest when soils tested “Low” to “Medium.”

There was no evidence that the optimum nitrogen rate varied between the P management strategies, and optimum N rates were near those recommended currently by the U of M.

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