Northeast Research and Demonstration Farm

In-Season Nitrogen Fertilization of Soybean

Authors: John E. Sawyer (Iowa State University) , Daniel W. Barker (Iowa State University)

  • In-Season Nitrogen Fertilization of Soybean

    Northeast Research and Demonstration Farm

    In-Season Nitrogen Fertilization of Soybean

    Authors: ,

Abstract

Nitrogen (N) fertilization is not a traditional nutrient management practice for soybean production in Iowa. Soybean is a legume plant and is assumed to adequately obtain needed N through symbiotic fixation. However, there is interest in using N fertilization to increase yield and grain protein due to the recognition of the large N requirement associated with high yields. Despite the fact that soybean is a legume, it readily utilizes soil inorganic N and will do so preferentially to symbiotic N2 fixation. Depending on the residual inorganic N level and soil N mineralization characteristics, approximately 40 to 75% of the N in a mature soybean plant is derived from the soil. Also, soybean seems to require this soil derived N for high yield. The overall objectives of this research were to determine the impact of soil applied N fertilizer at the beginning pod stage (R3) of soybean growth on grain yield and quality components. Additional objectives were to study response to N fertilizer placement, material (N release characteristic), and rate.

Keywords: Agronomy

How to Cite:

Sawyer, J. E. & Barker, D. W., (2001) “In-Season Nitrogen Fertilization of Soybean”, Iowa State University Research and Demonstration Farms Progress Reports 2000(1).

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Published on
01 Jan 2001
Peer Reviewed