Is soybean yield limited by nitrogen supply

By N. C. L. Menza, J. P. Monzon, J. Specht, P. Grassini. 2017

153 citations recorded by the source corpus.

Abstract As soybean yield continues to increase, it seems critical to know if there is a yield level at which potential contribution of indigenous nitrogen (N) sources (N fixation and soil mineralization) becomes insufficient to meet crop N requirements for high yields, while still maintaining or increasing protein and oil concentration. We have hypothesized that, in absence of other limiting factors, degree of N limitation increases with increasing yield potential (Yp) of the production environment. To test this hypothesis, we developed a novel protocol to ensure an ample N supply during the entire crop season (full-N treatment). That protocol was applied to field-grown irrigated soybean in Balcarce (Argentina) and Nebraska (USA), where measured full-N seed yields were ±15% of their simulated Yp in 92% of the cases. The combination of locations, years, sowing dates, and N treatments resulted in a wide range of seed yields, from 2.5 to 6.5 Mg ha −1 . Overall, full-N seed yield averaged 11% higher than seed yield without N addition (zero-N). However, magnitude of yield difference between full-N and zero-N depended upon Yp, ranging from no detectable yield difference in low-Yp ( ca. 2.5 Mg ha −1 ) to up to 900 kg ha −1 in high-Yp environments ( ca. 6 Mg ha −1 ). Seed yield differences were associated with higher aboveground dry matter, seed number, and seed weight in the full-N versus zero-N treatments. Seed protein (but not oil) concentration was higher in the full-N treatment, and both protein and oil yields were higher in the full-N versus zero-N treatments. Findings from this study indicate that (i) N limits soybean seed yield (as well as protein yield, and oil yield) in environments with high Yp, where indigenous N sources seem insufficient to fully satisfy crop N requirements, and (ii) yield response to N fertilizer can occur above a 2.5 Mg ha −1 Yp threshold and has an upper limit of 250 kg seed per Mg increase in Yp.

Subfields: Agronomy and Crop Science, Plant Science

View Paper: https://www.semanticscholar.org/paper/915398bd99e3c959f2ea6dd264a9290955c81623

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In Agronomy and Crop Science

  1. Shawn P. Conley
  2. Chad D. Lee

In Plant Science

  1. G. Kaur
  2. Shawn P. Conley
  3. Chad D. Lee

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