Relationships Between Ear-Leaf Nutrient Concentrations at Silking and Corn Biomass and Grain Yields at Maturity

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  • Ear-leaf nutrient concentrations at silking correlated strongly with corn grain yield.
  • Ear-leaf nutrient concentrations at silking correlated strongly with whole-plant biomass.
  • Ear-leaf N, P, S, Cu, and Fe concentrations explained most of the grain yield variation.
  • State recommendations for certain minimum nutrient concentrations may need adjustment.

Historically, corn (Zea mays L.) ear-leaf N concentrations at mid-silking have been positively correlated with grain yield (GY). Many state and regional fertilizer recommendations provide “nutrient sufficiency ranges” or threshold nutrient concentrations for N and other nutrients in ear leaves sampled at silk emergence, but these are based on studies conducted decades ago with much lower yielding hybrids grown at lower plant densities. In response to this potential knowledge gap, we collected corn ear-leaf samples at mid-silking in field studies conducted near West Lafayette, IN, from 2010 to 2016. These field studies involved comparisons of multiple hybrids, plant densities or tillage systems for their response to nutrient management alternatives (e.g., macronutrient rates, placement, and timing). The ear-leaf samples were analyzed for nutrient concentrations (N, P, K, Ca, Mg, S, Zn, Mn, Fe, Cu, B, and Al), and each plot's nutrient concentration data were subjected to regression analysis to evaluate their relationship with plot level dry matter (DM) accumulation and GY responses. Variation in ear-leaf N, P, S, and Cu concentrations explained >50%, while Fe explained >40%, of the variation in both GY and DM. These nutrients (N, P, S, Cu, and Fe) were also positively correlated with each other (Pearson r ranged from 0.46–0.89). However, ratios of ear-leaf nutrient concentrations at silking consistently explained less of the GY variation than single nutrient concentrations. The overall relationships of ear-leaf nutrient concentrations with GY suggests revisions in state recommendations for ear-leaf “nutrient sufficiency” may be warranted for some nutrients.



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Creative Commons Attribution-Share Alike 4.0 International License
This work is licensed under a Creative Commons Attribution-Share Alike 4.0 International License.