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Characterizing and Classifying Variability in Corn Yield Response to Nitrogen Fertilization on Subfield and Field Scales
Author(s) -
Kyveryga P. M.,
Blackmer A. M.,
Zhang J.
Publication year - 2009
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2008.0168
Subject(s) - yield (engineering) , fertilizer , mathematics , agronomy , nitrogen , human fertilization , field experiment , zea mays , statistics , growing season , crop yield , spatial variability , biology , chemistry , materials science , metallurgy , organic chemistry
Marked spatial and temporal variability in yield response to N fertilizer observed in individual yield response trials creates a high degree of uncertainty when estimating economic optimum rates (EORs) of N for a group of trials and when extrapolating these rates from one location to another. A survey was conducted to characterize and classify variability in yield response to N on subfield and field scales. Fertilizer N was applied at five rates (56, 84, 112, 140, and 168 kg N ha −1 ) in many (6–12) replicated strips within three 18‐ to 24‐ha no‐till fields during two corn ( Zea mays L.) growing seasons. Yield responses or yield differences between two adjacent strips were measured in 22 to 25 grid cells ha −1 within each field. Cumulative probability distributions (CPDs) were used to estimate the probability that a given N rate produces a yield response less or equal to a specified quantity. The yield responses were classified into potential categories with different N fertilizer requirements using apparent soil electrical conductivity (EC a ), digital soil map units, and relative elevation. Analysis indicated that the classifications explained <3% variability in yield response to N applied in the near‐optimal range, where probabilities of receiving positive and negative marginal returns were the same. Presenting probabilities of yield response observed at different ranges of N fertilization may provide the basis for assessing the uncertainty associated with the variable effects of weather and variable supply of N when assessing economic risk and benefits of N fertilization in large‐scale on‐farm studies.