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Corn Yield Response to Nitrogen at Multiple In‐Field Locations
Author(s) -
Schmidt John P.,
DeJoia Aaron J.,
Ferguson Richard B.,
Taylor Randal K.,
Young R. Kris,
Havlin John L.
Publication year - 2002
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/agronj2002.7980
Subject(s) - yield (engineering) , agronomy , field corn , precision agriculture , center pivot irrigation , environmental science , nitrogen , field experiment , growing season , field (mathematics) , zea mays , mathematics , agriculture , zoology , irrigation , biology , ecology , chemistry , pure mathematics , metallurgy , organic chemistry , materials science
Improving N management for corn ( Zea mays L.) production with precision agriculture technologies requires that spatial N recommendations adequately represent in‐field variability in N availability. Our objective was to evaluate corn response to increasing N rates in several in‐field locations that represented the range of soil organic matter (OM) content in the field. In a 2‐yr study, three center pivot–irrigated fields were selected in south‐central Kansas and south‐central Nebraska. Four or five locations were selected within each field. At each location, five or six N treatments (0–336 kg N ha −1 ) were surface‐applied early in the growing season. The minimum N rate to achieve maximum yield varied by as much as 130 kg N ha −1 among in‐field locations at three site‐years. The least amount of N to achieve maximum yield did not coincide with locations representing greater soil OM. Yield response at two site‐years was the same among in‐field locations; however, mean yield among in‐field locations varied by as much as 4.2 Mg ha −1 , representing potential for improvement in N use efficiency. Leaf tissue N was below the critical threshold for 60 to 100% of observations at three different in‐field locations but below the critical threshold for <35% of the observations at all other in‐field locations. The reason for the discrepancy in N availability among in‐field locations was not conclusively identified but was not only related to soil OM content. Variable N recommendations based only on soil OM is too simplistic to reflect variability in N availability within a field.