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AUTOMATED CALIBRATION STAMP TECHNOLOGY FOR IMPROVED IN‐SEASON NITROGEN FERTILIZATION
Author(s) -
Raun W. R.,
Solie J. B.,
Stone M. L.,
Zavodny D. L.,
Martin K. L.,
Freeman K. W.
Publication year - 2005
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/agronj2005.0338a
Subject(s) - sowing , fertilizer , mineralization (soil science) , nitrogen , calibration , environmental science , mathematics , agronomy , soil science , chemistry , soil water , biology , statistics , organic chemistry
Midseason fertilizer N is currently recommended using a wide range of differing soil‐test, plant‐test, and soil‐N mineralization procedures. The objective of this paper is to present an applied approach for determining midseason fertilizer N rates. A conventional 2003 Honda FourTrax Foreman ES four‐wheeler (433 cc, 127 cm wheel base, 116 cm wide) with a 3 m wide spray boom and a 1‐m spacing between nozzles was modified to deliver a range of fixed N rates as urea ammonium nitrate (28%N) within a 9 m 2 grid. Within each grid, nine separate 1 m 2 areas exist, whereby each of the four corners receive no fertilizer N. Rates of 22, 45, 67, 90, and 112 kg N ha −1 occupy the other five, 1 m 2 areas within the 9 m 2 grid (termed as an N rate calibration stamp). Traveling at 8 km h −1 (5 mph), consecutive 9 m 2 grids can be applied continuously. Calibration stamps should be applied preplant or soon thereafter and superimposed on top of the farmer practice. By midseason, differences between the 1 m 2 N rate areas can be visualized and a field‐specific topdress N rate prescribed by choosing the lowest N rate where no visual differences were observed between it and the highest rate. Calibration stamps applied preplant or soon after planting can assist in providing visual interpretation of N mineralization + atmospheric N deposition from planting to the time midseason N is applied, and improved determination of topdress N rates.