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THE EFFECTS OF TILLAGE, RESIDUE PLACEMENT, NITROGEN RATE AND APPLICATION METHOD ON PRODUCTION, SOIL NITROGEN AND FERTILIZER NITROGEN UPTAKE OF IRRIGATED CORN (TEMPERATURE, MINERALIZATION, IMMOBILIZATION)
Abstract
Growth and nitrogen (N) uptake by irrigated corn were studied in response to tillage, residue placement, nitrogen (N) rate and method of N application treatments on Hastings silt loam and Sharpsburg silty clay loam soils in 1981 and 1982. Whole plot factorial combinations of conventional tillage (disking the soil twice) and no tillage with residues removed and with surface residues were combined with split plot applications of 56, 112 and 168 kg/ha N. Nitrogen rates were applied as ammonium nitrate either broadcast at planting or sidedressed in a band at 6-leaf growth stage as the split-split plot treatment. An application of N-15 depleted ammonium nitrate to subplots was utilized to evaluate fertilizer and soil N uptake by the crop. Surface residues, compared to residues removed, reduced grain yield 650 kg/ha and lowered grain to stover ratios 14% over three location-years. A tillage by residue interaction was realized in two of these three location-years. The interaction was characterized by reduced grain yield for surface residue treatments with an average 760 kg/ha additional reduction for surface residues combined with conventional tillage. Conversely, with residues removed, conventional tillage averaged 400 kg/ha more grain yield than no tillage. Fertilizer N uptake by the crop was increased 13.4% with 56 kg/ha sidedressed N. Grain yield was not influenced by the method of N application. An additional 2.8 and 4.2 kg fertilizer N/ha from the 56 kg/ha N rate was recovered by corn grown with residues removed or without tillage, compared to surface resides and conventional tillage treatments, respectively. Soil N uptake by the crop was generally not affected by the treatments. Warmer soil temperatures with the residues removed treatments appear to be responsible for better grain yields and greater grain to stover ratios, compared to residue-covered plots. Reduced fertilizer N uptake by the residue-covered crop was related to increased contact of fertilizer N with crop residues.
Subject Area
Agronomy
Recommended Citation
GATLIFF, EDWARD GILLUS, "THE EFFECTS OF TILLAGE, RESIDUE PLACEMENT, NITROGEN RATE AND APPLICATION METHOD ON PRODUCTION, SOIL NITROGEN AND FERTILIZER NITROGEN UPTAKE OF IRRIGATED CORN (TEMPERATURE, MINERALIZATION, IMMOBILIZATION)" (1985). ETD collection for University of Nebraska-Lincoln. AAI8526592.
https://digitalcommons.unl.edu/dissertations/AAI8526592