Broadcast and subsurface-banded urea nitrogen in urea ammonium nitrate applied to corn
1991
Maddux, L.D. | Raczkowski, C.W. | Kissel, D.E. | Barnes, P.L.
Lower yields of corn (Zea mays L.) have been reported in northeastern Kansas when urea ammonium nitrate (UAN) solution is broadcast incorporated rather than subsurface banded. Broadcast incorporated and subsurface-banded 15N-tagged area in UAN were evaluated in 1982 and 1983 for N uptake by irrigated corn and N immobilization by a Eudora silt loam (coarse-silty, mixed, mesic Fluventic Hapludoll). Uptake of N in corn plant components and residual inorganic and immobilized tagged ares N were measured, and an N balance calculated. Recovery of tagged urea N by all plant components was 61 and 68% for banded UAN in 1982 and 1983, respectively, but only 39 and 44% for broadcast incorporated UAN. The amount of tagged area N immobilized in the top 90 cm of the soil profile was 58 and 14% greater with the broadcast incorporated than with the banded treatment for 1982 and 1983, respectively. Tagged urea N that was unaccounted for was 62 and 200% greater, respectively, for the 2 yr with the broadcast than with the banded applications. The difference in unaccounted-for tagged N between treatments was attributed to variations in loss by leaching. The differences in uptake of tagged urea N were attributed to a combined effect of greater soil immobilization and loss by leaching with the broadcast incorporated application.
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