Abstract
In-season N fertilization is increasingly being used as a management strategy to reduce risk of N loss to the environment. This study evaluated the optimal timing for a split N fertilizer application in corn (Zea mays L.) across different environments and soil textural classes in Minnesota. Treatments consisted of pre-plant (PP) urea applied at 0 to 270 or 315 kg N ha–1 on increments of 45 kg N ha–1 and five split applications (SA) of 45 kg N ha–1 urea ammonium nitrate as starter fertilizer and 90 kg N ha–1 of urea with an urease inhibitor applied at the V2, V4, V6, V8, or V12 stage of corn phenological development. Site-years were grouped according to grain yield response to fertilizer timing. Irrigated coarse-textured soils produced 1.5- to 1.9-fold greater grain yield when fertilizer was split applied from V4 to V12 due to improved synchrony of N availability to crop demand and reduced potential for NO3–N leaching. Rainfed, fine-textured soils had mixed results. Site-years receiving welldistributed precipitation produced greater grain yield when fertilizer was split applied from V2 to V8, but early season N deficiency reduced yield for the V12 application. Site-years with limited precipitation during the late vegetative through grain filling stages of corn had no improvement in grain yield or N use efficiencies for SA because dry soil conditions likely interfered with root development and made N fertilizer positionally unavailable to the crop. This study highlights that the success of SA is largely dictated by soil texture and precipitation.
Original language | English (US) |
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Pages (from-to) | 2018-2030 |
Number of pages | 13 |
Journal | Agronomy Journal |
Volume | 111 |
Issue number | 4 |
DOIs | |
State | Published - Jul 1 2019 |