Improving winter wheat grain yield and nitrogen use efficiency using nitrogen application time and rate
Abstract
Preplant nitrogen (N) application which involves placing nutrients in the soil prior to seeding has been an integral part of crop production systems for decades. Some producers are known to apply N at least 21 days before planting. This may increase N loss and lower grain yield. This study evaluated the effect of time and rate of N application on winter wheat (Triticum aestivum L.) grain yield and N use efficiency (NUE). An experiment with a factorial arrangement of treatments was set up in a randomized complete block design with three replications. Treatments included four N rates (0, 45, 90 and 135 kg ha-1) with each applied 7 and 30 days before planting, and at Feekes 5 (FK5). Wheat grain was harvested using a combine. Grain N was analyzed using LECO CN 628 and LECO CN 828 for 2019 and 2020 grain harvest respectively. The difference method, [Grain N from (fertilized plots - unfertilized plots)/N applied] , was used to compute NUE. Apart from Efaw (2019), the interaction between time and rate of N application did not influence yield (P ? 0.07). Nitrogen rate significantly affected yield and increased with increasing N rates (P ? 0.01). Time of N application inconsistently affected yield and had no influence in some years. Overall, applying N at FK5 resulted in approximately 3.3% higher yield than 2.9 Mg ha-1 achieved with preplant timing. In Lahoma, single degree of freedom contrasts showed a substantial NUE difference between FK5 and 30 days before planting N application time (P = 0.03). This preplant N timing had 8.4% lower NUE compared to 24.0% for in-season management. Time and rate of N application are critical management approaches vital for yield and NUE improvement.
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- OSU Dissertations [11222]