Effectiveness of Seedrow-Placed N with Polymer-Coated NTP -Treated Urea for Canola and Wheat.

Malhi, S.S. and Lemke, R.L. (2013). "Effectiveness of Seedrow-Placed N with Polymer-Coated NTP -Treated Urea for Canola and Wheat.", Journal of Plant Nutrition, 36(14), pp. 2205-2224. doi : 10.1080/01904167.2013.836227  Access to full text


Seedrow-placed urea minimizes soil disturbance in reduced tillage systems, but it generally decreases seedling emergence (or stand density) at nitrogen (N) rates adequate for optimum crop yield. Two three-year field experiments were conducted on canola (Brassica napus L.) and spring wheat (Triticum turgidum L.) at Melfort Research Farm, Saskatchewan, Canada, to determine the influence of N rate (40, 80 and 120 kg N ha1), N source [untreated urea (urea), polymer-coated urea (ESN), and urea treated with Dicyandiamide (DCD) and N-(n-butyl) thiophosphoric triamide (NBPT or Agrotain{SUP}T{/SUP}{SUP}M{/SUP}) (SuperU) in 2007, or NBPT only (AgrotainU) in 2008 and 2009], and placement (side-banded N and seedrow-placed N, using knives to create 2 cm wide band), plus a zero-N control, on seedling emergence, seed and straw yield, protein concentration (PC) in seed, and N uptake in seed and straw. For both crops, side-banded N had no detrimental effect on seedling emergence compared to the zero-N control for all rates and sources. Seedrow-placed ESN had little or no effect on seedling emergence of wheat or canola. Conversely, seedrow-placed urea, SuperU or AgrotainU reduced seedling emergence for wheat at the 80 and 120 kg N ha1 rates and reduced canola seedling emergence substantially at all rates, but particularly at the 80 and 120 kg N ha1. Seed yield and N uptake were generally greater with ESN than urea and also SuperU or AgrotainU, when the fertilizers were seedrow-placed at high N rates. The findings suggest the effectiveness of ESN in providing greater seedrow-placed N application options for producers.

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