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Agronomy Journal Abstract - Nitrogen Management

Pre-Sidedress Nitrate Test and Other Crop-Based Indicators for Fresh Market and Processing Sweet Corn


This article in AJ

  1. Vol. 99 No. 1, p. 174-183
    Received: Jan 31, 2006

    * Corresponding author(s): mab@agr.gc.ca
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  1. B. L. Ma *a,
  2. K. D. Subedia and
  3. T. Q. Zhangb
  1. a Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre (ECORC), Central Experimental Farm, 960 Carling Ave., Ottawa, ON, Canada K1A 0C6
    b Agriculture and Agri-Food Canada, Greenhouse and Processing Crops Research Centre, 2585 County Rd. 20, Harrow, ON, Canada N0R 1G0


Commercial sweet corn (Zea mays L.) production requires significant quantities of fertilizer N, leading to inefficient N use and negative environmental impact. A field experiment was conducted for 4 yr (2001–2004) in Ottawa, Canada, to assess and compare presidedress soil nitrate test (PSNT) with some crop-based measurements (canopy reflectance, leaf chlorophyll and plant total N) for improved N management. A fresh market sweet corn (FMSC, hybrid ‘Temptation’) grown from 2001 to 2003, and a processing sweet corn (PSC, hybrid ‘Hollywood’) from 2002 to 2004, both received five fertilizer N rates (0, 50, 100, 150, and 200 kg N ha−1). Soil samples taken from the V4 to V8 growth stages were analyzed for NO3 –N. Leaf chlorophyll content (SPAD) and canopy reflectance were also measured for FMSC at the same time. All N treatments affected the number of marketable ears, kernel dry weight and total biomass production. However, in most cases, there was no difference between N treatments from 100 to 200 kg ha−1 The PSNT NO3 –N increased linearly with the fertilizer N rates, and there were significant positive correlations between PSNT at V4 to V6 and the number of marketable ears. It was evident that PSNT, plant N concentration at V6, SPAD and canopy reflectance all differentiated sweet corn N response similarly, and they were highly correlated with one another. We concluded that PSNT at V4 to V6 was effective in predicting sweet corn N requirement in this cool and short-growing region.

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