Recovery of ¹⁵N-labeled fertilizer by spring bread wheat at different N rates and application times

Abstract

Tran, T. S. and Tremblay, G. 2000. Recovery of 15 N-labeled fertilizer by spring bread wheat at different N rates and application times. Can. J. Soil Sci. 80: 533-539. Optimal N fertilization can improve the yield and quality of spring bread wheat in eastern Canada. This study aimed to determine the economical N rate for the production of spring bread wheat (Triticum aestivum L. 'AC Pollet') and to compare the effect of application times on the efficiency of fertilizer N use. The experiment was conducted during 2 yr on two sites of Sainte-Rosalie clay loam. The experimental treatments were arranged in a split-plot design with N rates (0, 30, 60, 90, 120, 180 kg ha -1 ) as the main plots and the application times of fertilizer N ( 15 NH 4 15 NO 3 applied at seeding and booting stages) as the subplots. Grain yield, grain protein concentration and straw N content of wheat were increased significantly with N application rates. The economic N rates were 90 and 120 kg ha -1 for 1993 and 1994, respectively. The recovery of 15 N-labeled fertilizer (%FNR) in grain and straw was higher when applied at booting stage than at seeding in both years. In 1993, FNR varied from 37.8 to 45.7% for seeding and from 62.1 to 68.4% for booting stage treatments. The respective values were 23.1 to 30.4% and 41.3 to 50.7% in 1994. At each N rate, the proportion of N derived from fertilizer (Ndff) was higher in grain than that in straw when 15 N fertilizer was applied at booting stage. The combined recovery of 15 N fertilizer (% total FNR) applied at seeding and booting, as determined by the isotopic and the difference method, was in the same range, with a mean of 49.8% and 36.2% for 1993 and 1994, respectively. Soil N supplies for wheat during the growing season were 54 and 61 kg N ha -1 in 1993 and 1994, respectively. No priming effect of added fertilizer N on the mineralization of soil N was observed.

Spring Wheat Yield and Quality Related to Soil Texture and Nitrogen Fertilization

“…Total N uptake ranged from 39 to 96 kg N ha −1 (Table 2). These values are of the same magnitude as those (53.7–132.7 kg ha −1 ) reported by Tran and Tremblay (2000;) in Québec, Canada, at N rates varying between 0 and 180 kg N ha −1 and those reported by Tiessen et al (2005; 52.2–124 kg ha −1 ) in Manitoba at N rate of 80 kg N ha −1 . The total N uptake for the N120s treatment was lower than that obtained for the N120 and N120t treatments (Table 2).…”

“…Wheat grain yield ranged from 1.5 to 2.6 Mg ha −1 and the values are comparable to those (1.5–2.9 Mg ha −1 ) obtained for spring wheat by Manning et al (2001) in a 2‐yr study done in Manitoba, Canada, using N rates varying between 0 and 135 kg N ha −1 . Grain yield levels in our study are in the same range but slightly lower than those (1.7–3.6 Mg ha −1 ) reported by Tran and Tremblay (2000) in a 2‐yr study conducted in Québec with N rates ranging from 0 to 180 kg N ha −1 . The highest N rate (N200) gave a lower grain yield than N120t which was comparable to that for N80 (Table 2).…”

Time of nitrogen application affects nitrogen use efficiency of wheat in the humid pampas of Argentina

“…In turn, this model determined that nitrate leaching would be the main N loss mechanism in the south-eastern wheat belt of the Pampas. However, the results of this experiment and those reported in the literature indicate that 45Á50% of the applied N is lost from the soilÁplant system for N applications at tillering (Sieling et al 1998;Limaux et al 1999;Tran and Tremblay 2000), and suggest that it is still possible to increase NUE.…”

Reply to Comments on “Synthetic Nitrogen Fertilizers Deplete Soil Nitrogen: A Global Dilemma for Sustainable Cereal Production,” by R.L. Mulvaney, S.A. Khan, and T.R. Ellsworth in theJournal of Environmental Quality2009 38: 2295–2314

“…The implication is that intensive inputs of synthetic N do not contribute to a long‐term humus increase but rather stimulate organic matter mineralization (Johnston and Jenkinson, 1989; Shevtsova et al, 2003) that depletes biomass N (Shen et al, 1989; Glendining et al, 1996), thereby exacerbating the long‐term loss of N‐supplying power and total N from agricultural soils. There is good reason for concern about global food security, considering the extensive evidence from 15 N‐tracer (e.g., Vos et al, 1993; Schindler and Knighton, 1999; Tran and Tremblay, 2000; Dourado‐Neto et al, 2010) and N‐response studies (see Table 6 of Mulvaney et al, 2009) that crop N uptake originates largely from the soil rather than fertilizer applied for the current growing season.…”