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Nitrogen fertilizer timing and application method affect weed growth and competition with spring wheat

  • Robert E. Blackshaw, Louis J. Molnar (a1) and H. Henry Janzen (a1)


Managing crop fertilization may be an important component of integrated weed management systems that protect crop yield and reduce weed populations over time. A field study was conducted to determine the effects of various timings and application methods of nitrogen (N) fertilizer on weed growth and spring wheat yield. Nitrogen fertilizer was applied the previous fall (October) or at planting (May) at a dose of 50 kg ha−1. Nitrogen application treatments consisted of granular ammonium nitrate applied broadcast on the soil surface, banded 10 cm deep between every crop row, banded 10 cm deep between every second crop row, or point-injected liquid ammonium nitrate placed between every second crop row at 20-cm intervals and 10 cm deep. Treatments were applied in 4 consecutive yr to determine annual and cumulative effects over years. Density and biomass of wild oat, green foxtail, wild mustard, and common lambsquarters were sometimes lower with spring- than with fall-applied N. Spring wheat yield was never lower and was higher in 50% of the cases, when N was spring rather than fall applied. Nitrogen application method generally had larger and more consistent effects than application timing on weed growth and wheat yield. Shoot N concentration and biomass of weeds were often lower with subsurface banded or point-injected N than with surface broadcast N, and concurrent increases in spring wheat yield usually occurred with these N placement treatments. Depending on the weed species, the weed seedbank at the conclusion of the 4-yr study was reduced by 25 to 63% with point-injected compared with broadcast N. Information gained in this study will contribute to the development of more integrated and cost-effective weed management programs in wheat.


Corresponding author

Corresponding author. Agriculture and Agri-Food Canada, Lethbridge Research Centre, P.O. Box 3000, Lethbridge, AB T1J 4B1, Canada;


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Agenbag, G. A. and Villiers, O. T. 1989. The effect of nitrogen fertilizers on the germination and seedling emergence of wild oat (Avena fatua L.) seed in different soil types. Weed Res 29:239245.
Angonin, C., Caussanel, J. P., and Meynard, J. M. 1996. Competition between winter wheat and Veronica hederifolia: influence of weed density and the amount and timing of nitrogen application. Weed Res 36:175187.
Blackshaw, R. E., Brandt, R. N., Janzen, H. H., Entz, T., Grant, C. A., and Derksen, D. A. 2003. Differential response of weed species to added nitrogen. Weed Sci 51:532539.
Blackshaw, R. E., Semach, G., and Janzen, H. H. 2002. Fertilizer application method affects nitrogen uptake in weeds and wheat. Weed Sci 50:634641.
Blackshaw, R. E., Semach, G., Li, X., O'Donovan, J. T., and Harker, K. N. 2000a. Tillage, fertiliser and glyphosate timing effects on foxtail barley (Hordeum jubatum) management in wheat. Can. J. Plant Sci 80:655660.
Blackshaw, R. E., Semach, G. P., and O'Donovan, J. T. 2000b. Utilization of wheat seed rate to manage redstem filaree (Erodium cicutarium) in a zero-till cropping system. Weed Technol 14:389396.
Cochran, V. L., Morrow, L. A., and Schirman, R. D. 1990. The effect of N placement on grass weeds and winter wheat in three tillage systems. Soil Tillage Res 18:347355.
Dhima, K. V. and Eleftherohorinos, I. G. 2001. Influence of nitrogen on competition between winter cereals and sterile oat. Weed Sci 49:7782.
Di Tomaso, J. M. 1995. Approaches for improving crop competitiveness through the manipulation of fertilization strategies. Weed Sci 43:491497.
Ervio, L. R. and Salonen, J. 1987. Changes in the weed population of spring cereals in Finland. Ann. Agric. Fenn 26:201226.
Forcella, F. 1984. Wheat and ryegrass competition for pulses of mineral nitrogen. Aust. J. Exp. Agric. Anim. Husb 24:421425.
Gonzalez Ponce, R. 1998. Competition between barley and Lolium rigidum for nitrate. Weed Res 38:453460.
Hewson, R. T. and Roberts, H. A. 1973. Some effects of weed competition on the growth of onions. J. Hortic. Sci 48:5157.
Janzen, H. H. and Lindwall, C. W. 1989. Optimum application parameters for point injection of nitrogen in winter wheat. Soil Sci. Soc. Am. J 53:18781883.
Janzen, H. H., Lindwall, C. W., and Roppel, C. J. 1990. Relative efficiency of point-injection and surface applications for N fertilization of winter wheat. Can. J. Soil Sci 70:189201.
Jornsgard, B., Rasmussen, K., Hill, J., and Christiansen, J. L. 1996. Influence of nitrogen on competition between cereals and their natural weed populations. Weed Res 36:461470.
Kirkland, K. J. and Beckie, H. J. 1998. Contribution of nitrogen fertilizer placement to weed management in spring wheat (Triticum aestivum). Weed Technol 12:507514.
Kucey, R. M. N. and Schaalje, G. B. 1986. Comparison of nitrogen fertilizer methods for irrigated barley in the northern great plains. Agron. J 78:10911094.
Liebman, M., Mohler, C. L., and Staver, C. P. 2001. Ecological Management of Agricultural Weeds. Cambridge, Great Britain: Cambridge University Press. Pp. 139209, 269–321.
Mesbah, A. O. and Miller, S. D. 1999. Fertilizer placement affects jointed goatgrass (Aegilops cylindrica) competition in winter wheat (Triticum aestivum). Weed Technol 13:374377.
Morales-Payan, J. P., Santos, B. M., Stall, W. M., and Bewick, T. A. 1998. Interference of purple nutsedge (Cyperus rotundus) population densities on bell pepper (Capsicum annuum) yield as influenced by nitrogen. Weed Technol 12:230234.
Qasem, J. R. 1992. Nutrient accumulation by weeds and their associated vegetable crops. J. Hortic. Sci 67:189195.
Rao, S. C. and Dao, T. H. 1996. Nitrogen placement and tillage effects on dry matter and nitrogen accumulation and redistribution in winter wheat. Agron. J 88:365371.
Rasmussen, P. E. 1995. Effects of fertilizer and stubble burning on downy brome competition in winter wheat. Commun. Soil Sci. Plant Anal 26:951960.
Rasmussen, K., Rasmussen, J., and Petersen, J. 1996. Effects of fertilizer placement on weeds in weed harrowed spring barley. Acta Agric. Scand. Sect. B Soil Plant Sci 45:15.
Raun, W. R. and Johnson, G. V. 1999. Improving nitrogen use efficiency for cereal production. Agron. J 9:357363.
Reinertsen, M. R., Cochran, V. L., and Morrow, L. A. 1984. Response of spring wheat to N fertilizer placement, row spacing, and wild oat herbicides in a no-till system. Agron. J 76:753756.
Roberts, T. L., Janzen, H. H., and Lindwall, C. W. 1992. Nitrogen fertilization of spring wheat by point-injection. J. Prod. Agric 5:586590.
[SAS] Statistical Analysis Systems. 1999. SAS/STAT User's Guide. Version 8. Cary, NC: Statistical Analysis Systems Institute. 3884 p.
Shipley, B. and Keddy, P. A. 1988. The relationship between relative growth rate and sensitivity to nutrient stress in twenty-eight species of emergent macrophytes. J. Ecol 76:11011110.
Steel, R. G. D. and Torrie, J. H. 1980. Multiple comparisons. Pages 173177 in Principles and Procedures of Statistics. 2nd ed. New York: McGraw-Hill.
Supasilapa, S., Steer, B. T., and Milroy, S. P. 1992. Competition between lupin (Lupinus angustifolia L.) and great brome (Bromus diandrus Roth.): development of leaf area, light interception and yields. Aust. J. Exp. Agric 32:7181.
Van Delden, A., Lotz, L. A., Bastiaans, L., Franke, A. C., Smid, H. G., Groeneveld, R. M. W., and Kropff, M. J. 2002. The influence of nitrogen supply on the ability of wheat and potato to suppress Stellaria media growth and reproduction. Weed Res 42:429445.


Nitrogen fertilizer timing and application method affect weed growth and competition with spring wheat

  • Robert E. Blackshaw, Louis J. Molnar (a1) and H. Henry Janzen (a1)


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