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Wheat and Italian ryegrass (Lolium multiflorum) competition as affected by phosphorus nutrition

  • Harry T. Cralle, Tiffany B. Fojtasek (a1), Katherine H. Carson (a1), James M. Chandler (a1), Travis D. Miller (a1), Scott A. Senseman (a1), Rodney W. Bovey (a2) and Martin J. Stone (a3)...


A greenhouse experiment used a replacement series design to compare the vegetative growth 6 wk after emergence in pure cultures and mixtures of winter wheat and Italian ryegrass, with phosphorus (P) levels recommended by soil testing. The planting proportions of wheat and Italian ryegrass were 100 and 0%, 75 and 25%, 50 and 50%, 25 and 75%, and 0 and 100%, respectively. There was no alleopathic interaction between the species. Both species in all pure and mixed cultures had substantially less growth in the low-P than in the recommended P treatment. However, the relative performance of the two species differed between P treatments. In the recommended P treatment in pure culture, Italian ryegrass had more tillers and greater root weight and length than wheat. Pure culture wheat in the low-P treatment exceeded pure culture Italian ryegrass in leaf area, weights of leaves, stems, and roots, and root length. Thus, the growth of wheat was inhibited less by P deficiency than the growth of Italian ryegrass in pure culture. In the 50:50 mixture of the recommended P treatment, wheat had greater leaf, stem, and root weights than Italian ryegrass. In the 50:50 mixture of the low-P treatment, the two species were very similar in growth, except that Italian ryegrass had about three times more tillers than did wheat. Whereas P deficiency limited the growth of wheat less than Italian ryegrass in pure culture, P deficiency did not affect the relative competitiveness of Italian ryegrass as much as wheat in mixed cultures. The ability of Italian ryegrass to compete with wheat when P was limiting may result from a difference in root growth. Italian ryegrass had a greater fresh root length to fresh root weight ratio than did wheat in the low-P treatment in pure culture and in the 50:50 mixture. The greater surface area of Italian ryegrass roots likely enhanced the competitiveness of Italian ryegrass relative to wheat under P-deficit conditions. Thus, the use of the recommended P nutrition from soil testing may be a key component to diminish Italian ryegrass competition in wheat fields.


Corresponding author

Corresponding author. Department of Soil and Crop Science, Texas A&M University, College Station, TX 77845;


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Appleby, A. P. and Brewster, B. D. 1992. Seeding arrangement of winter wheat (Triticum aestivum) grain yield and interaction with Italian ryegrass (Lolium multiflorum). Weed Technol. 6:820823.
Appleby, A. P., Olson, P. D., and Colbert, D. R. 1976. Winter wheat yield reduction from interference by Italian ryegrass. Agron. J. 68:463466.
Carson, K. H., Cralle, H. T., Chandler, J. M., Miller, T. D., Bovey, R. W., Senseman, S. A., and Stone, M. J. 1999. Triticum aestivum and Lolium multiflorum interaction during drought. Weed Sci. 47:440445.
Claassen, N. and Jungk, A. 1988. Phosphorus efficiency of plants. Plant Soil. 110:101109.
Goodman, P. J. and Collison, M. 1981. Uptake of 32-P labeled phosphate by clover and Italian ryegrass growing in mixed swards with different nitrogen treatments. Ann. Appl. Biol. 98:499506.
Goodman, P. J. and Collison, M. 1982. Varietal differences in uptake of 32-P labeled phosphate in clover plus Italian ryegrass swards and monocultures. Ann. Appl. Biol. 100:559565.
Halvorson, A. D. and Havlin, J. L. 1992. No-till winter wheat response to phosphorus placement and rate. Soil Sci. Soc. Am. J. 56:16351639.
Harper, J. L. 1977. Population Biology of Plants. London: Academic Press. pp. 255267.
Hashem, A., Radosevich, S. R., and Roush, M. L. 1998. Effect of proximity factors on competition between winter wheat (Triticum aestivum) and Italian ryegrass (Lolium multiflorum). Weed Sci. 46:181190.
Liebl, R. and Worsham, A. D. 1987. Interference of Italian ryegrass (Lolium multiflorum) in wheat (Triticum aestivum). Weed Sci. 35:819823.
Miller, T. D. 1998. Deep Phosphorus Banding in Winter Wheat: A Risk Management Tool for the Southern Great Plains. College Station, TX: Texas Agricultural Extension Service Publication #SCS-1998-27.
Radosevich, S. R. 1987. Methods to study interactions among crops and weeds. Weed Technol. 1:190198.
Stone, M. J., Cralle, H. T., Chandler, J. M., Miller, T. D., and Bovey, R. W. 1999. Wheat yield loss in response to diverse environments. J. Prod. Agric. 12:229231.
Stone, M. J., Cralle, H. T., Chandler, J. M., Miller, T. D., Bovey, R. W., and Carson, K. H. 1998. Above- and below-ground interference of wheat (Triticum astivum L.) and Italian ryegrass (Lolium multiflorum Lam.). Weed Sci. 46:438441.



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