Agropyron repens ‐ allelopathy?

Following the work of Becholtz and Bandeen, a series of glasshouse experiments was made to examine the effects of root‐zone interference between Agropyron repens and wheat. In a solution‐culture experiment the reduction in growth of wheat due to the presence of A. repens could be largely corrected by increasing the nutrient supply in the solution. In similar studies but using soils, the depression of growth of wheat could not be corrected. Foliage applications of nitrogen to wheat plants grown with A. repens had no effect. Using a split‐pot technique it was found that the part of the root system of wheat growing in the same medium as the rhizomes and roots of A. repens was very severely suppressed. These results will be discussed.