Effect of leaf litter of poplar on Phalaris minor weed

The effect of aqueous extracts of popular (Populus deltoides) trees was stu died on germination and growth of Phalaris minor, a major weed of wheat cro p. The extracts from partially decomposed leaves of poplar significantly re duced the germination and growth of Phalaris minor as compared to control. The magnitude of reduction was greater during the initial stages of decompo sition. Irrespective of decomposition stage, intensity of inhibitory effect increased with higher concentration of extract. The extract of soil up to a distance of 3 m from the tree base of three years old plantation, also si gnificantly decreased the germination and seedling growth of P. minor, whic h further intensified and extended up to 6 m in the fourth year. Thus, it c an be inferred that presence of allelochemicals in leaves and in soil under neath the poplar tree reduced the germination as well as suppressed the gro wth of P, minor and effect was more pronounced with advancement of tree age .