Abstract
Orchardgrass (Dactylis glomerata L.) was sown on four different dates of sowing at various densities in the field and allowed to grow without defoliation under two different weeding treatments. Growth of each population was most influenced by the date of sowing and weeding. The reaction of orchardgrass to increasing density of weed took the form of increasing mortality in the number of tillers of orchardgrass individuals. The weight of orchardgrass individuals showed closer association with their tiller numbers than their plant height. The multiplication of tillers per unit area became dependent on the density of weed with time elapsed. The results are discussed in reference to the regulation of the size of orchardgrass population in the field.
