Phalaris minor density was significantly affected by weed-crop competition durations (Table 1). There was a progressive increase in number of P. minor plants with increase in weed-crop competition duration. The maximum P. minor density (85.50) was found in plots where the weeds were allowed to compete throughout the season. No weed was recorded in weed free plots because weeds were removed frequently. Minimum numbers of P. minor plants (73.75) were found in weed-crop competition duration of 40 days after emergence. Chenopodium album density was significantly affected by different weed-crop competition durations. The maximum numbers of C. album plants (9.75) were found in weedy check. The difference between weedy check and competition for 80 days after sowing were not significant. As the competition duration increased, the number of Anagallis arvensis also increased. Maximum A. arvensis density (8.25) was found in plots where A. arvensis plants were allowed to compete with crop for 80 days after emergence. However, the difference among weedy check, 70 and 80 days after sowing were not significant. The difference among the competition periods of 40, 50 and 60 days after emergence also were not significant. Significantly higher Convolvulus arvensis density (6.50) was found in plots where C. arvensis was allowed to compete with crop throughout the growing season. The minimum number (0.75) of C. arvensis plants were found in competition duration of 40 days after emergence. Medicago denticulata plants were increased with the increase in competition duration period. Weedy check produced significantly highest number of plants of M. denticulata among all other competition periods. The competition periods of 50 days after emergence have statistically similar plants to competition period of 40 and 60 days after sowing (Table-1).
Total weed density increased significantly with the increase in competition duration and increase was significant at each increase in duration period. The maximum (117.5) and minimum (82.75) weed density was obtained in plots with competition through out the season and for 40 days after emergence, respectively Weedy check showed maximum weed density because there was longer period available for weeds to germinate and weeds continued to germinate throughout the growth period. These results are in accordance with Tunio et al. (2004). Weed free plots showed minimum density because weeds were eradicated by repeated hand hoeing (Table 1).