Competitiveness of selected pasture plant species with parthenium weed

A study was conducted to investigate competitiveness of pasture species grown in combination with parthenium weed (Parthenium hysterophorus L.) at varying density levels at Tony farm, Haramaya University in Ethiopia using a factorial Randomized Complete Block Design. The treatments consisted of 10, 20 and 30 plants of either Cenchrus ciliaris, Chloris gayana, Desmodium intortum, Lablab purpureus or Panicum coloratum grown together with 30, 20 or 10 parthenium plants other than pure plots of each. The test species showed a significant (P < 0.05) inhibition efficiency (IE) on the dry matter biomass (DMB), height, number of tillers, and or branches and leaf area of parthenium. Among the species, C. ciliaris, C. gayana and P. coloratum were strongly suppressive (>50% IE) whereas D. intortum and L. purpureus were ranked as moderately suppressive (<50% IE). The species had 59, 68, 73, 36 and 47% IE at heavier density, 39, 52 47, 21 and 25% at medium, and 11, 19 18, 9 and 13% at lower density levels, respectively. Similarly, at heavier densities, a reduction of 39, 44 and 52% on height, 30, 41 and 40% on number of tillers and/or branches and 24, 30 and 36% on the leaf area was recorded, respectively. At this density, the species had a higher value of 2.57, 1.69 and 2.33 relative crowding coefficient (RCC) and a positive numerical value of 0.61, 0.52 and 0.68 aggresivity index (AI), respectively. Moreover, the species produced good DMB from 255 to 348 g/plot at pure culture. There was a strong association between IE and morphological attributes with a correlation coefficient value r = 0.848, 0.795, 0.549 and 0.413 between DMB, height, number of tiller and/or branch and leaf area, respectively. The results suggest that successful management of parthenium can be achieved through a biological approach using competitive pastures species in infested rangelands and/or other locations.