EFFECTS OF GRASS-WEED INTERACTIONS ON MORPHOECOLOGICAL TRAITS AND WEEDING BENEFITS OF RANGE GRASSES IN SOUTHERN KENYA RANGELANDS †

Abstract

Background: Weeds invasion into rangeland ecosystems is a precursor for biodiversity loss, increased soil erosion, declining wildlife habitats, and decline in carrying capacity for livestock. These weeds are fierce competitors with range grasses often possessing attributes of high seedling vigor and short life cycles compared to the grasses. Weeds invasion to a pasture land, can starve the grasses grown in the land. Objective: To investigate the competitive interactions of three range grasses with weed infestation. Methodology: The grasses evaluated were; Chloris roxburghiana (CHLORIS), Cenchrus ciliaris (CECI), and Eragrotis superba (ERASU). Four weed control regimes were applied: Continuous weeding (T1), weeding on the 8th week (T2), weeding on 10th week (T3) and the control (T4). The grass species Morpho-ecological data was collected on parameters such as; tiller density, grass height, grass density and biomass yield at the grass bloom stage. Results: A significant difference in morpho-ecological traits of all the weeding regimes was found. Continuous weed management and weeding at 8th week of establishment, respectively showed the highest performance in all the parameters measured. None-weeding management demonstrated the least performance. Implication: These research findings will help in developing a long term pasture weeds management plans to prevent encroachment of problematic weed species and to rehabilitate the already degraded rangelands. Conclusion: On all the grass species, continuous, weeding, periodic weeding at 8 weeks and 10 weeks demonstrated an increase in dry matter biomass respectively. None-weeding had the least pasture performance.