Abstract:
The scarce and low nutritive livestock forage resource base in semi arid Kenya limits livestock production in these regions. The major factor contributing to this situation is inadequate and erratic rainfall patterns accompanied by long dry spells often culminating into drought. To exploit the full potential of the ASALs for livestock production there is need to expand the forage resource base through introduction of climate smart forage species. This study was carried out to evaluate the growth of Brachiaria grass cultivars, seasonal herbage yield and quality in semi arid regions of Eastern Kenya. It was conducted at Kenya Agricultural Research Institute, (now Kenya Agricultural and Livestock Research Organisation) Katumani, Machakos. Brachiaria cultivars namely B. decumbens cv. Basilisk, Brachiaria hybrid Mulato II, four Brachiaria brizantha cultivars Marandu, Xaraes, BRS Piata, MG4 and two Brachiaria humidicola cultivars Humidicola and Llanero were assessed in their performance with reference to establishment rates ,dry matter yields, chemical and nutritive composition. Rhodes grass (Chloris gayana KAT R3) and Napier grass (P. pupureum cv. Kakamega I) were included as controls. In the first experiment germination percentages of the cultivars under controlled conditions in the laboratory over a period of 14 days were established alongside seedling vigour. The experimental set up involved soaking seed in concentrated sulphuric acid (> 95%) for 10 minutes and another set of the same seed in water only as controls. The second experiment involved two phases namely field establishment phase and production phase. Field establishment of the cultivars was carried out in a randomized complete block design with four replications. Plant production parameters and attributes which include plant numbers, heights, spread, plant tiller number and plant cover were monitored up to 16 weeks post seedling emergence. A standardization cut was carried out on all the plots at the end of this period and dry matter yields determined. The production phase involved measuring of the same plant attributes and chemical analysis of forage samples harvested at 6, 8 and 12 weeks regrowths after standardization. Treatment of the seeds with Concentrated sulphuric acid (> 95%) had no significant effect (p>0.05) on germination percentage. Cultivars Marandu, MG4 and Brachiaria hybrid Mulato II had similar germination percentage and were superior to the rest of the cultivars. Brachiaria brizantha cultivars Marandu, MG4 and Piata demonstrated superior seedling vigour. All the growth parameters measured varied significantly (p