Indicative Effect of Soil Type and Altitude on Yield and Quality of Selected Forage Grasses in Tanzania and Kenya

Livestock production systems in East Africa depend heavily on forage resources, yet productivity and quality of available forages vary widely across agroecological zones. This study evaluated the influence of soil type and altitude on biomass production, biomass allocation, and forage quality of three improved tropical forage grasses—Massai (Megathyrsus maximus), Mestizo (a Urochloa hybrid blend), and Talisman (Urochloa hybrid)—across five experimental sites in Tanzania and Kenya. Field trials were established using a randomized complete block design with three replicates per site. Measurements included cumulative dry matter yield, root: shoot ratio, and nutritive yield expressed as metabolizable energy and crude protein per hectare. Root: shoot ratios varied significantly among species, soil types, and altitudes, with higher ratios observed in Mestizo and Talisman, clay-loam soils, and high-altitude sites. Biomass production was highest in sandy-loam soil and mid-altitude environments. Massai consistently produced the highest cumulative dry matter yield across locations. Significant genotype × environment interactions influenced both productivity and nutritive yield. Metabolizable energy and crude protein yields varied considerably among sites, emphasizing the importance of site-specific forage selection to maximize biomass production and nutritional value in East African livestock systems.