EFFECT OF MANAGEMENT PRACTICES AND HARVESTING STAGE ON BOTANICAL COMPOSITION, BIOMASS YIELD, AND NUTRITIONAL VALUE OF NATURAL PASTURE UNDER TRADITIONAL LIVESTOCK PRODUCTION SYSTEM IN THE CENTRAL HIGHLANDS OF ETHIOPIA

Abstract

Background: Natural pasture is an essential source of livestock feed worldwide, particularly in Ethiopia. Though pastureland coverage and management practices are changing over time, studies are limited in addressing the status under the dynamics of smallholder management conditions. Objective: To evaluate natural pasture botanical composition, biomass yield, and nutritional value under different management and stages of harvesting in the central highlands of Ethiopia. Methodology: The pasture was harvested at three stages (pre-flowering, mid-flowering, and after full flowering) under different management (extensive, semi-intensive  where  urea was used as a fertilizer, and seasonal grazing). Quadrats of 0.25 m² were used for herbaceous species identification, biomass yield estimation and nutritive value analysis. Chemical composition of the samples were analyzed using Near-Infrared Reflectance Spectroscopy. Results: Thirty-one herbaceous species were identified (38.71% grasses, 19.35% legumes, 9.67% sedges, and 32.26% forbs), which belong to 11 families. The total biomass yield under semi-intensive management practice  at full maturity stage was greater than seasonally grazed and extensively managed pasture. The species richness, species evenness Shannon-Wiener diversity (H’ max) and maximum possible diversity (H’max) were similar (P>0.05) under all management practices. Natural pasture condition score was fair under seasonal grazing, while the score was excellent under extensive and semi-intensive management. Metabolizable energy (ME), and in vitro organic matter digestibility (IVOMD) were higher (P<0.5) under extensive management compared to the semi-intensive management. The pasture harvested at the pre-flowering stage had higher (P<0.05) CP content, IVOMD, and ME, but low neutral detergent fiber, acid detergent fiber and acid detergent lignin values. Implications: The findings provide new insights into improving the biomass yield and quality of the pasture in semi-intensive pastureland management, and harvesting after the full flowering stage. Conclusion: This study recommended semi-intensive management and harvesting after the full flowering stage for higher pasture biomass yield, pasture condition, and nutritional value in the highlands of Ethiopia. Further study is required to investigate the combined effects of fertilizer (organic, inorganic) application and other management on biomass yield and quality of natural pasture in similar and other areas in the highlands of Ethiopia.