Changes in herbaceous vegetation attributes and nutritional quality as influenced by cutting frequencies in the enclosure of Borana rangelands, southern Ethiopia

Abstract

Herbaceous vegetation species’ responses to cutting frequencies have not been evaluated in the Borana rangelands, southern Ethiopia. The current study was investigated to determine the grass and non-grass species’ yield responses to four cutting frequencies over two years (2019 and 2020). The four treatments were cutting once after the end of the main growing season (T1), cutting every week (T2), cutting every-two weeks (T3), and cutting every-three weeks (T4). Treatments were arranged in a randomized complete block design with four replications. In total, 37 different herbaceous species comprising 15 grasses and 22 non-grasses were sampled. Treatments had a significant effect (p < 0.01) on herbaceous biomass with yield decreasing as the number of cutting frequencies increase. Herbaceous species richness was significantly (p < 0.05) high for T4. Grass biomass was significantly (p < 0.001) high for T1. T4 markedly (p < 0.05) favored non-grass species richness and diversity while T3 significantly (p < 0.05) promoted density. Subsequent cutting over years significantly (p < 0.05) affected grass species composition and biomass. Continuous application of more frequent cuttings over years significantly (p < 0.05) favored non-grass species composition and density. Of the herbaceous vegetation attributes studied, only biomass was significantly (p < 0.05) affected by subsequent application of cutting frequencies over years being high for less frequent cutting (T1). Furthermore, T1 enhanced the percentages dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) of both grass and non-grass species. T2 favored the percentage of crude protein and true in-vitro organic matter digestibility for grass and non-grass species. Our study outlines that intermediate cutting (T4) had a positive effect on herbaceous vegetation attributes and forage nutritional qualities. Hence, for short-term rangeland management in terms of plant yield and better quality, cutting every-three weeks (intermediate cutting) will be suggested when applied subsequently over years.