Effects of soil composition and mulching treatments on biomass variations of Oxytenanthera abyssinica (A.Rich.) Munro, eastern Ethiopia

Abstract

I evaluated biomass variations of lowland bamboo (Oxytenanthera abyssinica) in Dire Dawa, Eastern Ethiopia, under different mulching and soil composition treatments. A plantation was established in June 2017 using 162 seedlings arranged in a factorial Randomized Complete Block Design (RCBD), with three blocks, six plots per block and nine seedlings per plot. Treatments included two mulching levels, mulched (W1) and non-mulched (WO), and three soil compositions: T1 (a 3:2:1 mix of local soil, animal manure, and sand), T2 (a 3:2 mix of local soil and animal manure) and T3 (a 6:2 mix of local soil and animal manure). Standard management practices were applied uniformly. Data collection was conducted in April 2022 on four-year-old bamboo stands. Growth parameters measured included culm height, number of culms per clump and diameter at breast height (DBH), recorded at 1.30 m above ground. Only culms older than three years were sampled, identified using a morphological technique developed by the author. Biomass was estimated using DBH and height through established allometric models. The results showed that soil composition had a significant effect on DBH and height, with T2 yielding the highest values. Mulching significantly improved DBH, although its effects on height and biomass were not statistically significant. Tukey’s HSD test confirmed significant differences among specific treatment combinations. Biomass accumulation was highest under T2 with mulch. These findings underscore the importance of organic matter inputs and proper soil management for improving bamboo growth. Mulching may further enhance performance, particularly in semi-arid environments such as eastern Ethiopia.