Bamboo as bioresource in Ethiopia: management strategy to improve seedling performance (Oxytenanthera abyssinica)

Seedling emergence and subsequent survival and growth are vital for natural forest restoration or plantation establishment by means of seeds. Such information is lacking for the African bamboo species. Two experiments were carried out in a greenhouse to evaluate the influence of seed orientation and sowing depth of the lowland bamboo Oxytenanthera abyssinica on seedling emergence, survival and growth. A randomised complete block design was used. Seedling emergence in the seed orientation experiment followed the order embryo-end-up>lay-flat>embryo-end-down. Survival rate after 62 days decreased in the order lay-flat>embryo-end-down>embryo-end-up. Mean seedling height and number of leaves per seedling followed a similar pattern. Seeds sown on top of the soil surface and at 2.5 mm depth achieved faster and higher seedling emergence than those sown at 5 and 10 mm depths. However, mean seedling height and number of leaves per seedling were higher in 5 and 2.5 mm depths than surface and 10 mm depths. There were significant quadratic relationships between sowing depth and seedling height (p=0.034) as well as number of leaves per seedling (p=0.032), both peaking around 5 mm soil depth. Lay-flat orientation, which is the most frequent position in broadcast sowing, is recommended at 5 mm sowing depth for the lowland bamboo based on overall performance in seedling emergence, survival and growth.