Fine Root Biomass of Erica trimera (Engl.) Along an Altitudinal Gradient on Bale Mountains, Ethiopia

Abebe, Worku (2007) Fine Root Biomass of Erica trimera (Engl.) Along an Altitudinal Gradient on Bale Mountains, Ethiopia. Masters thesis, Addis Ababa University.

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Abstract

The responses of fine roots to a changing environment are suggested to affect the growth and form of an individual plant or the structure and function of forest ecosystems. The depth-wise distribution and seasonal variation of fine roots of Erica trimera was investigated at three altitudinal levels, i.e., 3000, 3300 and 3500 masl up to 40 cm depth separated into three depth classes (0 - 10, 10 - 20 and 20 - 40 cm) using sequential soil coring. Soil chemical characteristics and moisture were analyzed for all the three altitudinal levels and depth classes. Total fine root mass and biomass increased significantly with altitude. Total nitrogen, available phosphorus, organic carbon, moisture content and pH of the soils increased significantly with altitude. In the two lower altitudinal levels, 3000 and 3300 masl, fine root mass and biomass decreased as depth increased, but at the higher altitude (3500 masl) fine roots tended to be more concentrated at the deeper depths. In all of the three sites the availability of soil nutrients and soil acidity showed a tendency to decrease as depth increased. The highest fine root mass and biomass was recorded at the major rainy season followed by the transition period, the small rainy season and dry period, in that order. The higher belowground biomass and lower aboveground biomass in contrast to higher soil nutrients at higher altitudes suggested that sink limitation may occur at the Erica trimera’s upper altitudinal limit due to the lower temperature. The night frost at higher elevation that is sever above 10 cm in the soil may also be responsible for the limited abundance of fine roots at the depth of 0 - 10 cm than at the two deeper depth classes (10 - 20 and 20 - 40 cm). The highest fine root mass during the major rainy season and lowest fine root mass in the dry season indicated that soil moisture was critical in governing the pattern of root growth in these ecosystems. Fine root production increased markedly from 35.75 kg ha-1 yr-1 at 3000 malsl and 65.37 kg ha-1 yr-1 at 3300 masl to 158.64 kg ha-1 yr-1 at 3500 masl. The figures indicate that fine root production and turnover by this species plays an important role in global carbon sequestration.

Item Type: Thesis (Masters)
Subjects: Q Science > QH Natural history > QH301 Biology
Q Science > QK Botany
Divisions: Africana
Depositing User: Selom Ghislain
Date Deposited: 22 Jun 2018 12:40
Last Modified: 22 Jun 2018 12:40
URI: http://thesisbank.jhia.ac.ke/id/eprint/4265

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