Characterization and Evaluation of the Mechanical and Physical properties of Tef stem (Eragrostistef (Zucc.)Trotter)

Abstract

Tef (Eragrostistef (Zucc.)Trotter) is atypical crop growing in most areas of Ethiopia, with the first area coverage. In this study mechanical properties of Tef stem the major four varieties, viz;  Local, Dz-Cr-438- (Kora), Dz-Cr-387/RIL-355(Quncho) and Dz-01-1880 (Guduru) was determined. The factors considered were moisture content, diameter and thickness of the Tef stem and analyze their mechanical properties using Texture Analyzer and Universal Testing Machine. The result indicated that the minimum and maximum value of modulus of elasticity was 0.13 and 2.6 Gpa at  moisture level 8.82% and 16.6%; 1.03 and 3.6Gpa at moisture level 10.32% and 13.79%; 0.85 and 3.22Gpa  at moisture level 7.65% and 12.72%; 1.27 and 3.88Gpa at moisture  level 5.5% and 19.70% at  upper and bottom position for Local, Kora, Quncho and Guduru varieties respectively.  The shear stress at different moisture content was 8.58 and 32.12Mpa ; 6.30 and 28.40Mpa ; 10 and 26.30Mpa ; 2 and 29.60Mpa  at  upper and bottom position for Local, Kora, Quncho and Guduru varieties respectively. The ability to track significant differences between the varieties and their individual mechanical and physical properties provides a path forward for tailoring harvesting, threshing and separation  operations. To tackle the problem of lodging it is better to look on the morphological structure of each varieties of Tef stem that has better modulus of elasticity, flexural rigidity and diameter of the stem. Since, the Tef stem has better mechanical properties than some cereals it is recommended to identify the fiber properties and use as material for composite.