Abstract

This study investigates the comparison of mechanical properties of wheat and rice straw such as shear strength, specific shearing energy and cutting forces. The experiments were conducted at three loading rate of 15, 20 and 25 mm min^-1 and three internode positions 70 (N1), 130 (N2) and 190 (N3) mm down from the ear. Results show that by increasing the loading rate, strength of wheat and rice straw changed from 8.12 to 22.94 and 6.06 to 14.33 MPa and specific shear energy was varied from 12.10 to 18.64 and 10.40 to 16.17 mJ mm^-2, respectively. Moreover, the values of cutting forces of wheat and rice straw were within the ranges 13.23 to 19.50 and 9.40 to 16.70 N. Whereas the shear strength, specific shearing energy and cutting force were higher at higher loading rate at the third internode of both straw internode positions. The shear strength, specific shearing energy and cutting force of rice straw were significantly higher (p<0.05) than that of wheat straw. With respect to the findings of the present research study, it is concluded that with decreasing loading rate of cutting blade toward the first internode, more energy can be saved by harvesting and threshing machines.

Key words: Cutting force, rice straw, shear strength, specific shearing energy, wheat straw.

Abbreviation

WS, Wheat straw; RS, rice straw.