Seasonal changes and the effect of temperature and leaf moisture content on intrinsic shear strength of leaves of pasture grasses

Abstract

The intrinsic shear strength of leaves of 6 temperate pasture grasses was measured using a guillotine. The intrinsic shear strength of the leaves was represented as the force required to shear a leaf corrected for the length of cutting blade in contact with the material. When green leaves were maintained at 100% relative humidity, their moisture content was maintained and their intrinsic shear strength remained constant over a 24-h period. Shear strength increased when leaves were allowed to dehydrate. Shear strength varied significantly over a growing season, with strength generally higher in summer and lower in winter. When grown in a constant regime with day/night temperatures ranging from 14/6