Root density was highest in the upper 15 cm soil layer and decreased with increasing depth (Fig. 6). The surface soil layer contained more than 1.0 cm of root -3 of soil up to a horizontal distance of 1.25 m, beyond which there was a sharp decline in root density. Similarly, the decline in root density with increasing depth from 7.5 cm to 22.5 cm was very marked. Almost 36% of total root density in the 2.0 x 2.0 m area investigated was in the upper most 15 cm of soil.