TREE PASTURE INTERACTIONS AT A RANGE OF TREE DENSITIES IN AN AGROFORESTRY EXPERIMENT .1. ROOTING PATTERNS

The effects of tree density on the distribution of tree and pasture roots under an agroforestry experiment were investigated. Trees were planted in a Nelder fan design, and three planting densities of 2150,304 and 82 stems per hectare were chosen for this study. Proximity to trees and increase in tree density reduced pasture root growth, with lowest concentrations of pasture roots occurring under the highest tree density. Tree root systems were deeper and denser at high tree densities, although total length and mass of roots produced per tree decreased with increasing tree density. Tree root: shoot ratios increased as tree density decreased owing to greater root production at low tree densities. © 1990 CSIRO. All rights reserved.