5% during the rainy season. Influence of hedgerows on rhizome mortality
was significantly greater in gliricidia than in leucaena plots throughout the
sampling period. Mortality in gliricidia also differed significantly from that in
control plots. Given the near complete canopy cover by the hedgerows
during the rainy season, we suggest that the speargrass rhizome mortality
observed in both gliricidia and leucaena plots was caused by shading of the
speargrass by these hedgerows. Increase in rhizome mortality appears to be
common occurrence in rhizomatous grasses as they go through environmental
stresses. Horowitz [1972] reported that over-wintering rhizomes of
johnsongrass in open vegetation decayed and were replaced gradually by new
rhizomes. Gliricidia and leucaena hedgerows caused 31% and 25% rhizome
mortality respectively in speargrass.