DOWNSLOPE MOVEMENT OF NUTRIENTS IN HILL PASTURE, TAITA, NEW-ZEALAND .1. WATER RUNOFF

Surface water was collected over one year in a study of downslope nutrient movement in hill pasture. Rain more than 5 mm usually produced downslope movement but in most events water entered the collectors from only a few metres upslope. Overland flow was seen in only 3 out of 44 rain events and these accounted for about 3 times more runoff than all the others combined during the year. It was estimated that downslope transfer per rain event from the areas above the collectors varied from 0.02-108 m3/ha (geometric mean 0.38 m3/ha) or 0.01-12% (mean 0.15%) of the rainfall.- from Authors