Lysimeter and interception studies in narrow-leaved snow tussock grassland

Abstract

Non-weighing lysimeters were constructed to measure the net water balance of untreated, burnt, and clipped narrow-leaved snow tussocks (Chionochloa rigida) and of a blue tussock (Poa colensoi) sward at 915 m on the Rock and Pillar Range, Central Otago. Lysimeters with untreated tussocks produced more water (66% of a yearly rainfall) than burnt tussocks (57%), producing in turn slightly more water than clipped tussocks (48%) or the blue tussock sward (45%). Interception was recorded from clipped and untreated snow tussocks mounted over rain gauges. Untreated tussocks on Mt Cargill intercepted four to six times the precipitation recorded in standard gauges. The problems and limitations involved in measuring water balance using these lysimeters in this environment are discussed.