Mapping groundcover of clover species in hill pastures in Wairarapa

Abstract

Tokaroa Farm (608 ha) with sheep and beef in the Wairarapa has predominantly sunny, north-facing slopes. Average annual rainfall is 810 mm with three months summer-dry. High quality pasture is needed in late winter/early spring for lactating stock and in spring to finish stock early. The survey mapped the distribution of resident subterranean (sub) and white clovers across four land classes based on slope and aspect. ArcGIS identified 60 GPS points that were visually assessed in December 2019 and November 2021. At the majority of points in both years, both white and sub clover were present. In 2019, white clover groundcover was 18.1% and higher (P<0.05) than sub clover at 12.6%. Management class had no effect. In 2021 there was no species effect (both ~11%) but there was a trend (P=0.062) for less white clover
groundcover in the ‘shady’ class (6.7%) than the ‘flat’ class at 17.5%. Pasture management was focused on promoting early season sub clover, but the unexpectedly high groundcover of white clover provided feed during wetter than average summers. Understanding the continuum from summer-dry annual sub clover areas to summer-wet perennial white clover dominance across New Zealand pastures provides tools for the selection and management of appropriate legumes.