Trifolium ambiguum(Caucasian clover) in montane tussock grasslands, south island, New Zealand

Abstract

A field experiment was conducted at nine montane tussock grassland sites forming toposequences of soil temperature, moisture, and fertility in the southern Mackenzie Basin, South Island, to characterise the adaptational range and development dynamics of the above‐ and below‐ground growth of Trifolium ambiguum cv. Endura under different defoliation treatments over a two‐year period. Successful establishment, high productivity, and survival occurred on lower slopes and mid‐altitude north‐facing slopes, but this cultivar appears unsuited to mid‐altitude, shady aspects with dense Agrostis capillaris cover, and at higher elevation, tall‐tussock sites. Plant growth in the establishment year was mostly confined to primary crown and taproot/fibrous root growth, although early rhizome development occurred in plants on the lower sunny slopes. In the second year, growth was characterised by crown and rhizome shoots during spring and summer and by the expansion of the below‐ground rhizome/root components in summer and autumn. In Year 3, of the below‐ground components, only secondary rhizomes and secondary taproots were active centres of growth. Plant survival and all below‐ground components declined where defoliation occurred in spring and throughout the growing season in Year 2. Defoliation treatments did not affect the below‐ground components in Year 3. The potential of T. ambiguum as a pasture legume in these environments is discussed.