Establishment, production and regeneration of subterranean clovers in the Mackenzie Basin, New Zealand

Abstract

The ‘Red Flats’ on Omarama Station in the Mackenzie Basin, has a winter cold, summer dry environment and soils with low plant available water (<60 mm in the top 1 m), and low pH(H2O) (5.2) and high aluminium (8 mg/kg) below 75 mm. The site received 3 t of lime, 300 kg sulphur-super, boron (B), molybdenum (Mo) and herbicides to eliminate hieracium (Hieracium pilosella). Twelve cultivars of subterranean clover (Trifolium subterraneaum), ‘Bolta’ balansa clover (T. michelianum), and perennial ‘Rossi’ red clover (T. pratense), were direct-drilled in February 2016. Over the next 3 years their frost tolerance, productivity and persistence were compared with the resident haresfoot clover (T. arvense). Balansa and the subterranean clovers all survived the 2016 and 2017 winters. The subterranean clovers maximum yield was 4.3 t DM/ ha after successful germination in February 2016 when sufficient rain extended the spring growing season into November. Subterranean clover cultivars from subspecies subterraneum yielded well in 2016, averaging 3.3 t DM/ha, as did the brachycalycinum ‘Antas’ with 3 t DM/ha. During the short season of 2017, the subterraneum ssp. cultivars ‘Denmark’ and ‘Karridale’ established the highest ground covers and ‘Antas’ the lowest. In 2018, ‘Antas’ had the lowest emergence rate and autumn yield. ‘Karridale’ had the highest re-establishment rate and the yanninicum ‘Trikkala’ the highest autumn yield (1.3 t DM/ha). Cultivars with low hardseededness ratings were the most successful at re-establishment in autumn 2017. Balansa clover was also persistent. In the favourable 2016 growing season the late-flowering resident haresfoot clover grew into early summer and yielded 3.7 t DM/ha. Red clover yielded 1 t DM/ha in 2016, but did not persist. Results suggest that medium-late flowering softer seeded subterranean clover cultivars and ‘Bolta’ balansa clover, are suitable for this environment.