Maximising the subterranean clover content on a summer-dry Wairarapa hill-country farm through grazing management

Abstract

<jats:p>Tokaroa Farm is a 608-ha sheep and beef farm, in the Wairarapa. Paddock slopes range from flat to steep (&gt;25°) with a predominance of gentler north facing slopes and steeper south facing slopes. Annual rainfall is 810 mm and average summer dry is three months. Resident subterranean (sub) clover (Trifolium subterraneum L.) populations were identified on an uncultivatable north-west facing hill slope in 2015, and a management plan devised to increase its contribution to pastures. Exclosure plots showed that an eight-week spell in spring 2016 increased resident sub clover groundcover from 13 to 54%, while in the lightly grazed paddock control sub clover increased from 10 to 28%. There was a positive linear relationship (R2=0.51) between the total number of established sub clover seedlings on 30 March 2017 and the previous spring sub clover groundcover (%) on 25 November 2016. In October 2017, the effect of the spring 2016 exclosure treatments was still evident with 57% sub clover groundcover in the eight-week spelled areas compared with 37% in the control despite all the exclosures being grazed in 2017.Sub clover management strategies were developed, using slope and aspect, and applied to a GIS map of Tokaroa Farm. This suggested that 53% of the farm could have sub clover overdrilled into it and 29% could have the resident sub clover population actively managed and/or oversown with sub clover seed.</jats:p>

Sampling methods for clover species in grazed pastures to diagnose mineral deficiencies

“…Samples of sub and white clovers were collected from three dryland pasture sites from October 2017 to January 2019 (Table 2). At the time of sampling, the Tokaroa Farm site was a set-stocked clover-grass pasture (Olykan et al 2019), and the Ashley Dene and Iversen sites were rotationally grazed clover-grass pastures. Sample sorting was based on selecting fully expanded functional lamina, not visibly discoloured by disease, nutrient deficiency, senescence, or affected by pest damage, that also had a full petiole (leaf stem) as indicated by the presence of the stipule.…”

“…Sub clover is the dominant legume in areas where the summer-dry period is usually longer than three months and white clover (T. repens) is normally absent (Costello & Costello 2003;Grigg et al 2008). In pastures where summer water stress is less severe, sub clover and white clover may co-exist with sub clover dominating on sunny hill slopes and white clover thriving on shady slopes (Gillingham et al 1998;Olykan et al 2019).…”

Changes in New Zealand red meat production over the past 30 yr

“…In summer dry regions, there has been an emphasis on utilizing any flat or cultivatable areas (<15° slope) to provide lucerne ( Medicago sativa L.) direct fed to ewes and lambs to transform on farm performance ( Avery et al, 2008 ; Moot et al, 2019 ). For steeper summer dry regions, emphasis has been on managing subterranean clover ( T. subterraneum L.), as the earliest growing of the annual legumes, with equally dramatic on-farm results ( Grigg et al, 2008 ; Olykan et al, 2019 ).…”

Mapping groundcover of clover species in hill pastures in Wairarapa

“…Recent research at Tokaroa Farm in the Wairarapa focussed on the management of sub clover in the hill pastures grazed by sheep and cattle (Olykan et al 2019). Because of the predominance of flats and sunny northfacing slopes (78% of the property) and the summer-dry environment, Olykan et al (2019) hypothesised that the best legume for this farm was sub clover. However, the authors noted that both sub and white clovers co-existed on a west-facing hill slope and, anecdotally, there were 'wetter' summers when white clover grew well.…”