Key messages
- Native shrubs could be a potential forage resource as a browse to supplement livestock when pasture metabolizable energy values are low, especially in late summer and/or during winter when pasture growth is poor.
- Feed preference testing with sheep shows that most of the native shrubs assessed in the study are palatable.
About the study site
Massey University's Tuapaka Farm in the Manawatu provides a facility for quality research, teaching and extension in sheep and beef farming. It is particularly used in research investigating aspects of hill country farming. It is hill country vulnerable to soil erosion and brush weeds, especially gorse. Previously used for grazing sheep and cattle.
What is being trialled
- Griselinia littoralis (Pāpāuma), Coprosma repens (Taupata), Melicytus ramiflorus (Māhoe) and Salix schwerinii (willow) were planted in a steep 2 ha paddock in August 2020 to achieve a stocking rate of 3,200 plants/ha at 100% survival.
- Plots of individual species included about 330 plants, each replicated three times.
- Weed control was undertaken prior to planting with an aerial application of glyphosate in July 2020 and an aerial application of Haloxyfop in November 2021 to control grass weeds.
- Currently livestock have been excluded from the site, but sheep will be given access to the shrubs to assess sheep preferences under field conditions and post browsing recovery of shrubs. This work will potentially be undertaken in February 2025 when it is anticipated all species will be sufficiently well grown to withstand limited browsing, that is, not completely defoliated by browsing animals. The objective is to remove some foliage but leave sufficient canopy to allow shrubs to recover.
- Sheep feed preference testing and intake rates were measured under controlled conditions to assess the palatability of native shrubs, willow, and pasture.
Key findings
- Shrub survival at 2 years of age differed among species. Survival was highest in Salix (few losses), intermediate in Griselinia littoralis (Pāpāuma) and Coprosma repens (Taupata), with 75 and 69% survival respectively and lowest in Melicytus ramiflorus (Māhoe) with 24% survival.
- Among the native species height growth at two years was greatest in Griselinia littoralis (Pāpāuma - 106 cm) and Coprosma repens (Taupata - 100cm) and lowest in Melicytus ramiflorus (Māhoe - 87 cm).
- It is expected that shrubs will be sufficiently well grown to browse with sheep without high risk of post browsing mortality in February 2025
- Native shrubs were more palatable to sheep than willow and pasture.