This project aimed to understand how to better manage tagasaste (commonly known as tree lucerne) on-farm in the Hawkes’ Bay region and Taupō.
Field trials were carried out at three sites to assess the following:
- Seed germination and establishment of tagasaste.
- Forage production and nutritive value of tagasaste.
- Weed risk assessment for tagastaste.
- Production of grass and legume pasture species grown in pasture-tagasaste systems.
There is huge potential growth for the sheep and beef sector on hill country in New Zealand. Around 6 million ha of hill country is too steep to cultivate but represents 54% of the land area on which sheep and beef farming is undertaken in New Zealand, adding over $4 billion per annuum of export revenue to our economy.
East Coast farmers are concerned about the fragility of their soil and the challenges of adverse events. Their topsoil is critical to their business and its erosion and loss represents a huge reduction in the resilience of the landscape and productive potential. The depleted soil is more prone to drought, more easily invaded by woody weeds, and represents a significant loss of stored carbon from the landscape.
Soils need more than just pasture to hold them in place, but forestry is not always the best option. A potential solution is the use of shrubby vegetation e.g. Tagasaste, as a soil stabiliser as well as a stock feed. Tagasaste is a hardy nitrogen fixer with high protein foliage suitable for sheep and cattle that thrives on steep, erosion-prone, north-facing hill country. Tagasaste is suitable for both the dry shady slopes and sunny slopes, and the six-week lag time between production from the two aspects means there is the potential for two springs’ worth of stock feed. Additionally, Tagasaste provides shade and shelter to support animal welfare.
For more information on this project visit: https://www.sustainablehillcountrynz.com/
Nutrition from tagasaste
- Trees in Hawke’s Bay produced ~2.7 edible dry matter per tree per year with lowest production in autumn.
- The amount of metabolisable energy was 9.4 – 10.7 Mj/kg DM – equivalent to that of perennial ryegrass during summer and autumn.
- Crude protein varied from 17% to 23% when measured over three years.
- Neutral digestible fibre ranged from 32% to 43% when measured over three years.
- Mean concentration of macro and micro-elements in tagasaste (except phosphorous) exceeded those recommended for an adequate intake for sheep and cattle.
- Similar germination rates were observed when seeds were placed in boiling water vs when they were nicked and put in hot tap water.
- Establishing tagasaste in resident pastures in summer-wet hill country is unlikely to be successful from sowing seed.
- Removing 20% off the top of the tagasaste was sufficient to increased edible dry matter.
- Cocksfoot was the most successful understory pasture compared with other grasses.
- Lotus was the most successful understory legume compared with other legumes trialed.
Benefits of tagasaste
- Direct benefits of establishing tagasaste on hill country are estimated at $149.60/ha/yr.
- Other benefits of tagasaste include shelter, shade, soil conservation, soil improvement and biodiversity.
Benefit for farmers
This project shared practical experience on how to establish and manage tagasaste on hill country and has produced a handbook for guidelines on how to do this.
Timeline and investment
This was a three-year project completed in October 2021. B+LNZ’s investment is $165,000 over the duration of the project.
Year 1 and 2 (2018/19 and 2019/20) involved the establishment and management of tagasaste, sowing companion plants within the tagasaste-pasture systems and monitoring of tagasaste-pasture systems.
Year 3 (2020/21) focused on case studies to inform other farmers what was found.
- Three field days throughout the project
Popular press articles
- Wairoa Star – “Exciting results revealed in sustainable hill country trial”.
- RNZ National interview – “Talking about tree lucerne”.
- Frontiers in Sustainable Food Systems: “Vegetation options for increasing resilience in pastoral hill country”.
This is a Ministry for Primary Industries Sustainable Farming Fund project led by the Hawke’s Bay Regional Council (Peter Manson) with co-funding from MPI, B+LNZ and Ballance Agri-nutrients and in-kind support from Federated Farmers, Greater Wellington Regional Council and Waikato Regional Council.
Lead Scientists: Katherine Tozer (AgResearch), Grant Douglas (GBD Science), Ian Tarbotton (Ballance Agri-nutrients)
Farmers involved: Greg Hart, Nick Broad, Doug Avery, Dave Read, Luke Read.