Takaroa


What was achieved

  • Development of appropriate sampling procedures for clover species for diagnosis of nutrient status for fertiliser recommendations.
  • Increased understanding of how subterranean (sub) clover content can be maximised on a summer-dry Wairarapa hill-country farm through grazing management.
  • Increased understanding of the continuum from the summer-dry sub clover environment to summer-wet perennial white clover pastures.

About the study site

Tokaroa Farm, in Wairarapa, is a 608 ha sheep and beef farm owned the Nicholson family. Paddock slopes range from flat to steep (>25°), with a predominance of gentler north-facing slopes and steeper south-facing slopes. Annual rainfall is 810 mm and the average summer dry is three months.

 

Study 1 - Sampling methods for clover species in grazed pastures

What was trialled

  • The differences in nutrient concentrations between laminae (leaflets) and petioles (leaf stems) of sub clover and white clover were measured. 
  • Sub and white clovers were handpicked then separated into lamina and full petiole and chemically analysed for nitrogen (N), phosphorus (P), potassium (K) and sulphur (S).
  • A subset of samples was also analysed for metabolisable energy (ME), crude protein, acid detergent fibre (ADF) and neutral detergent fibre (NDF) to understand animal nutrition value of the two clovers.

Key findings

  • The lamina concentrations of N, P and S were higher than in the petiole across both species. Therefore, the diagnosis of clover nutrient status for fertiliser recommendations should be based on lamina-only samples.
  • Mixed pasture samples for nutritive value analysis should include clover laminae and petioles to simulate intake by grazing livestock.
  • Lamina + petiole K concentrations were lower in sub clover than white clover.
  • ME did not differ between lamina and petiole but crude protein was three times higher in the lamina than the petiole.

Keen to know more?

Olykan et al. 2019: Sampling methods for clover species in grazed pastures to diagnose mineral deficiencies

 

Study 2 - Maximising the subterranean clover content

What was trialled

  • Resident sub clover populations were identified on an uncultivatable north-west facing hill slope and a management plan devised to increase its contribution to pastures.
  • The effect of the management plan on resident sub clover was measured over two seasons.

Key findings

  • The grazing management plan, which was based on observing the sub clover lifecycle, rotational grazing and light set-stocking cattle, increased the resident sub clover content of the hill country pastures.
  • The percentage of sub clover groundcover increased in this summer-dry hill-country environment when the grazing regime was changed to focus on promoting its reseeding and re-establishment.
  • The biggest challenge for maintaining a sub clover pasture was grass control throughout the year.

Keen to know more?

Olykan et al. 2019: Maximising the subterranean clover content on a summer-dry Wairarapa hill-country farm through grazing management

 

Study 3 - Mapping groundcover of clover species

What was trialled

  • The distribution of resident sub and white clovers across four land classes were mapped based on slope and aspect.
  • The proportion of sub and white clover groundcover within these land classes was visually assessed over two seasons.

Key findings

  • The clover management classes used in this study can be used as a practical guide to the long-term management of clover on this, and similar properties.
  •  It was thought that sub clover was the best suited legume for this property, however, both sub and white clovers were observed co-existing on a west-facing hill slope. Therefore, the use of both clovers in environments that experience variable and inconsistent spring and summer rainfall should be encouraged.
  • Though the farms pasture management was focused on promoting early season sub clover, the unexpectedly high groundcover of white clover provided feed during wetter than average summers.

Keen to know more?

Olykan et al. 2022: Mapping groundcover of clover species in hill pastures in Wairarapa

 

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