Whatawhata Integrated Catchment Farm

This long-term project began in the 1990s to examine the impact of land use and management change on the system performance of a Waikato hill country catchment farm. The multi-stakeholder group established sustainable agriculture goals at the outset and monitored farm performance, water quality, greenhouse gas profile and indigenous biodiversity to verify expected improvements.

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Environmental impact summary

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NIWA - Summary of environmental impact (pdf 2 MB)

About

The Whatawhata Integrated Catchment Management project is led by AgResearch and NIWA and brought together researchers from the farm systems, environment and social sciences domains to investigate the impacts of pastoral farm practices on key environmental management outcomes: water quality, indigenous biodiversity and climate change mitigation. This work was undertaken in the context of low-altitude summer-dry pastoral hill country that occupies a large proportion of the landscape in the North Island of New Zealand.

The project went through three distinct phases of planning, forecasting and implementing land use change. The first critical step was the establishment of a multi-stakeholder oversight group. This comprised representatives from research, policy and practise: AgResearch (social and farm systems research), NIWA (environmental research), Manaaki Whenua Landcare Research (environmental research), Waikato Regional Council, Waikato District Council, Department of Conservation, Federated Farmers, individual farmers, foresters and local hapuu Ngaati Maahanga.

Once the multi-stakeholder group had worked collectively to establish goals and indicators, a case study block was selected. This area was approx. 300 hectares of hill country pastoral land in the upper headwaters of the Mangaotama Stream, which drains into the Waipa River below Whatawhata township. The block had been part of the Whatawhata Research Centre since the 1970s.

Timeline

Catchment farm system

Some key characteristics of the case study catchment farm, typical of much of the western Waikato hill country pasture lands, include:

Pre 2000:

296 hectares of steep, low altitude, hill country
Mild temperate climate prone to short-term summer drought
Waingaro steepland sedimentary soils and Mairoa ash soils on ridges
75% of land prone to erosion – classified as Land Use Capability Classes 6 and 7
Good fencing, stock water and access tracks as part of the research station
20 km of flowing streams
8 hectares of remnant native bush in 7 gully fragments
Romney sheep and Angus cattle breeding livestock enterprises
Lots of weed issues: gorse, blackberry, foxglove, inkweed

Key elements of the land use and management change decisions made by the multi-stakeholder group in 2001 include:

Post 2001:

153 ha of Pinus radiata forestry (52% area), high tree density, single-thinning silviculture on the most erodible and weed-prone areas.
128 ha of intensified pastoral (43% area), increased lambing production and facial eczema tolerance through improved sheep genetics, 18-month bull beef enterprise to minimise heavy cattle damage to hillslopes, tactical use of nitrogen fertiliser in autumn, space-planted poplar poles to stabilise soil in small gullies unsuitable for forestry, fenced almost all streams
15 ha of native forest restoration (5% area), mixed-species native shrub riparian plantings around existing bush fragments, small kauri & totara plantations

An area of native plantings on the Whatawhata integrated catchment farm

Monitoring: 1996-2020

Monitoring of waterways within the catchment farm had been in place since 1996 and much data on farm performance was available from research records. This provided a baseline against which the outcomes of the land use and management changes could be compared. Post-2001, monitoring focused on three areas: farm business performance, ecosystem health (particularly water and native forest) and environmental performance (particularly water quality and greenhouse gas balance).

Sustainable Business	Healthy Ecosystems	Environmental Performance
Soil fertility Pasture production Lambing and calving % Lamb and bull growth rates Farm costs (maintenance, fertiliser) Farm profit Return on capital	Stream flow Water clarity and temperature Fish and aquatic insects Bacteria in water - E.coli Bush fragment plant diversity Forest regeneration Native tree and shrub growth	Sediment and nutrients in water Greenhouse gas emissions Erosion

Results

A number of key indicators responded as expected to the management changes, such as livestock fecundity, meat production, enterprise profitability, stream temperature, aquatic invertebrates, forest regeneration. Other indicators did not. For example, there is no evidence after 20 years of any reduction in nutrient and sediment concentrations in water, although catchment flows have declined following tree planting across approximately 60% of the land area.

Farm performance:

The changes in the sheep and cattle enterprises, in combination with the shift to soils with greater inherent pasture productivity, substantially improved meat production and profitability.

	Pre-2001	Post 2001
Stocking rate (SU/ha)	8.8	10.0
Sheep:Cattle (SU wintered)	61:39	64:36
Lambs weaned (%)	109	126
Lamb production (kgLW/ha)	116	217
Beef production (kgLW/ha)	86	232
Wool production (kg/ha)	26	27
Sheep GM ($/SU)	30	45
Cattle GM ($/SU)	41	82

Aquatic habitat:

Reduction in stream temperature as a result of increasing riparian tree cover that shades streams. This improves habitat for sensitive aquatic invertebrates that a food for freshwater fish (eels and whitebait species

Forest health:

Regeneration of understory native plant species as a result of fencing livestock out of gully bush fragments. These plants will eventually fill forest gaps when canopy trees age and fall over in storms.