Water and Soil Conservation Act 1967
After a review of New Zealand’s soil conservation in 1964, the Water and Soil Conservation Act was passed in 1967. A Water and Soil Division was set up within the Ministry of Works and Development. Under its control were the Soil Conservation and Rivers Control Council, the Water Pollution Control Council and the Water Allocation Council.
Importantly, at local level the control lay with each catchment authority, via the regional water boards.
Emphasis was placed on measuring the extent and types of erosion through land inventory surveys and land capability assessments.
The end of subsidies
The removal of agricultural subsidies in the late 1980s sparked the conversion of marginal farm land to plantation forestry, or back to native bush. These changes are now seen as beneficial in terms of reducing erosion. But the loss of subsidies halted many erosion control measures by catchment boards, as landowners were no longer keen, or could not afford to carry them out.
Resource Management Act 1991
The Resource Management Act 1991 is based on the sustainable management of resources (including soils) and encourages long-term planning.
Regional councils (essentially the former catchment boards) and territorial authorities (district and city councils) implement the act under the guidance of the Ministry for the Environment.
The councils’ main responsibilities are:
- to manage environmental, resource and transport planning, including the sustainable use of land, air and water
- to protect communities against the effects of flooding.
Erosion damages water quality
A major focus for the councils is water quality. This is affected by soil run-off, which carries sediment and nutrients (mostly nitrogen and phosphorus) into waterways. Phosphorus enters waterways in dissolved form, and attached to soil particles. Excessive nutrients in the water can cause excessive growth of aquatic plants, which lowers the oxygen content and affects fish life.
Concern over water quality has renewed the interest in soil conservation. Many regional councils have identified erosion as a major issue. A Manawatū plan has been developed to encourage hill country farmers to plant 77,000 hectares in trees. It is proposed that farmers be offered a government subsidy, and money from local rates. In this way, the subsidy system, scrapped in the 1980s, has re-emerged.