14. Land and Soils

Dog on a hillside.

Summary

RPS Objectives

· The maintenance, and where possible, enhancement of the life-supporting capacity of soils, especially those which have potential to support intensive primary production.

· The protection of the soil resources, including soil quality and soil quantity, from degradation or loss as a result of unsustainable land uses and land use practices.

· The safeguarding of the life-supporting capacity of water and ecosystems from the adverse effects of unsustainable land uses and land use practices.

· The avoidance, remedying or mitigation of the adverse effects of plant and animal pests on the use of land, including its potential for primary production and natural ecosystems.

Pressures

· Approximately half of the region's land is used for intensive pastoral farming, with about 367,000 dairy cattle, 496,000 beef cattle and 534,000 sheep in Northland in 2006. A change to more intensive farming can lead to decreased water quality in waterways and reduced soil health.

· About 375,000 tonnes of fertiliser in total (including 212,000 tonnes of lime) was applied in Northland in the year ending 30 June 2002.

· Over half (720,000 ha) of Northland's land area is erosion prone land (i.e. has a Land Use Capability (LUC) erosion class of either 6e or 7e).

· There is an increased risk of unwanted organisms entering the region, partly as a result of climate change, which will continue to impact on agriculture, horticulture and natural ecosystems.

· Based on subdivision data supplied by the region's three district councils, (different year periods for each district) about 9% of Northland's prime soils for horticultural and agricultural (includes land resource inventory soil classes 1c1, 2e1, 2w1, 2s1, 3e1, 3s1 and 3s2) have been subdivided into 2,209 lots over approximately the last six years, particularly around Whangarei and Kerikeri (refer to section 14.2 for more information).

State

· Soil chemical properties at the 25 sites sampled in 2007 were generally good, however the physical properties at about half of the 25 sites indicated soil compaction was occurring. At these 25 sites, all heavy metals tested were within recommended guidelines.

· Approximately 30% of Northland's erosion prone land (land with LUC erosion class of 6e or 7e) had pastoral land cover in 2002. The majority of this land is being used and managed in a way that does not cause widespread or large scale erosion. There is also anecdotal evidence that some areas of erosion prone land in Northland have reverted from pasture to scrub or gorse over the last decade, as some farmers have moved away from using ‘marginal' land for pastoral farming.

· The occurrence and extent of most pest plants in the Regional Pest Management Strategy (RPMS) for Northland have been greatly reduced, with many ahead or on target for meeting the objectives in the RPMS.

Doing well

· Progress towards meeting the targets in the Northland Regional Action Plan for the Dairying and Clean Streams Accord is well underway.

· 21 Community Pest Control Areas have been established, or proposed for Northland, with 650 people engaged in biosecurity action on their own land, working cooperatively together, with over 22,000 hectares of private land under some form of pest management.

· The emphasis of biosecurity action is changing from managing established pests to meeting new pressures and recognising the potential damaging effects of new insect species, marine species and wind-borne diseases.

· Approximately 200 people from 50 different Northland companies attended erosion and sediment control workshops held by the Regional Council in 2006 and 2007.

Areas for improvement

· There were significant amounts of soil conservation research and work carried out in Northland in the 1970s and 1980s, such as dune protection through forestry planting. However, this soil conservation work has reduced in the last two decades. This coupled, with intensification of farming, has lead to an increased risk of erosion occurring on erosion prone land used for pastoral farming. There is some anecdotal evidence of poorly managed erosion prone pastoral land, but there is a lack of quantitative information on the extent of the problem.

· Much of the data used for this Land and Soils chapter was collected for national databases at five yearly intervals. For example, the most recent data available for the Land Cover Database was captured over the 2001/2002 summer and the last full census for the Agriculture Production Statistics was in 2002. Also the scope of the data, that is the range of parameters surveyed or tested, while adequate for national databases, is insufficient to enable catchment or even district-wide trends to be assessed and fully understood. Therefore more data and information is needed on land use in Northland to improve the accuracy and frequency of assessment at a catchment, district and regional scale. This would include increased routine monitoring of land use, health and density of vegetation cover, and soil quality on a greater number of soil types within the region to assess whether Northland's land and soils are being sustainably managed.

· Increased promotion and implementation of soil conservation are needed, particularly on erosion prone land.

· More joint agency plans and response to mitigate the effects of introduced plants, insects and animals, with support from crown agencies such as Biosecurity New Zealand, are needed.

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Published: 15 Aug 2008