Glossary

Capability: Suitability for productive use, after taking into account the various physical limitations the land may have.

Catchment Protection (Land): Class 8 land which has such unfavourable characteristics that it is unsuited for agricultural, pastoral, or forestry use, although it is often well suited for recreational and wildlife use, and for water yield.

Climatic limitations: Limitations for the growth of pasture, crop and tree species, such as rainfall, temperature, wind and frost.

Community of interest: Problems shared by a group, largely as cause and effect, and which require collective effort to resolve.

Compound slopes: Used in inventory code when slope patterns cannot be separated at the scale of mapping, and are recorded as a complex using double or multiple symbols, e.g. D+E.

Conservation planning: Based on land inventory and land use capability assessment, a series of one or more five-year programmes are compiled which incorporate two concepts:

• The extent of the physical measures required to meet the magnitude of the conservation problems, and the degree of financial assistance applicable to combat existing or potential erosion.
• The ‘tailoring’ of these measures to the ability of individual farmers to meet the local share, from money budgeted for the purpose.

Conservation trees: Tree species used specifically for erosion control, e.g. willows and flame trees.

Conservation works: Consist of the following practices:

• conservation fencing (including cattle proofing),
• tree planting (open, close, windbreaks, pair planting),
• gully control structures such as debris dams,
• drop structures and flumes,
• terraces,
• water diversion (graded banks, spring tapping, pasture furrows),
• regulating dams,
• stock ponds,
• strategic firebreaks,
• revegetation including over-sowing and topdressing,
• sod seeding,
• bulldozing of tunnel gullies,
• retirement from productive use.

Degree of erosion: Extent of sheet, wind, and scree erosion is recorded on an areal basis as the percent of bare ground or area eroding. However soil slip, slump, debris avalanche, earth flow, rill, gully, tunnel gully, and streambank erosion are recorded in terms of seriousness, which is decided with reference to standard selected sites, parent material, physical loss of land, and cost of repair.

Degree of limitation: Applies to the Land Use Capability Classes, and expresses the relative limitations to sustained use, from Class 1 to Class 8.

Erosion control forestry:

• Planting exotic forest species principally for soil conservation and water management purposes but with a variable component of production permitted.
•  Management of indigenous forests principally for soil conservation and water management purposes but with some selective milling permitted (also see production forestry).

Field survey: As referred to in land inventory mapping, is the field observation, measurement and recording of the physical factors of the landscape in symbol form on a suitable base map.

Forestry potential: The potential for establishment of productive exotic forest, based on assessment of the physical factors of the site, but not on a full-scale study of economics, transport, markets, etc.

Hazard: The danger/risk of erosion and/or flooding.

Homogenous mapping units: At the scale of mapping the inventory factors (rock type, soil, slope erosion severity and type and vegetation cover) are considered homogeneous [of the same kind; alike] within the mapping unit.

Kind of limitation: The single most limiting factor to the use of land for common agricultural purposes. Four kinds of limitation are recognised:

• erosion (e),
• excess water (w),
• root zone limitations (s),
• climate (c).

Land Resource Inventory (LRI): An inventory of the five physical factors considered to be critical for long-term sustainable land use; rock type, soil, slope angle, erosion type and severity, vegetation.

Land Resource Inventory (LRI) map unit: The land contained by a mapping boundary within which each of the physical characteristics recorded in the inventory is uniform at the scale of mapping.

Land Use Capability unit: The land contained by a mapping boundary within which each of the physical characteristics recorded in the inventory is within the range of those defined for a specific LUC Unit. The LUC Units group together areas where similar land inventories have been mapped, which require the same kind of management, the same kind and intensity of conservation treatment, and are suitable for the same kind of crops, pasture or forestry species, with similar potential yields.

Map unit: The area enclosed by a boundary indicating that within the limitations imposed by the scale of mapping the information mapped is homogeneous within that area i.e. rock type, soil, land use capability etc.

Modal classes: When formulating Land Use Capability standards each soil grouping is usually assigned a capability class. Variables such as slope, elevation, or erosion, may then be of significance and warrant placing variants in a higher or lower capability class.

Multiple symbols: Are used to denote that at the scale of mapping, there are two or more inventory factors or land use capability classes present within the mapping unit. The first recorded component is dominant, e.g. rock types Af+Pt; soils 99+90d; slope C+D … land use capability classes 3e4+6e12 etc.

Multiple use concept: Flexible land use and management that meets society’s objectives and achieves sustainable yields whilst maintaining the resource.

Native pasture: Grasslands dominated by poa tussock, fescue tussock, snowgrass, and red tussock, and native grasses such as danthonia and fescue, and various small herbaceous plants which extended over considerable areas of New Zealand at the time of European settlement.

New Zealand Land Resource Inventory (NZLRI): A national land resource inventory survey that used the land use capability method of land evaluation at a nominal scale of 1:50,000 (1:63,360), which was initially completed in the late 1970s (1st Edition), with limited 2nd Edition regional remapping in Northland, part Waikato, Gisborne East Coast, and Marlborough in the 1990s.

New Zealand Land Resource Inventory (NZLRI) Worksheets: The map presentation of NZLRI inventory codes (rock type, soil, slope angle, erosion type and severity, vegetation cover) and land use capability codes.

Pastoral use: Growing of pasture to be harvested by grazing animals, but in some cases, e.g. lucerne, to be harvested by machine and fed to grazing animals. The term may also embrace the growing of fodder crops for on-farm supplementary feeding of animals.

Polygon: A series of points that are combined together topologically to create a two-dimensional enclosed space, equivalent to a map unit.

Production forestry: Forests managed principally for commercial wood production.

Protection forestry: Forests managed principally for soil conservation and regulation of water (also see erosion control forestry).

Protective blocks: Spaced or close planted blocks of trees, creating strong points to control gully head enlargement and the gradient of the longitudinal gully profile.

Recommended land use: A legacy component of early Land Use Capability surveys, whereby a map of recommended land use was prepared to accompany the Land Resource Inventory and the LUC classification. Simply recognises that some land uses are more suited (or less suited) to particular land types and classifications. Similar to potential land use used in NZLRI extended legends.

Reconnaissance surveys: Quick investigative surveys to gain preliminary information for planning more comprehensive surveys.

Soil and water conservation plans (farm plans): A conservation management plan designed to address soil erosion and water control issues through management, and the installation and maintenance of conservation works. Such a plan includes:

• An initial land inventory survey and land use capability assessment 
• The design of a conservation programme based on land use capability, and effective, economic soil and water conservation techniques. 
• An agreement between the regional authority and the farmer to carry out specified works or practices within a prescribed period. 

Soil depth: Soils are assigned to one of five depth/stoniness phases according to their depth above gravel, bedrock or stone in the upper 20 cm:

• Deep (>90 cm),
• Moderately deep (45–90 cm),
• Shallow (20–45 cm),
• Very shallow (<20 cm),
• Stony (5–35% stones in upper 20 cm),
• Very stony (>35% stones in upper 20 cm). 

Soil profile: A vertical section of a soil showing all its horizons to 100 cm depth.

Soil set: A convenient mapping unit used on general surveys, and is a grouping of soils with like profiles or like assemblages of profiles. Its constituent soils need not be geographically related.

Soil structure: The way in which soil particles are aggregated into soil peds. Structure is described by ped size (fine, medium, or coarse), shape, and how strongly they are formed (weakly, moderately or strongly). The presence of peds is important because spaces are left between and within them. These spaces are necessary for root growth and the movement of water and air within the soil.

Soil texture/texture class: Soil texture is used to describe the particle distribution of those particles in a mass of soil that are less than 2 mm in diameter. Particles coarser than 2 mm are described as gravel and are not regarded as a textural component. Soil texture is described as a class determined from a standard texture triangle based on the relative proportions of sand, silt and clay.

Tree crops: The growing of trees for fruit and/or nut production.